Update requirements

Generated with poetry export: $ poetry export --without-hashes -f requirements.txt > requirements.txt $ poetry export --without-hashes --dev -f requirements.txt > requirements-dev.txt I am trying `--without-hashes` to work around an error on pip install when running in CI: ERROR: In --require-hashes mode, all requirements must have their versions pinned with ==.
Run poetry update
2025-05-09 22:56:01 +02:00 · 2021-07-06 15:47:44 +03:00 · 2021-07-06 15:37:57 +03:00 · 2021-07-06 15:30:41 +03:00 · 2021-07-06 15:24:39 +03:00 · 2021-06-14 12:52:47 +03:00
25 changed files with 2747 additions and 809 deletions
--- a/.build.yml
+++ b/.build.yml
@ -1,19 +0,0 @@
-image: archlinux
-packages:
-  - python-pipenv
-sources:
-  - https://git.sr.ht/~alanorth/csv-metadata-quality
-tasks:
-  - setup: |
-      cd csv-metadata-quality
-      pipenv install --dev
-  - pytest: |
-      cd csv-metadata-quality
-      pipenv run pytest
-  - testcli: |
-      cd csv-metadata-quality
-      pipenv run pip install .
-      pipenv run csv-metadata-quality -i data/test.csv -o /tmp/test.csv -u --agrovoc-fields dc.subject,cg.coverage.country
-environment:
-  PIPENV_NOSPIN: 'True'
-  PIPENV_HIDE_EMOJIS: 'True'
--- a/.drone.yml
+++ b/.drone.yml
@ -0,0 +1,52 @@
+---
+kind: pipeline
+type: docker
+name: python39
+
+steps:
+- name: test
+  image: python:3.9-slim
+  commands:
+  - id
+  - python -V
+  - apt update && apt install -y gcc g++ libicu-dev pkg-config
+  - pip install -r requirements-dev.txt
+  - pytest
+  - python setup.py install
+  - csv-metadata-quality -i data/test.csv -o /tmp/test.csv -e -u --agrovoc-fields dcterms.subject,cg.coverage.country
+
+---
+kind: pipeline
+type: docker
+name: python38
+
+steps:
+- name: test
+  image: python:3.8-slim
+  commands:
+  - id
+  - python -V
+  - apt update && apt install -y gcc g++ libicu-dev pkg-config
+  - pip install -r requirements-dev.txt
+  - pytest
+  - python setup.py install
+  - csv-metadata-quality -i data/test.csv -o /tmp/test.csv -e -u --agrovoc-fields dcterms.subject,cg.coverage.country
+
+---
+kind: pipeline
+type: docker
+name: python37
+
+steps:
+- name: test
+  image: python:3.7-slim
+  commands:
+  - id
+  - python -V
+  - apt update && apt install -y gcc g++ libicu-dev pkg-config
+  - pip install -r requirements-dev.txt
+  - pytest
+  - python setup.py install
+  - csv-metadata-quality -i data/test.csv -o /tmp/test.csv -e -u --agrovoc-fields dcterms.subject,cg.coverage.country
+
+# vim: ts=2 sw=2 et
--- a/.github/workflows/python-app.yml
+++ b/.github/workflows/python-app.yml
@ -0,0 +1,41 @@
+# This workflow will install Python dependencies, run tests and lint with a single version of Python
+# For more information see: https://help.github.com/actions/language-and-framework-guides/using-python-with-github-actions
+
+name: Build and Test
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python 3.9
+      uses: actions/setup-python@v2
+      with:
+        python-version: 3.9
+    - name: Install dependencies
+      run: |
+        python -m pip install --upgrade pip
+        pip install flake8 pytest
+        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+        if [ -f requirements-dev.txt ]; then pip install -r requirements-dev.txt; fi
+    - name: Lint with flake8
+      run: |
+        # stop the build if there are Python syntax errors or undefined names
+        flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
+        # exit-zero treats all errors as warnings. The GitHub editor is 127 chars wide
+        flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
+    - name: Test with pytest
+      run: |
+        pytest
+    - name: Test CLI
+      run: |
+        python setup.py install
+        csv-metadata-quality -i data/test.csv -o /tmp/test.csv -e -u --agrovoc-fields dcterms.subject,cg.coverage.country
--- a/.travis.yml
+++ b/.travis.yml
@ -1,11 +0,0 @@
-dist: xenial
-language: python
-python:
-  - "3.6"
-  - "3.7"
-install:
-  - "pip install pipenv --upgrade-strategy=only-if-needed"
-  - "pipenv install --dev"
-script: pytest
-
-# vim: ts=2 sw=2 et
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -4,6 +4,121 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

+## Unreleased
+### Added
+- Ability to check for, and fix, "mojibake" characters using [ftfy](https://github.com/LuminosoInsight/python-ftfy)
+
+### Updated
+- Python dependencies
+
+## [0.4.7] - 2021-03-17
+### Changed
+- Fixing invalid multi-value separators like `|` and `|||` is no longer class-
+ified as "unsafe" as I have yet to see a case where this was intentional
+- Not user visible, but now checks only print a warning to the screen instead
+of returning a value and re-writing the DataFrame, which should be faster and
+use less memory
+
+### Added
+- Configurable directory for AGROVOC requests cache (to allow running the web
+version from Google App Engine where we can only write to /tmp)
+- Ability to check for duplicate items in the data set (uses a combination of
+the title, type, and date issued to determine uniqueness)
+
+### Removed
+- Checks for invalid and unnecessary multi-value separators because now I fix
+them whenever I see them, so there is no need to have checks for them
+
+### Updated
+- Run `poetry update` to update project dependencies
+
+## [0.4.6] - 2021-03-11
+### Added
+- Validation of dcterms.license field against SPDX license identifiers 
+
+### Changed
+- Use DCTERMS fields where possible in `data/test.csv`
+
+### Updated
+- Run `poetry update` to update project dependencies
+
+### Fixed
+- Output for all fixes should be green, because it is good
+
+## [0.4.5] - 2021-03-04
+### Added
+- Check dates in dcterms.issued field as well, not just fields that have the
+word "date" in them
+
+### Updated
+- Run `poetry update` to update project dependencies
+
+## [0.4.4] - 2021-02-21
+### Added
+- Accept dates formatted in ISO 8601 extended with combined date and time, for
+example: 2020-08-31T11:04:56Z
+- Colorized output: red for errors, yellow for warnings and information, green
+for changes
+
+### Updated
+- Run `poetry update` to update project dependencies
+
+## [0.4.3] - 2021-01-26
+### Changed
+- Reformat with black
+- Requires Python 3.7+ for pandas 1.2.0
+
+### Updated
+- Run `poetry update`
+- Expand check/fix for multi-value separators to include metadata with invalid
+separators at the end, for example "Kenya||Tanzania||"
+
+## [0.4.2] - 2020-07-06
+### Changed
+- Add field name to the output for more fixes and checks to help identify where
+the error is
+- Minor optimizations to AGROVOC subject lookup
+- Use Poetry instead of Pipenv
+
+### Updated
+- Update python dependencies to latest versions
+
+## [0.4.1] - 2020-01-15
+### Changed
+- Reduce minimum Python version to 3.6 by working around the `is_normalized()`
+that only works in Python >= 3.8
+
+## [0.4.0] - 2020-01-15
+### Added
+- Unicode normalization (enable with `--unsafe-fixes`, see README.md)
+
+### Updated
+- Update python dependencies to latest versions, including numpy 1.18.1, pandas
+1.0.0rc0, flake8 3.7.9, pytest 5.3.2, and black 19.10b0
+- Regenerate requirements.txt and requirements-dev.txt
+
+### Changed
+- Use Python 3.8.0 for pipenv
+- Use Ubuntu 18.04 "Bionic" for TravisCI builds
+- Test Python 3.8 in TravisCI builds
+
+## [0.3.1] - 2019-10-01
+## Changed
+- Replace non-breaking spaces (U+00A0) with space instead of removing them
+- Harmonize language of script output when fixing various issues
+
+## [0.3.0] - 2019-09-26
+### Updated
+- Update python dependencies to latest versions, including numpy 1.17.2, pandas
+0.25.1, pytest 5.1.3, and requests-cache 0.5.2
+
+### Added
+- csvkit to dev requirements (csvcut etc are useful during development)
+- Experimental language validation using the Python `langid` library (enable with `-e`, see README.md)
+
+### Changed
+- Re-formatted code with black and isort
+
 ## [0.2.2] - 2019-08-27
 ### Changed
 - Output of date checks to include column names (helps debugging in case there are multiple date fields)
--- a/25
+++ b/25
@ -1,25 +0,0 @@
-[[source]]
-name = "pypi"
-url = "https://pypi.org/simple"
-verify_ssl = true
-
-[dev-packages]
-pytest = "*"
-ipython = "*"
-flake8 = "*"
-pytest-clarity = "*"
-
-[packages]
-pandas = "*"
-python-stdnum = "*"
-xlrd = "*"
-requests = "*"
-requests-cache = "*"
-pycountry = "*"
-csv-metadata-quality = {editable = true,path = "."}
-
-[requires]
-python_version = "3.7"
-
-[pipenv]
-allow_prereleases = true
--- a/Pipfile.lock
+++ b/Pipfile.lock
@ -1,376 +0,0 @@
-{
-    "_meta": {
-        "hash": {
-            "sha256": "f8f0a9f208ec41f4d8183ecfc68356b40674b083b2f126c37468b3c9533ba5df"
-        },
-        "pipfile-spec": 6,
-        "requires": {
-            "python_version": "3.7"
-        },
-        "sources": [
-            {
-                "name": "pypi",
-                "url": "https://pypi.org/simple",
-                "verify_ssl": true
-            }
-        ]
-    },
-    "default": {
-        "certifi": {
-            "hashes": [
-                "sha256:046832c04d4e752f37383b628bc601a7ea7211496b4638f6514d0e5b9acc4939",
-                "sha256:945e3ba63a0b9f577b1395204e13c3a231f9bc0223888be653286534e5873695"
-            ],
-            "version": "==2019.6.16"
-        },
-        "chardet": {
-            "hashes": [
-                "sha256:84ab92ed1c4d4f16916e05906b6b75a6c0fb5db821cc65e70cbd64a3e2a5eaae",
-                "sha256:fc323ffcaeaed0e0a02bf4d117757b98aed530d9ed4531e3e15460124c106691"
-            ],
-            "version": "==3.0.4"
-        },
-        "csv-metadata-quality": {
-            "editable": true,
-            "path": "."
-        },
-        "idna": {
-            "hashes": [
-                "sha256:c357b3f628cf53ae2c4c05627ecc484553142ca23264e593d327bcde5e9c3407",
-                "sha256:ea8b7f6188e6fa117537c3df7da9fc686d485087abf6ac197f9c46432f7e4a3c"
-            ],
-            "version": "==2.8"
-        },
-        "numpy": {
-            "hashes": [
-                "sha256:03e311b0a4c9f5755da7d52161280c6a78406c7be5c5cc7facfbcebb641efb7e",
-                "sha256:0cdd229a53d2720d21175012ab0599665f8c9588b3b8ffa6095dd7b90f0691dd",
-                "sha256:312bb18e95218bedc3563f26fcc9c1c6bfaaf9d453d15942c0839acdd7e4c473",
-                "sha256:464b1c48baf49e8505b1bb754c47a013d2c305c5b14269b5c85ea0625b6a988a",
-                "sha256:5adfde7bd3ee4864536e230bcab1c673f866736698724d5d28c11a4d63672658",
-                "sha256:7724e9e31ee72389d522b88c0d4201f24edc34277999701ccd4a5392e7d8af61",
-                "sha256:8d36f7c53ae741e23f54793ffefb2912340b800476eb0a831c6eb602e204c5c4",
-                "sha256:910d2272403c2ea8a52d9159827dc9f7c27fb4b263749dca884e2e4a8af3b302",
-                "sha256:951fefe2fb73f84c620bec4e001e80a80ddaa1b84dce244ded7f1e0cbe0ed34a",
-                "sha256:9588c6b4157f493edeb9378788dcd02cb9e6a6aeaa518b511a1c79d06cbd8094",
-                "sha256:9ce8300950f2f1d29d0e49c28ebfff0d2f1e2a7444830fbb0b913c7c08f31511",
-                "sha256:be39cca66cc6806652da97103605c7b65ee4442c638f04ff064a7efd9a81d50a",
-                "sha256:c3ab2d835b95ccb59d11dfcd56eb0480daea57cdf95d686d22eff35584bc4554",
-                "sha256:eb0fc4a492cb896346c9e2c7a22eae3e766d407df3eb20f4ce027f23f76e4c54",
-                "sha256:ec0c56eae6cee6299f41e780a0280318a93db519bbb2906103c43f3e2be1206c",
-                "sha256:f4e4612de60a4f1c4d06c8c2857cdcb2b8b5289189a12053f37d3f41f06c60d0"
-            ],
-            "version": "==1.17.0"
-        },
-        "pandas": {
-            "hashes": [
-                "sha256:074a032f99bb55d178b93bd98999c971542f19317829af08c99504febd9e9b8b",
-                "sha256:20f1728182b49575c2f6f681b3e2af5fac9e84abdf29488e76d569a7969b362e",
-                "sha256:2745ba6e16c34d13d765c3657bb64fa20a0e2daf503e6216a36ed61770066179",
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-                "sha256:58f9ef68975b9f00ba96755d5702afdf039dea9acef6a0cfd8ddcde32918a79c",
-                "sha256:9023972a92073a495eba1380824b197ad1737550fe1c4ef8322e65fe58662888",
-                "sha256:914341ad2d5b1ea522798efa4016430b66107d05781dbfe7cf05eba8f37df995",
-                "sha256:9d151bfb0e751e2c987f931c57792871c8d7ff292bcdfcaa7233012c367940ee",
-                "sha256:b932b127da810fef57d427260dde1ad54542c136c44b227a1e367551bb1a684b",
-                "sha256:cfb862aa37f4dd5be0730731fdb8185ac935aba8b51bf3bd035658111c9ee1c9",
-                "sha256:de7ecb4b120e98b91e8a2a21f186571266a8d1faa31d92421e979c7ca67d8e5c",
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-            ],
-            "index": "pypi",
-            "version": "==0.25.0"
-        },
-        "pycountry": {
-            "hashes": [
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-            ],
-            "index": "pypi",
-            "version": "==19.7.15"
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-        "python-dateutil": {
-            "hashes": [
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-                "sha256:c89805f6f4d64db21ed966fda138f8a5ed7a4fdbc1a8ee329ce1b74e3c74da9e"
-            ],
-            "version": "==2.8.0"
-        },
-        "python-stdnum": {
-            "hashes": [
-                "sha256:d5f0af1bee9ddd9a20b398b46ce062dbd4d41fcc9646940f2667256a44df3854",
-                "sha256:f445ec32bf5246c90389204cabba465f494545371c29a83fa2d30e6c872a6763"
-            ],
-            "index": "pypi",
-            "version": "==1.11"
-        },
-        "pytz": {
-            "hashes": [
-                "sha256:26c0b32e437e54a18161324a2fca3c4b9846b74a8dccddd843113109e1116b32",
-                "sha256:c894d57500a4cd2d5c71114aaab77dbab5eabd9022308ce5ac9bb93a60a6f0c7"
-            ],
-            "version": "==2019.2"
-        },
-        "requests": {
-            "hashes": [
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-            "index": "pypi",
-            "version": "==2.22.0"
-        },
-        "requests-cache": {
-            "hashes": [
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-            "index": "pypi",
-            "version": "==0.5.0"
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-        "six": {
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-            "version": "==4.4.0"
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-        "entrypoints": {
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-            "version": "==0.3"
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-        "flake8": {
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-            "index": "pypi",
-            "version": "==3.7.8"
-        },
-        "importlib-metadata": {
-            "hashes": [
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-            "version": "==0.19"
-        },
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-            "version": "==7.7.0"
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-            "hashes": [
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-            "hashes": [
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-                "sha256:977c6583ae813a37dc1c2e1b715892461fcbdaa57f6fc62f33a528c4886c8f55"
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-            "version": "==2.0.9"
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-        "ptyprocess": {
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-                "sha256:923f299cc5ad920c68f2bc0bc98b75b9f838b93b599941a6b63ddbc2476394c0",
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-        "py": {
-            "hashes": [
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-        "pycodestyle": {
-            "hashes": [
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-                "sha256:e40a936c9a450ad81df37f549d676d127b1b66000a6c500caa2b085bc0ca976c"
-            ],
-            "version": "==2.5.0"
-        },
-        "pyflakes": {
-            "hashes": [
-                "sha256:17dbeb2e3f4d772725c777fabc446d5634d1038f234e77343108ce445ea69ce0",
-                "sha256:d976835886f8c5b31d47970ed689944a0262b5f3afa00a5a7b4dc81e5449f8a2"
-            ],
-            "version": "==2.1.1"
-        },
-        "pygments": {
-            "hashes": [
-                "sha256:71e430bc85c88a430f000ac1d9b331d2407f681d6f6aec95e8bcfbc3df5b0127",
-                "sha256:881c4c157e45f30af185c1ffe8d549d48ac9127433f2c380c24b84572ad66297"
-            ],
-            "version": "==2.4.2"
-        },
-        "pyparsing": {
-            "hashes": [
-                "sha256:6f98a7b9397e206d78cc01df10131398f1c8b8510a2f4d97d9abd82e1aacdd80",
-                "sha256:d9338df12903bbf5d65a0e4e87c2161968b10d2e489652bb47001d82a9b028b4"
-            ],
-            "version": "==2.4.2"
-        },
-        "pytest": {
-            "hashes": [
-                "sha256:6ef6d06de77ce2961156013e9dff62f1b2688aa04d0dc244299fe7d67e09370d",
-                "sha256:a736fed91c12681a7b34617c8fcefe39ea04599ca72c608751c31d89579a3f77"
-            ],
-            "index": "pypi",
-            "version": "==5.0.1"
-        },
-        "pytest-clarity": {
-            "hashes": [
-                "sha256:3f40d5ae7cb21cc95e622fc4f50d9466f80ae0f91460225b8c95c07afbf93e20"
-            ],
-            "index": "pypi",
-            "version": "==0.2.0a1"
-        },
-        "six": {
-            "hashes": [
-                "sha256:3350809f0555b11f552448330d0b52d5f24c91a322ea4a15ef22629740f3761c",
-                "sha256:d16a0141ec1a18405cd4ce8b4613101da75da0e9a7aec5bdd4fa804d0e0eba73"
-            ],
-            "version": "==1.12.0"
-        },
-        "termcolor": {
-            "hashes": [
-                "sha256:1d6d69ce66211143803fbc56652b41d73b4a400a2891d7bf7a1cdf4c02de613b"
-            ],
-            "version": "==1.1.0"
-        },
-        "traitlets": {
-            "hashes": [
-                "sha256:9c4bd2d267b7153df9152698efb1050a5d84982d3384a37b2c1f7723ba3e7835",
-                "sha256:c6cb5e6f57c5a9bdaa40fa71ce7b4af30298fbab9ece9815b5d995ab6217c7d9"
-            ],
-            "version": "==4.3.2"
-        },
-        "wcwidth": {
-            "hashes": [
-                "sha256:3df37372226d6e63e1b1e1eda15c594bca98a22d33a23832a90998faa96bc65e",
-                "sha256:f4ebe71925af7b40a864553f761ed559b43544f8f71746c2d756c7fe788ade7c"
-            ],
-            "version": "==0.1.7"
-        },
-        "zipp": {
-            "hashes": [
-                "sha256:4970c3758f4e89a7857a973b1e2a5d75bcdc47794442f2e2dd4fe8e0466e809a",
-                "sha256:8a5712cfd3bb4248015eb3b0b3c54a5f6ee3f2425963ef2a0125b8bc40aafaec"
-            ],
-            "version": "==0.5.2"
-        }
-    }
-}
--- a/README.md
+++ b/README.md
@ -1,31 +1,40 @@
-# CSV Metadata Quality [![Build Status](https://travis-ci.org/ilri/csv-metadata-quality.svg?branch=master)](https://travis-ci.org/ilri/csv-metadata-quality) [![builds.sr.ht status](https://builds.sr.ht/~alanorth/csv-metadata-quality.svg)](https://builds.sr.ht/~alanorth/csv-metadata-quality?)
-A simple, but opinionated metadata quality checker and fixer designed to work with CSVs in the DSpace ecosystem. The implementation is essentially a pipeline of checks and fixes that begins with splitting multi-value fields on the standard DSpace "||" separator, trimming leading/trailing whitespace, and then proceeding to more specialized cases like ISSNs, ISBNs, languages, etc.
+# DSpace CSV Metadata Quality Checker ![GitHub Actions](https://github.com/ilri/csv-metadata-quality/workflows/Build%20and%20Test/badge.svg) [![Build Status](https://ci.mjanja.ch/api/badges/alanorth/csv-metadata-quality/status.svg)](https://ci.mjanja.ch/alanorth/csv-metadata-quality)
+A simple, but opinionated metadata quality checker and fixer designed to work with CSVs in the DSpace ecosystem (though it could theoretically work on any CSV that uses Dublin Core fields as columns). The implementation is essentially a pipeline of checks and fixes that begins with splitting multi-value fields on the standard DSpace "||" separator, trimming leading/trailing whitespace, and then proceeding to more specialized cases like ISSNs, ISBNs, languages, unnecessary Unicode, AGROVOC terms, etc.

-Requires Python 3.6 or greater. CSV and Excel support comes from the [Pandas](https://pandas.pydata.org/) library, though your mileage may vary with Excel because this is much less tested.
+Requires Python 3.7.1 or greater (3.8+ recommended). CSV and Excel support comes from the [Pandas](https://pandas.pydata.org/) library, though your mileage may vary with Excel because this is much less tested.
+
+If you use the DSpace CSV metadata quality checker please cite:
+
+*Orth, A. 2019. DSpace CSV metadata quality checker. Nairobi, Kenya: ILRI. https://hdl.handle.net/10568/110997.*

 ## Functionality

 - Validate dates, ISSNs, ISBNs, and multi-value separators ("||")
- Validate languages against ISO 639-2 and ISO 639-3
+- Validate languages against ISO 639-1 (alpha2) and ISO 639-3 (alpha3)
+- Experimental validation of titles and abstracts against item's Dublin Core language field
 - Validate subjects against the AGROVOC REST API (see the `--agrovoc-fields` option)
+- Validation of licenses against the list of [SPDX license identifiers](https://spdx.org/licenses)
 - Fix leading, trailing, and excessive (ie, more than one) whitespace
- Fix invalid multi-value separators (`|`) using `--unsafe-fixes`
+- Fix invalid and unnecessary multi-value separators (`|`)
 - Fix problematic newlines (line feeds) using `--unsafe-fixes`
+- Perform [Unicode normalization](https://withblue.ink/2019/03/11/why-you-need-to-normalize-unicode-strings.html) on strings using `--unsafe-fixes`
 - Remove unnecessary Unicode like [non-breaking spaces](https://en.wikipedia.org/wiki/Non-breaking_space), [replacement characters](https://en.wikipedia.org/wiki/Specials_(Unicode_block)#Replacement_character), etc
 - Check for "suspicious" characters that indicate encoding or copy/paste issues, for example "foreˆt" should be "forêt"
+- Check for "mojibake" characters (and attempt to fix with `--unsafe-fixes`)
 - Remove duplicate metadata values
+- Check for duplicate items, using the title, type, and date issued as an indicator

 ## Installation
-The easiest way to install CSV Metadata Quality is with [pipenv](https://github.com/pypa/pipenv):
+The easiest way to install CSV Metadata Quality is with [poetry](https://python-poetry.org):

 ```
 $ git clone https://github.com/ilri/csv-metadata-quality.git
 $ cd csv-metadata-quality
-$ pipenv install
-$ pipenv shell
+$ poetry install
+$ poetry shell
 ```

-Otherwise, if you don't have pipenv, you can use a vanilla Python virtual environment:
+Otherwise, if you don't have poetry, you can use a vanilla Python virtual environment:

 ```
 $ git clone https://github.com/ilri/csv-metadata-quality.git
@ -48,15 +57,33 @@ To validate and clean a CSV file you must specify input and output files using t
 $ csv-metadata-quality -i data/test.csv -o /tmp/test.csv
 ```

-## Unsafe Fixes
-You can enable several "unsafe" fixes with the `--unsafe-fixes` option. Currently this will attempt to fix invalid multi-value separators and remove newlines.
+## Invalid Multi-Value Separators
+While it is *theoretically* possible for a single `|` character to be used legitimately in a metadata value, in my experience it is always a typo. For example, if a user mistakenly writes `Kenya|Tanzania` when attempting to indicate two countries, the result will be one metadata value with the literal text `Kenya|Tanzania`. This utility will correct the invalid multi-value separator so that there are two metadata values, ie `Kenya||Tanzania`.

-### Invalid Multi-Value Separators
-This is considered "unsafe" because it is *theoretically* possible for a single `|` character to be used legitimately in a metadata value, though in my experience it is always a typo. For example, if a user mistakenly writes `Kenya|Tanzania` when attempting to indicate two countries, the result will be one metadata value with the literal text `Kenya|Tanzania`. The `--unsafe-fixes` option will correct the invalid multi-value separator so that there are two metadata values, ie `Kenya||Tanzania`.
+This will also remove unnecessary trailing multi-value separators, for example `Kenya||Tanzania||`.
+
+## Unsafe Fixes
+You can enable several "unsafe" fixes with the `--unsafe-fixes` option. Currently this will remove newlines, perform Unicode normalization, and attempt to fix "mojibake" characters.

 ### Newlines
 This is considered "unsafe" because some systems give special importance to vertical space and render it properly. DSpace does not support rendering newlines in its XMLUI and has, at times, suffered from parsing errors that cause the import process to fail if an input file had newlines. The `--unsafe-fixes` option strips Unix line feeds (U+000A).

+### Unicode Normalization
+[Unicode](https://en.wikipedia.org/wiki/Unicode) is a standard for encoding text. As the standard aims to support most of the world's languages, characters can often be represented in different ways and still be valid Unicode. This leads to interesting problems that can be confusing unless you know what's going on behind the scenes. For example, the characters `é` and `é` *look* the same, but are not — technically they refer to different code points in the Unicode standard:
+
+- `é` is the Unicode code point `U+00E9`
+- `é` is the Unicode code points `U+0065` + `U+0301`
+
+Read more about [Unicode normalization](https://withblue.ink/2019/03/11/why-you-need-to-normalize-unicode-strings.html).
+
+### Encoding Issues aka "Mojibake"
+[Mojibake](https://en.wikipedia.org/wiki/Mojibake) is a phenomenon that occurs when text is decoded using an unintended character encoding. This usually presents itself in the form of strange, garbled characters in the text. Enabling "unsafe" fixes will attempt to correct these, for example:
+
+- CIAT PublicaÃ§ao → CIAT Publicaçao
+- CIAT PublicaciÃ³n → CIAT Publicación
+
+Pay special attention to the output of the script as well as the resulting file to make sure no new issues have been introduced. The ideal way to solve these issues is to avoid it in the first place. See [this guide about opening CSVs in UTF-8 format in Excel](https://www.itg.ias.edu/content/how-import-csv-file-uses-utf-8-character-encoding-0).
+
 ## AGROVOC Validation
 You can enable validation of metadata values in certain fields against the AGROVOC REST API with the `--agrovoc-fields` option. For example, in addition to agricultural subjects, many countries and regions are also present AGROVOC. Enable this validation by specifying a comma-separated list of fields:

@ -69,18 +96,36 @@ Invalid AGROVOC (cg.coverage.country): KENYAA

 *Note: Requests to the AGROVOC REST API are cached using [requests_cache](https://pypi.org/project/requests-cache/) to speed up subsequent runs with the same data and to be kind to the system's administrators.*

+## Experimental Checks
+You can enable experimental support for validating whether the value of an item's `dc.language.iso` or `dcterms.language` field matches the actual language used in its title, abstract, and citation.
+
+```
+$ csv-metadata-quality -i data/test.csv -o /tmp/test.csv -e
+...
+Possibly incorrect language es (detected en): Incorrect ISO 639-1 language
+Possibly incorrect language spa (detected eng): Incorrect ISO 639-3 language
+```
+
+This currently uses the [Python langid](https://github.com/saffsd/langid.py) library. In the future I would like to move to the fastText library, but there is currently an [issue with their Python bindings](https://github.com/facebookresearch/fastText/issues/909) that makes this unfeasible.
+
 ## Todo

 - Reporting / summary
 - Better logging, for example with INFO, WARN, and ERR levels
 - Verbose, debug, or quiet options
 - Warn if an author is shorter than 3 characters?
- Validate dc.rights field against SPDX? Perhaps with an option like `-m spdx` to enable the spdx module?
 - Validate DOIs? Normalize to https://doi.org format? Or use just the DOI part: 10.1016/j.worlddev.2010.06.006
 - Warn if two items use the same file in `filename` column
 - Add an option to drop invalid AGROVOC subjects?
- Add check for author names with incorrect spacing after commas, ie "Orth,Alan S."
 - Add tests for application invocation, ie `tests/test_app.py`?
+- Validate ISSNs or journal titles against CrossRef API?
+- Add configurable field validation, like specify a field name and a validation file?
+  - Perhaps like --validate=field.name,filename
+- Add some row-based item sanity checks and fixes:
+  - Warn if item is Open Access, but missing a filename or URL
+  - Warn if item is Open Access, but missing a license
+  - Warn if item has an ISSN but no journal title
+  - Update journal titles from ISSN

 ## License
 This work is licensed under the [GPLv3](https://www.gnu.org/licenses/gpl-3.0.en.html).
--- a/csv_metadata_quality/main.py
+++ b/csv_metadata_quality/main.py
@ -1,10 +1,13 @@
-from csv_metadata_quality import app
+# SPDX-License-Identifier: GPL-3.0-only
+
 from sys import argv

+from csv_metadata_quality import app
+

 def main():
    app.run(argv)


-if __name__ == '__main__':
+if __name__ == "__main__":
    main()
--- a/csv_metadata_quality/app.py
+++ b/csv_metadata_quality/app.py
@ -1,21 +1,57 @@
-from csv_metadata_quality.version import VERSION
+# SPDX-License-Identifier: GPL-3.0-only
+
 import argparse
-import csv_metadata_quality.check as check
-import csv_metadata_quality.fix as fix
-import pandas as pd
 import re
 import signal
 import sys

+import pandas as pd
+from colorama import Fore
+
+import csv_metadata_quality.check as check
+import csv_metadata_quality.experimental as experimental
+import csv_metadata_quality.fix as fix
+from csv_metadata_quality.version import VERSION
+

 def parse_args(argv):
-    parser = argparse.ArgumentParser(description='Metadata quality checker and fixer.')
-    parser.add_argument('--agrovoc-fields', '-a', help='Comma-separated list of fields to validate against AGROVOC, for example: dc.subject,cg.coverage.country')
-    parser.add_argument('--input-file', '-i', help='Path to input file. Can be UTF-8 CSV or Excel XLSX.', required=True, type=argparse.FileType('r', encoding='UTF-8'))
-    parser.add_argument('--output-file', '-o', help='Path to output file (always CSV).', required=True, type=argparse.FileType('w', encoding='UTF-8'))
-    parser.add_argument('--unsafe-fixes', '-u', help='Perform unsafe fixes.', action='store_true')
-    parser.add_argument('--version', '-V', action='version', version=f'CSV Metadata Quality v{VERSION}')
-    parser.add_argument('--exclude-fields', '-x', help='Comma-separated list of fields to skip, for example: dc.contributor.author,dc.identifier.citation')
+    parser = argparse.ArgumentParser(description="Metadata quality checker and fixer.")
+    parser.add_argument(
+        "--agrovoc-fields",
+        "-a",
+        help="Comma-separated list of fields to validate against AGROVOC, for example: dcterms.subject,cg.coverage.country",
+    )
+    parser.add_argument(
+        "--experimental-checks",
+        "-e",
+        help="Enable experimental checks like language detection",
+        action="store_true",
+    )
+    parser.add_argument(
+        "--input-file",
+        "-i",
+        help="Path to input file. Can be UTF-8 CSV or Excel XLSX.",
+        required=True,
+        type=argparse.FileType("r", encoding="UTF-8"),
+    )
+    parser.add_argument(
+        "--output-file",
+        "-o",
+        help="Path to output file (always CSV).",
+        required=True,
+        type=argparse.FileType("w", encoding="UTF-8"),
+    )
+    parser.add_argument(
+        "--unsafe-fixes", "-u", help="Perform unsafe fixes.", action="store_true"
+    )
+    parser.add_argument(
+        "--version", "-V", action="version", version=f"CSV Metadata Quality v{VERSION}"
+    )
+    parser.add_argument(
+        "--exclude-fields",
+        "-x",
+        help="Comma-separated list of fields to skip, for example: dc.contributor.author,dcterms.bibliographicCitation",
+    )
    args = parser.parse_args()

    return args
@ -34,22 +70,22 @@ def run(argv):
    # Read all fields as strings so dates don't get converted from 1998 to 1998.0
    df = pd.read_csv(args.input_file, dtype=str)

-    for column in df.columns.values.tolist():
+    for column in df.columns:
        # Check if the user requested to skip any fields
        if args.exclude_fields:
            skip = False
            # Split the list of excludes on ',' so we can test exact matches
            # rather than fuzzy matches with regexes or "if word in string"
-            for exclude in args.exclude_fields.split(','):
+            for exclude in args.exclude_fields.split(","):
                if column == exclude and skip is False:
                    skip = True
            if skip:
-                print(f'Skipping {column}')
+                print(f"{Fore.YELLOW}Skipping {Fore.RESET}{column}")

                continue

        # Fix: whitespace
-        df[column] = df[column].apply(fix.whitespace)
+        df[column] = df[column].apply(fix.whitespace, field_name=column)

        # Fix: newlines
        if args.unsafe_fixes:
@ -58,58 +94,104 @@ def run(argv):
        # Fix: missing space after comma. Only run on author and citation
        # fields for now, as this problem is mostly an issue in names.
        if args.unsafe_fixes:
-            match = re.match(r'^.*?(author|citation).*$', column)
+            match = re.match(r"^.*?(author|citation).*$", column)
            if match is not None:
                df[column] = df[column].apply(fix.comma_space, field_name=column)

+        # Fix: perform Unicode normalization (NFC) to convert decomposed
+        # characters into their canonical forms.
+        if args.unsafe_fixes:
+            df[column] = df[column].apply(fix.normalize_unicode, field_name=column)
+
        # Fix: unnecessary Unicode
        df[column] = df[column].apply(fix.unnecessary_unicode)

-        # Check: invalid multi-value separator
-        df[column] = df[column].apply(check.separators)
-
        # Check: suspicious characters
-        df[column] = df[column].apply(check.suspicious_characters, field_name=column)
+        df[column].apply(check.suspicious_characters, field_name=column)

-        # Fix: invalid multi-value separator
+        # Check: mojibake
+        df[column].apply(check.mojibake, field_name=column)
+
+        # Fix: mojibake
        if args.unsafe_fixes:
-            df[column] = df[column].apply(fix.separators)
-            # Run whitespace fix again after fixing invalid separators
-            df[column] = df[column].apply(fix.whitespace)
+            df[column] = df[column].apply(fix.mojibake, field_name=column)
+
+        # Fix: invalid and unnecessary multi-value separators
+        df[column] = df[column].apply(fix.separators, field_name=column)
+        # Run whitespace fix again after fixing invalid separators
+        df[column] = df[column].apply(fix.whitespace, field_name=column)

        # Fix: duplicate metadata values
-        df[column] = df[column].apply(fix.duplicates)
+        df[column] = df[column].apply(fix.duplicates, field_name=column)

        # Check: invalid AGROVOC subject
        if args.agrovoc_fields:
            # Identify fields the user wants to validate against AGROVOC
-            for field in args.agrovoc_fields.split(','):
+            for field in args.agrovoc_fields.split(","):
                if column == field:
-                    df[column] = df[column].apply(check.agrovoc, field_name=column)
+                    df[column].apply(check.agrovoc, field_name=column)

        # Check: invalid language
-        match = re.match(r'^.*?language.*$', column)
+        match = re.match(r"^.*?language.*$", column)
        if match is not None:
-            df[column] = df[column].apply(check.language)
+            df[column].apply(check.language)

        # Check: invalid ISSN
-        match = re.match(r'^.*?issn.*$', column)
+        match = re.match(r"^.*?issn.*$", column)
        if match is not None:
-            df[column] = df[column].apply(check.issn)
+            df[column].apply(check.issn)

        # Check: invalid ISBN
-        match = re.match(r'^.*?isbn.*$', column)
+        match = re.match(r"^.*?isbn.*$", column)
        if match is not None:
-            df[column] = df[column].apply(check.isbn)
+            df[column].apply(check.isbn)

        # Check: invalid date
-        match = re.match(r'^.*?date.*$', column)
+        match = re.match(r"^.*?(date|dcterms\.issued).*$", column)
        if match is not None:
-            df[column] = df[column].apply(check.date, field_name=column)
+            df[column].apply(check.date, field_name=column)

        # Check: filename extension
-        if column == 'filename':
-            df[column] = df[column].apply(check.filename_extension)
+        if column == "filename":
+            df[column].apply(check.filename_extension)
+
+        # Check: SPDX license identifier
+        match = re.match(r"dcterms\.license.*$", column)
+        if match is not None:
+            df[column].apply(check.spdx_license_identifier)
+
+    ### End individual column checks ###
+
+    # Check: duplicate items
+    # We extract just the title, type, and date issued columns to analyze
+    try:
+        duplicates_df = df.filter(
+            regex=r"dcterms\.title|dc\.title|dcterms\.type|dc\.type|dcterms\.issued|dc\.date\.issued"
+        )
+        check.duplicate_items(duplicates_df)
+
+        # Delete the temporary duplicates DataFrame
+        del duplicates_df
+    except IndexError:
+        pass
+
+    ##
+    # Perform some checks on rows so we can consider items as a whole rather
+    # than simple on a field-by-field basis. This allows us to check whether
+    # the language used in the title and abstract matches the language indi-
+    # cated in the language field, for example.
+    #
+    # This is slower and apparently frowned upon in the Pandas community be-
+    # cause it requires iterating over rows rather than using apply over a
+    # column. For now it will have to do.
+    ##
+
+    if args.experimental_checks:
+        # Transpose the DataFrame so we can consider each row as a column
+        df_transposed = df.T
+
+        for column in df_transposed.columns:
+            experimental.correct_language(df_transposed[column])

    # Write
    df.to_csv(args.output_file, index=False)
--- a/csv_metadata_quality/check.py
+++ b/csv_metadata_quality/check.py
@ -1,4 +1,19 @@
+# SPDX-License-Identifier: GPL-3.0-only
+
+import os
+import re
+from datetime import datetime, timedelta
+
 import pandas as pd
+import requests
+import requests_cache
+import spdx_license_list
+from colorama import Fore
+from pycountry import languages
+from stdnum import isbn as stdnum_isbn
+from stdnum import issn as stdnum_issn
+
+from csv_metadata_quality.util import is_mojibake


 def issn(field):
@ -11,19 +26,17 @@ def issn(field):
    See: https://arthurdejong.org/python-stdnum/doc/1.11/index.html#stdnum.module.is_valid
    """

-    from stdnum import issn
-
    # Skip fields with missing values
    if pd.isna(field):
        return

    # Try to split multi-value field on "||" separator
-    for value in field.split('||'):
+    for value in field.split("||"):

-        if not issn.is_valid(value):
-            print(f'Invalid ISSN: {value}')
+        if not stdnum_issn.is_valid(value):
+            print(f"{Fore.RED}Invalid ISSN: {Fore.RESET}{value}")

-    return field
+    return


 def isbn(field):
@ -36,43 +49,17 @@ def isbn(field):
    See: https://arthurdejong.org/python-stdnum/doc/1.11/index.html#stdnum.module.is_valid
    """

-    from stdnum import isbn
-
    # Skip fields with missing values
    if pd.isna(field):
        return

    # Try to split multi-value field on "||" separator
-    for value in field.split('||'):
+    for value in field.split("||"):

-        if not isbn.is_valid(value):
-            print(f'Invalid ISBN: {value}')
+        if not stdnum_isbn.is_valid(value):
+            print(f"{Fore.RED}Invalid ISBN: {Fore.RESET}{value}")

-    return field
-
-
-def separators(field):
-    """Check for invalid multi-value separators (ie "|" or "|||").
-
-    Prints the field with the invalid multi-value separator.
-    """
-
-    import re
-
-    # Skip fields with missing values
-    if pd.isna(field):
-        return
-
-    # Try to split multi-value field on "||" separator
-    for value in field.split('||'):
-
-        # After splitting, see if there are any remaining "|" characters
-        match = re.findall(r'^.*?\|.*$', value)
-
-        if match:
-            print(f'Invalid multi-value separator: {field}')
-
-    return field
+    return


 def date(field, field_name):
@ -85,47 +72,56 @@ def date(field, field_name):

    Prints the date if invalid.
    """
-    from datetime import datetime

    if pd.isna(field):
-        print(f'Missing date ({field_name}).')
+        print(f"{Fore.RED}Missing date ({field_name}).{Fore.RESET}")

        return

    # Try to split multi-value field on "||" separator
-    multiple_dates = field.split('||')
+    multiple_dates = field.split("||")

    # We don't allow multi-value date fields
    if len(multiple_dates) > 1:
-        print(f'Multiple dates not allowed ({field_name}): {field}')
+        print(
+            f"{Fore.RED}Multiple dates not allowed ({field_name}): {Fore.RESET}{field}"
+        )

-        return field
+        return

    try:
        # Check if date is valid YYYY format
-        datetime.strptime(field, '%Y')
+        datetime.strptime(field, "%Y")

-        return field
+        return
    except ValueError:
        pass

    try:
        # Check if date is valid YYYY-MM format
-        datetime.strptime(field, '%Y-%m')
+        datetime.strptime(field, "%Y-%m")

-        return field
+        return
    except ValueError:
        pass

    try:
        # Check if date is valid YYYY-MM-DD format
-        datetime.strptime(field, '%Y-%m-%d')
+        datetime.strptime(field, "%Y-%m-%d")

-        return field
+        return
    except ValueError:
-        print(f'Invalid date ({field_name}): {field}')
+        pass

-        return field
+    try:
+        # Check if date is valid YYYY-MM-DDTHH:MM:SSZ format
+        datetime.strptime(field, "%Y-%m-%dT%H:%M:%SZ")
+
+        return
+    except ValueError:
+        print(f"{Fore.RED}Invalid date ({field_name}): {Fore.RESET}{field}")
+
+        return


 def suspicious_characters(field, field_name):
@ -140,7 +136,7 @@ def suspicious_characters(field, field_name):
        return

    # List of suspicious characters, for example:  ́ˆ~`
-    suspicious_characters = ['\u00B4', '\u02C6', '\u007E', '\u0060']
+    suspicious_characters = ["\u00B4", "\u02C6", "\u007E", "\u0060"]

    for character in suspicious_characters:
        # Find the position of the suspicious character in the string
@ -156,20 +152,18 @@ def suspicious_characters(field, field_name):
            # character and spanning enough of the rest to give a preview,
            # but not too much to cause the line to break in terminals with
            # a default of 80 characters width.
-            suspicious_character_msg = f'Suspicious character ({field_name}): {field_subset}'
-            print(f'{suspicious_character_msg:1.80}')
+            suspicious_character_msg = f"{Fore.YELLOW}Suspicious character ({field_name}): {Fore.RESET}{field_subset}"
+            print(f"{suspicious_character_msg:1.80}")

-    return field
+    return


 def language(field):
-    """Check if a language is valid ISO 639-2 or ISO 639-3.
+    """Check if a language is valid ISO 639-1 (alpha 2) or ISO 639-3 (alpha 3).

    Prints the value if it is invalid.
    """

-    from pycountry import languages
-
    # Skip fields with missing values
    if pd.isna(field):
        return
@ -177,24 +171,20 @@ def language(field):
    # need to handle "Other" values here...

    # Try to split multi-value field on "||" separator
-    for value in field.split('||'):
+    for value in field.split("||"):

        # After splitting, check if language value is 2 or 3 characters so we
-        # can check it against ISO 639-2 or ISO 639-3 accordingly.
+        # can check it against ISO 639-1 or ISO 639-3 accordingly.
        if len(value) == 2:
            if not languages.get(alpha_2=value):
-                print(f'Invalid ISO 639-2 language: {value}')
-
-                pass
+                print(f"{Fore.RED}Invalid ISO 639-1 language: {Fore.RESET}{value}")
        elif len(value) == 3:
            if not languages.get(alpha_3=value):
-                print(f'Invalid ISO 639-3 language: {value}')
-
-                pass
+                print(f"{Fore.RED}Invalid ISO 639-3 language: {Fore.RESET}{value}")
        else:
-            print(f'Invalid language: {value}')
+            print(f"{Fore.RED}Invalid language: {Fore.RESET}{value}")

-    return field
+    return


 def agrovoc(field, field_name):
@ -211,35 +201,38 @@ def agrovoc(field, field_name):
    Prints a warning if the value is invalid.
    """

-    from datetime import timedelta
-    import requests
-    import requests_cache
-
    # Skip fields with missing values
    if pd.isna(field):
        return

+    # enable transparent request cache with thirty days expiry
+    expire_after = timedelta(days=30)
+    # Allow overriding the location of the requests cache, just in case we are
+    # running in an environment where we can't write to the current working di-
+    # rectory (for example from csv-metadata-quality-web).
+    REQUESTS_CACHE_DIR = os.environ.get("REQUESTS_CACHE_DIR", ".")
+    requests_cache.install_cache(
+        f"{REQUESTS_CACHE_DIR}/agrovoc-response-cache", expire_after=expire_after
+    )
+
+    # prune old cache entries
+    requests_cache.remove_expired_responses()
+
    # Try to split multi-value field on "||" separator
-    for value in field.split('||'):
-        request_url = f'http://agrovoc.uniroma2.it/agrovoc/rest/v1/agrovoc/search?query={value}'
+    for value in field.split("||"):
+        request_url = "http://agrovoc.uniroma2.it/agrovoc/rest/v1/agrovoc/search"
+        request_params = {"query": value}

-        # enable transparent request cache with thirty days expiry
-        expire_after = timedelta(days=30)
-        requests_cache.install_cache('agrovoc-response-cache', expire_after=expire_after)
-
-        request = requests.get(request_url)
-
-        # prune old cache entries
-        requests_cache.core.remove_expired_responses()
+        request = requests.get(request_url, params=request_params)

        if request.status_code == requests.codes.ok:
            data = request.json()

            # check if there are any results
-            if len(data['results']) == 0:
-                print(f'Invalid AGROVOC ({field_name}): {value}')
+            if len(data["results"]) == 0:
+                print(f"{Fore.RED}Invalid AGROVOC ({field_name}): {Fore.RESET}{value}")

-    return field
+    return


 def filename_extension(field):
@ -253,17 +246,23 @@ def filename_extension(field):
    than .pdf, .xls(x), .doc(x), ppt(x), case insensitive).
    """

-    import re
-
    # Skip fields with missing values
    if pd.isna(field):
        return

    # Try to split multi-value field on "||" separator
-    values = field.split('||')
+    values = field.split("||")

    # List of common filename extentions
-    common_filename_extensions = ['.pdf', '.doc', '.docx', '.ppt', '.pptx', '.xls', '.xlsx']
+    common_filename_extensions = [
+        ".pdf",
+        ".doc",
+        ".docx",
+        ".ppt",
+        ".pptx",
+        ".xls",
+        ".xlsx",
+    ]

    # Iterate over all values
    for value in values:
@ -272,7 +271,7 @@ def filename_extension(field):

        for filename_extension in common_filename_extensions:
            # Check for extension at the end of the filename
-            pattern = re.escape(filename_extension) + r'$'
+            pattern = re.escape(filename_extension) + r"$"
            match = re.search(pattern, value, re.IGNORECASE)

            if match is not None:
@ -282,6 +281,84 @@ def filename_extension(field):
                break

        if filename_extension_match is False:
-            print(f'Filename with uncommon extension: {value}')
+            print(f"{Fore.YELLOW}Filename with uncommon extension: {Fore.RESET}{value}")

-    return field
+    return
+
+
+def spdx_license_identifier(field):
+    """Check if a license is a valid SPDX identifier.
+
+    Prints the value if it is invalid.
+    """
+
+    # Skip fields with missing values
+    if pd.isna(field):
+        return
+
+    # Try to split multi-value field on "||" separator
+    for value in field.split("||"):
+        if value not in spdx_license_list.LICENSES:
+            print(f"{Fore.YELLOW}Non-SPDX license identifier: {Fore.RESET}{value}")
+
+    return
+
+
+def duplicate_items(df):
+    """Attempt to identify duplicate items.
+
+    First we check the total number of titles and compare it with the number of
+    unique titles. If there are less unique titles than total titles we expand
+    the search by creating a key (of sorts) for each item that includes their
+    title, type, and date issued, and compare it with all the others. If there
+    are multiple occurrences of the same title, type, date string then it's a
+    very good indicator that the items are duplicates.
+    """
+
+    # Extract the names of the title, type, and date issued columns so we can
+    # reference them later. First we filter columns by likely patterns, then
+    # we extract the name from the first item of the resulting object, ie:
+    #
+    #   Index(['dcterms.title[en_US]'], dtype='object')
+    #
+    title_column_name = df.filter(regex=r"dcterms\.title|dc\.title").columns[0]
+    type_column_name = df.filter(regex=r"dcterms\.title|dc\.title").columns[0]
+    date_column_name = df.filter(
+        regex=r"dcterms\.issued|dc\.date\.accessioned"
+    ).columns[0]
+
+    items_count_total = df[title_column_name].count()
+    items_count_unique = df[title_column_name].nunique()
+
+    if items_count_unique < items_count_total:
+        # Create a list to hold our items while we check for duplicates
+        items = list()
+
+        for index, row in df.iterrows():
+            item_title_type_date = f"{row[title_column_name]}{row[type_column_name]}{row[date_column_name]}"
+
+            if item_title_type_date in items:
+                print(
+                    f"{Fore.YELLOW}Possible duplicate ({title_column_name}): {Fore.RESET}{row[title_column_name]}"
+                )
+            else:
+                items.append(item_title_type_date)
+
+
+def mojibake(field, field_name):
+    """Check for mojibake (text that was encoded in one encoding and decoded in
+    in another, perhaps multiple times). See util.py.
+
+    Prints the string if it contains suspected mojibake.
+    """
+
+    # Skip fields with missing values
+    if pd.isna(field):
+        return
+
+    if is_mojibake(field):
+        print(
+            f"{Fore.YELLOW}Possible encoding issue ({field_name}): {Fore.RESET}{field}"
+        )
+
+    return
--- a/csv_metadata_quality/experimental.py
+++ b/csv_metadata_quality/experimental.py
@ -0,0 +1,98 @@
+# SPDX-License-Identifier: GPL-3.0-only
+
+import re
+
+import langid
+import pandas as pd
+from colorama import Fore
+from pycountry import languages
+
+
+def correct_language(row):
+    """Analyze the text used in the title, abstract, and citation fields to pre-
+    dict the language being used and compare it with the item's dc.language.iso
+    field.
+
+    Function prints an error if the language field does not match the detected
+    language and returns the value in the language field if it does match.
+    """
+
+    # Initialize some variables at global scope so that we can set them in the
+    # loop scope below and still be able to access them afterwards.
+    language = ""
+    sample_strings = list()
+    title = None
+
+    # Iterate over the labels of the current row's values. Before we transposed
+    # the DataFrame these were the columns in the CSV, ie dc.title and dc.type.
+    for label in row.axes[0]:
+        # Skip fields with missing values
+        if pd.isna(row[label]):
+            continue
+
+        # Check if current row has multiple language values (separated by "||")
+        match = re.match(r"^.*?language.*$", label)
+        if match is not None:
+            # Skip fields with multiple language values
+            if "||" in row[label]:
+                return
+
+            language = row[label]
+
+        # Extract title if it is present
+        match = re.match(r"^.*?title.*$", label)
+        if match is not None:
+            title = row[label]
+            # Append title to sample strings
+            sample_strings.append(row[label])
+
+        # Extract abstract if it is present
+        match = re.match(r"^.*?abstract.*$", label)
+        if match is not None:
+            sample_strings.append(row[label])
+
+        # Extract citation if it is present
+        match = re.match(r"^.*?citation.*$", label)
+        if match is not None:
+            sample_strings.append(row[label])
+
+    # Make sure language is not blank and is valid ISO 639-1/639-3 before proceeding with language prediction
+    if language != "":
+        # Check language value like "es"
+        if len(language) == 2:
+            if not languages.get(alpha_2=language):
+                return
+        # Check language value like "spa"
+        elif len(language) == 3:
+            if not languages.get(alpha_3=language):
+                return
+        # Language value is something else like "Span", do not proceed
+        else:
+            return
+    # Language is blank, do not proceed
+    else:
+        return
+
+    # Concatenate all sample strings into one string
+    sample_text = " ".join(sample_strings)
+
+    # Restrict the langid detection space to reduce false positives
+    langid.set_languages(
+        ["ar", "de", "en", "es", "fr", "hi", "it", "ja", "ko", "pt", "ru", "vi", "zh"]
+    )
+    langid_classification = langid.classify(sample_text)
+
+    # langid returns an ISO 639-1 (alpha 2) representation of the detected language, but the current item's language field might be ISO 639-3 (alpha 3) so we should use a pycountry Language object to compare both represenations and give appropriate error messages that match the format used by in the input file.
+    detected_language = languages.get(alpha_2=langid_classification[0])
+    if len(language) == 2 and language != detected_language.alpha_2:
+        print(
+            f"{Fore.YELLOW}Possibly incorrect language {language} (detected {detected_language.alpha_2}): {Fore.RESET}{title}"
+        )
+
+    elif len(language) == 3 and language != detected_language.alpha_3:
+        print(
+            f"{Fore.YELLOW}Possibly incorrect language {language} (detected {detected_language.alpha_3}): {Fore.RESET}{title}"
+        )
+
+    else:
+        return
--- a/csv_metadata_quality/fix.py
+++ b/csv_metadata_quality/fix.py
@ -1,8 +1,16 @@
-import pandas as pd
+# SPDX-License-Identifier: GPL-3.0-only
+
 import re
+from unicodedata import normalize
+
+import pandas as pd
+from colorama import Fore
+from ftfy import fix_text
+
+from csv_metadata_quality.util import is_mojibake, is_nfc


-def whitespace(field):
+def whitespace(field, field_name):
    """Fix whitespace issues.

    Return string with leading, trailing, and consecutive whitespace trimmed.
@ -16,29 +24,38 @@ def whitespace(field):
    values = list()

    # Try to split multi-value field on "||" separator
-    for value in field.split('||'):
+    for value in field.split("||"):
        # Strip leading and trailing whitespace
        value = value.strip()

        # Replace excessive whitespace (>2) with one space
-        pattern = re.compile(r'\s{2,}')
+        pattern = re.compile(r"\s{2,}")
        match = re.findall(pattern, value)

        if match:
-            print(f'Excessive whitespace: {value}')
-            value = re.sub(pattern, ' ', value)
+            print(
+                f"{Fore.GREEN}Removing excessive whitespace ({field_name}): {Fore.RESET}{value}"
+            )
+            value = re.sub(pattern, " ", value)

        # Save cleaned value
        values.append(value)

    # Create a new field consisting of all values joined with "||"
-    new_field = '||'.join(values)
+    new_field = "||".join(values)

    return new_field


-def separators(field):
-    """Fix for invalid multi-value separators (ie "|")."""
+def separators(field, field_name):
+    """Fix for invalid and unnecessary multi-value separators, for example:
+
+        value|value
+        value|||value
+        value||value||
+
+    Prints the field with the invalid multi-value separator.
+    """

    # Skip fields with missing values
    if pd.isna(field):
@ -48,21 +65,31 @@ def separators(field):
    values = list()

    # Try to split multi-value field on "||" separator
-    for value in field.split('||'):
+    for value in field.split("||"):
+        # Check if the value is blank and skip it
+        if value == "":
+            print(
+                f"{Fore.GREEN}Fixing unnecessary multi-value separator ({field_name}): {Fore.RESET}{field}"
+            )
+
+            continue
+
        # After splitting, see if there are any remaining "|" characters
-        pattern = re.compile(r'\|')
+        pattern = re.compile(r"\|")
        match = re.findall(pattern, value)

        if match:
-            print(f'Fixing invalid multi-value separator: {value}')
+            print(
+                f"{Fore.GREEN}Fixing invalid multi-value separator ({field_name}): {Fore.RESET}{value}"
+            )

-            value = re.sub(pattern, '||', value)
+            value = re.sub(pattern, "||", value)

        # Save cleaned value
        values.append(value)

    # Create a new field consisting of all values joined with "||"
-    new_field = '||'.join(values)
+    new_field = "||".join(values)

    return new_field

@ -73,10 +100,10 @@ def unnecessary_unicode(field):
    Removes unnecessary Unicode characters like:
        - Zero-width space (U+200B)
        - Replacement character (U+FFFD)
-        - No-break space (U+00A0)

    Replaces unnecessary Unicode characters like:
        - Soft hyphen (U+00AD) → hyphen
+        - No-break space (U+00A0) → space

    Return string with characters removed or replaced.
    """
@ -86,41 +113,45 @@ def unnecessary_unicode(field):
        return

    # Check for zero-width space characters (U+200B)
-    pattern = re.compile(r'\u200B')
+    pattern = re.compile(r"\u200B")
    match = re.findall(pattern, field)

    if match:
-        print(f'Removing unnecessary Unicode (U+200B): {field}')
-        field = re.sub(pattern, '', field)
+        print(f"{Fore.GREEN}Removing unnecessary Unicode (U+200B): {Fore.RESET}{field}")
+        field = re.sub(pattern, "", field)

    # Check for replacement characters (U+FFFD)
-    pattern = re.compile(r'\uFFFD')
+    pattern = re.compile(r"\uFFFD")
    match = re.findall(pattern, field)

    if match:
-        print(f'Removing unnecessary Unicode (U+FFFD): {field}')
-        field = re.sub(pattern, '', field)
+        print(f"{Fore.GREEN}Removing unnecessary Unicode (U+FFFD): {Fore.RESET}{field}")
+        field = re.sub(pattern, "", field)

    # Check for no-break spaces (U+00A0)
-    pattern = re.compile(r'\u00A0')
+    pattern = re.compile(r"\u00A0")
    match = re.findall(pattern, field)

    if match:
-        print(f'Removing unnecessary Unicode (U+00A0): {field}')
-        field = re.sub(pattern, '', field)
+        print(
+            f"{Fore.GREEN}Replacing unnecessary Unicode (U+00A0): {Fore.RESET}{field}"
+        )
+        field = re.sub(pattern, " ", field)

    # Check for soft hyphens (U+00AD), sometimes preceeded with a normal hyphen
-    pattern = re.compile(r'\u002D*?\u00AD')
+    pattern = re.compile(r"\u002D*?\u00AD")
    match = re.findall(pattern, field)

    if match:
-        print(f'Replacing unnecessary Unicode (U+00AD): {field}')
-        field = re.sub(pattern, '-', field)
+        print(
+            f"{Fore.GREEN}Replacing unnecessary Unicode (U+00AD): {Fore.RESET}{field}"
+        )
+        field = re.sub(pattern, "-", field)

    return field


-def duplicates(field):
+def duplicates(field, field_name):
    """Remove duplicate metadata values."""

    # Skip fields with missing values
@ -128,7 +159,7 @@ def duplicates(field):
        return

    # Try to split multi-value field on "||" separator
-    values = field.split('||')
+    values = field.split("||")

    # Initialize an empty list to hold the de-duplicated values
    new_values = list()
@ -139,10 +170,12 @@ def duplicates(field):
        if value not in new_values:
            new_values.append(value)
        else:
-            print(f'Dropping duplicate value: {value}')
+            print(
+                f"{Fore.GREEN}Removing duplicate value ({field_name}): {Fore.RESET}{value}"
+            )

    # Create a new field consisting of all values joined with "||"
-    new_field = '||'.join(new_values)
+    new_field = "||".join(new_values)

    return new_field

@ -169,11 +202,11 @@ def newlines(field):
        return

    # Check for Unix line feed (LF)
-    match = re.findall(r'\n', field)
+    match = re.findall(r"\n", field)

    if match:
-        print(f'Removing newline: {field}')
-        field = field.replace('\n', '')
+        print(f"{Fore.GREEN}Removing newline: {Fore.RESET}{field}")
+        field = field.replace("\n", "")

    return field

@ -193,10 +226,52 @@ def comma_space(field, field_name):
        return

    # Check for comma followed by a word character
-    match = re.findall(r',\w', field)
+    match = re.findall(r",\w", field)

    if match:
-        print(f'Adding space after comma ({field_name}): {field}')
-        field = re.sub(r',(\w)', r', \1', field)
+        print(
+            f"{Fore.GREEN}Adding space after comma ({field_name}): {Fore.RESET}{field}"
+        )
+        field = re.sub(r",(\w)", r", \1", field)

    return field
+
+
+def normalize_unicode(field, field_name):
+    """Fix occurrences of decomposed Unicode characters by normalizing them
+    with NFC to their canonical forms, for example:
+
+    Ouédraogo, Mathieu → Ouédraogo, Mathieu
+
+    Return normalized string.
+    """
+
+    # Skip fields with missing values
+    if pd.isna(field):
+        return
+
+    # Check if the current string is using normalized Unicode (NFC)
+    if not is_nfc(field):
+        print(f"{Fore.GREEN}Normalizing Unicode ({field_name}): {Fore.RESET}{field}")
+        field = normalize("NFC", field)
+
+    return field
+
+
+def mojibake(field, field_name):
+    """Attempts to fix mojibake (text that was encoded in one encoding and deco-
+    ded in another, perhaps multiple times). See util.py.
+
+    Return fixed string.
+    """
+
+    # Skip fields with missing values
+    if pd.isna(field):
+        return field
+
+    if is_mojibake(field):
+        print(f"{Fore.GREEN}Fixing encoding issue ({field_name}): {Fore.RESET}{field}")
+
+        return fix_text(field)
+    else:
+        return field
--- a/csv_metadata_quality/util.py
+++ b/csv_metadata_quality/util.py
@ -0,0 +1,51 @@
+# SPDX-License-Identifier: GPL-3.0-only
+
+from ftfy.badness import sequence_weirdness
+
+
+def is_nfc(field):
+    """Utility function to check whether a string is using normalized Unicode.
+    Python's built-in unicodedata library has the is_normalized() function, but
+    it was only introduced in Python 3.8. By using a simple utility function we
+    are able to run on Python >= 3.6 again.
+
+    See: https://docs.python.org/3/library/unicodedata.html
+
+    Return boolean.
+    """
+
+    from unicodedata import normalize
+
+    return field == normalize("NFC", field)
+
+
+def is_mojibake(field):
+    """Determines whether a string contains mojibake.
+
+    We commonly deal with CSV files that were *encoded* in UTF-8, but decoded
+    as something else like CP-1252 (Windows Latin). This manifests in the form
+    of "mojibake", for example:
+
+        - CIAT PublicaÃ§ao
+        - CIAT PublicaciÃ³n
+
+    This uses the excellent "fixes text for you" (ftfy) library to determine
+    whether a string contains characters that have been encoded in one encoding
+    and decoded in another.
+
+    Inspired by this code snippet from Martijn Pieters on StackOverflow:
+    https://stackoverflow.com/questions/29071995/identify-garbage-unicode-string-using-python
+
+    Return boolean.
+    """
+    if not sequence_weirdness(field):
+        # Nothing weird, should be okay
+        return False
+    try:
+        field.encode("sloppy-windows-1252")
+    except UnicodeEncodeError:
+        # Not CP-1252 encodable, probably fine
+        return False
+    else:
+        # Encodable as CP-1252, Mojibake alert level high
+        return True
--- a/csv_metadata_quality/version.py
+++ b/csv_metadata_quality/version.py
@ -1 +1,3 @@
-VERSION = '0.2.2'
+# SPDX-License-Identifier: GPL-3.0-only
+
+VERSION = "0.4.8-dev"
--- a/data/test.csv
+++ b/data/test.csv
@ -1,26 +1,35 @@
-dc.contributor.author,birthdate,dc.identifier.issn,dc.identifier.isbn,dc.language.iso,dc.subject,cg.coverage.country,filename
- Leading space,2019-07-29,,,,,,
-Trailing space ,2019-07-29,,,,,,
-Excessive  space,2019-07-29,,,,,,
-Miscellaenous ||whitespace | issues ,2019-07-29,,,,,,
-Duplicate||Duplicate,2019-07-29,,,,,,
-Invalid ISSN,2019-07-29,2321-2302,,,,,
-Invalid ISBN,2019-07-29,,978-0-306-40615-6,,,,
-Multiple valid ISSNs,2019-07-29,0378-5955||0024-9319,,,,,
-Multiple valid ISBNs,2019-07-29,,99921-58-10-7||978-0-306-40615-7,,,,
-Invalid date,2019-07-260,,,,,,
-Multiple dates,2019-07-26||2019-01-10,,,,,,
-Invalid multi-value separator,2019-07-29,0378-5955|0024-9319,,,,,
-Unnecessary Unicode,2019-07-29,,,,,,
-Suspicious character||foreˆt,2019-07-29,,,,,,
-Invalid ISO 639-2 language,2019-07-29,,,jp,,,
-Invalid ISO 639-3 language,2019-07-29,,,chi,,,
-Invalid language,2019-07-29,,,Span,,,
-Invalid AGROVOC subject,2019-07-29,,,,FOREST,,
+dc.title,dcterms.issued,dc.identifier.issn,dc.identifier.isbn,dcterms.language,dcterms.subject,cg.coverage.country,filename,dcterms.license,dcterms.type
+ Leading space,2019-07-29,,,,,,,,
+Trailing space ,2019-07-29,,,,,,,,
+Excessive  space,2019-07-29,,,,,,,,
+Miscellaenous ||whitespace | issues ,2019-07-29,,,,,,,,
+Duplicate||Duplicate,2019-07-29,,,,,,,,
+Invalid ISSN,2019-07-29,2321-2302,,,,,,,
+Invalid ISBN,2019-07-29,,978-0-306-40615-6,,,,,,
+Multiple valid ISSNs,2019-07-29,0378-5955||0024-9319,,,,,,,
+Multiple valid ISBNs,2019-07-29,,99921-58-10-7||978-0-306-40615-7,,,,,,
+Invalid date,2019-07-260,,,,,,,,
+Multiple dates,2019-07-26||2019-01-10,,,,,,,,
+Invalid multi-value separator,2019-07-29,0378-5955|0024-9319,,,,,,,
+Unnecessary Unicode,2019-07-29,,,,,,,,
+Suspicious character||foreˆt,2019-07-29,,,,,,,,
+Invalid ISO 639-1 (alpha 2) language,2019-07-29,,,jp,,,,,
+Invalid ISO 639-3 (alpha 3) language,2019-07-29,,,chi,,,,,
+Invalid language,2019-07-29,,,Span,,,,,
+Invalid AGROVOC subject,2019-07-29,,,,FOREST,,,,
 Newline (LF),2019-07-30,,,,"TANZA
-NIA",,
-Missing date,,,,,,,
-Invalid country,2019-08-01,,,,,KENYAA,
-Uncommon filename extension,2019-08-10,,,,,,file.pdf.lck
-Unneccesary unicode (U+002D + U+00AD),2019-08-10,,978-92-9043-823-6,,,,
-"Missing space,after comma",2019-08-27,,,,,,
+NIA",,,,
+Missing date,,,,,,,,,
+Invalid country,2019-08-01,,,,,KENYAA,,,
+Uncommon filename extension,2019-08-10,,,,,,file.pdf.lck,,
+Unneccesary unicode (U+002D + U+00AD),2019-08-10,,978-92-9043-823-6,,,,,,
+"Missing space,after comma",2019-08-27,,,,,,,,
+Incorrect ISO 639-1 language,2019-09-26,,,es,,,,,
+Incorrect ISO 639-3 language,2019-09-26,,,spa,,,,,
+Composéd Unicode,2020-01-14,,,,,,,,
+Decomposéd Unicode,2020-01-14,,,,,,,,
+Unnecessary multi-value separator,2021-01-03,0378-5955||,,,,,,,
+Invalid SPDX license identifier,2021-03-11,,,,,,,CC-BY,
+Duplicate Title,2021-03-17,,,,,,,,Report
+Duplicate Title,2021-03-17,,,,,,,,Report
+Mojibake,2021-03-18,,,,CIAT PublicaÃ§ao,,,,Report
--- a/poetry.lock
+++ b/poetry.lock
--- a/pyproject.toml
+++ b/pyproject.toml
@ -0,0 +1,37 @@
+[tool.poetry]
+name = "csv-metadata-quality"
+version = "0.4.8-dev"
+description="A simple, but opinionated CSV quality checking and fixing pipeline for CSVs in the DSpace ecosystem."
+authors = ["Alan Orth <alan.orth@gmail.com>"]
+license="GPL-3.0-only"
+repository = "https://github.com/ilri/csv-metadata-quality"
+homepage = "https://github.com/ilri/csv-metadata-quality"
+
+[tool.poetry.scripts]
+csv-metadata-quality = 'csv_metadata_quality.__main__:main'
+
+[tool.poetry.dependencies]
+python = "^3.7.1"
+pandas = "^1.0.4"
+python-stdnum = "^1.13"
+xlrd = "^1.2.0"
+requests = "^2.23.0"
+requests-cache = "~0.6.4"
+pycountry = "^19.8.18"
+langid = "^1.1.6"
+colorama = "^0.4.4"
+spdx-license-list = "^0.5.2"
+ftfy = "^5.9"
+
+[tool.poetry.dev-dependencies]
+pytest = "^6.1.1"
+ipython = { version = "^7.18.1", python = "^3.7" }
+flake8 = "^3.8.4"
+pytest-clarity = "^1.0.1"
+black = "^21.6b0"
+isort = "^5.5.4"
+csvkit = "^1.0.5"
+
+[build-system]
+requires = ["poetry>=0.12"]
+build-backend = "poetry.masonry.api"
--- a/pytest.ini
+++ b/pytest.ini
@ -1,5 +1,5 @@
 [pytest]
-addopts= -rsxX -s -v --strict --capture=sys
+addopts= -rsxX -s -v --strict-markers --capture=sys
 filterwarnings =
    error::UserWarning
    ignore:.*U.* is deprecated:DeprecationWarning
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@ -1,32 +1,81 @@
-i https://pypi.org/simple
-atomicwrites==1.3.0
-attrs==19.1.0
-backcall==0.1.0
-decorator==4.4.0
-entrypoints==0.3
-flake8==3.7.8
-importlib-metadata==0.19
-ipython-genutils==0.2.0
-ipython==7.7.0
-jedi==0.14.1
-mccabe==0.6.1
-more-itertools==7.2.0
-packaging==19.1
-parso==0.5.1
-pexpect==4.7.0 ; sys_platform != 'win32'
-pickleshare==0.7.5
-pluggy==0.12.0
-prompt-toolkit==2.0.9
-ptyprocess==0.6.0
-py==1.8.0
-pycodestyle==2.5.0
-pyflakes==2.1.1
-pygments==2.4.2
-pyparsing==2.4.2
-pytest-clarity==0.2.0a1
-pytest==5.0.1
-six==1.12.0
-termcolor==1.1.0
-traitlets==4.3.2
-wcwidth==0.1.7
-zipp==0.5.2
+agate-dbf==0.2.2
+agate-excel==0.2.3
+agate-sql==0.5.6
+agate==1.6.2
+appdirs==1.4.4; python_full_version >= "3.6.2"
+appnope==0.1.2; python_version >= "3.7" and python_version < "4.0" and sys_platform == "darwin"
+atomicwrites==1.4.0; python_version >= "3.6" and python_full_version < "3.0.0" and sys_platform == "win32" and (python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.4.0" and python_version >= "3.6") or sys_platform == "win32" and python_version >= "3.6" and python_full_version >= "3.4.0" and (python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.4.0" and python_version >= "3.6")
+attrs==21.2.0; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.5.0" and python_version >= "3.6"
+babel==2.9.1; python_version >= "2.7" and python_full_version < "3.0.0" or python_full_version >= "3.4.0"
+backcall==0.2.0; python_version >= "3.7" and python_version < "4.0"
+black==21.6b0; python_full_version >= "3.6.2"
+certifi==2021.5.30; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.5.0" and python_version >= "3.6"
+chardet==4.0.0; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.5.0" and python_version >= "3.6"
+click==8.0.1; python_version >= "3.6" and python_full_version >= "3.6.2"
+colorama==0.4.4; (python_version >= "2.7" and python_full_version < "3.0.0") or (python_full_version >= "3.5.0")
+commonmark==0.9.1; python_version >= "3.6" and python_version < "4.0" and (python_version >= "2.7" and python_full_version < "3.0.0" or python_full_version >= "3.4.0")
+csvkit==1.0.5
+dbfread==2.0.7
+decorator==5.0.9; python_version >= "3.7" and python_version < "4.0"
+et-xmlfile==1.1.0; python_version >= "3.6"
+flake8==3.9.2; (python_version >= "2.7" and python_full_version < "3.0.0") or (python_full_version >= "3.5.0")
+ftfy==5.9; python_version >= "3.5"
+greenlet==1.1.0; python_version >= "3" and python_full_version < "3.0.0" or python_full_version >= "3.6.0" and python_version >= "3"
+idna==2.10; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.5.0" and python_version >= "3.6"
+importlib-metadata==4.6.1; python_version < "3.8" and python_version >= "3.6" and (python_version >= "3.6" and python_full_version < "3.0.0" and python_version < "3.8" or python_full_version >= "3.5.0" and python_version < "3.8" and python_version >= "3.6") and (python_version >= "3.6" and python_full_version < "3.0.0" and python_version < "3.8" or python_full_version >= "3.4.0" and python_version >= "3.6" and python_version < "3.8") and (python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.4.0" and python_version >= "3.6") and python_full_version >= "3.6.2" and (python_version >= "3.6" and python_full_version < "3.0.0" and python_version < "3.8" or python_full_version >= "3.6.0" and python_version < "3.8" and python_version >= "3.6")
+iniconfig==1.1.1; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.4.0" and python_version >= "3.6"
+ipython-genutils==0.2.0; python_version >= "3.7" and python_version < "4.0"
+ipython==7.25.0; python_version >= "3.7" and python_version < "4.0"
+isodate==0.6.0
+isort==5.9.1; python_full_version >= "3.6.1" and python_version < "4.0"
+itsdangerous==2.0.1; python_version >= "3.6"
+jedi==0.18.0; python_version >= "3.7" and python_version < "4.0"
+langid==1.1.6
+leather==0.3.3
+matplotlib-inline==0.1.2; python_version >= "3.7" and python_version < "4.0"
+mccabe==0.6.1; python_version >= "2.7" and python_full_version < "3.0.0" or python_full_version >= "3.5.0"
+mypy-extensions==0.4.3; python_full_version >= "3.6.2"
+numpy==1.21.0; python_version >= "3.7" and python_full_version >= "3.7.1"
+openpyxl==3.0.7; python_version >= "3.6"
+packaging==21.0; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.4.0" and python_version >= "3.6"
+pandas==1.3.0; python_full_version >= "3.7.1"
+parsedatetime==2.6
+parso==0.8.2; python_version >= "3.7" and python_version < "4.0"
+pathspec==0.8.1; python_full_version >= "3.6.2"
+pexpect==4.8.0; python_version >= "3.7" and python_version < "4.0" and sys_platform != "win32"
+pickleshare==0.7.5; python_version >= "3.7" and python_version < "4.0"
+pluggy==0.13.1; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.4.0" and python_version >= "3.6"
+pprintpp==0.4.0; python_version >= "2.7" and python_full_version < "3.0.0" or python_full_version >= "3.4.0"
+prompt-toolkit==3.0.19; python_version >= "3.7" and python_version < "4.0" and python_full_version >= "3.6.1"
+ptyprocess==0.7.0; python_version >= "3.7" and python_version < "4.0" and sys_platform != "win32"
+py==1.10.0; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.4.0" and python_version >= "3.6"
+pycodestyle==2.7.0; python_version >= "2.7" and python_full_version < "3.0.0" or python_full_version >= "3.5.0"
+pycountry==19.8.18
+pyflakes==2.3.1; python_version >= "2.7" and python_full_version < "3.0.0" or python_full_version >= "3.5.0"
+pygments==2.9.0; python_version >= "3.7" and python_version < "4.0" and (python_version >= "2.7" and python_full_version < "3.0.0" or python_full_version >= "3.4.0")
+pyicu==2.7.4
+pyparsing==2.4.7; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.3.0" and python_version >= "3.6"
+pytest-clarity==1.0.1; (python_version >= "2.7" and python_full_version < "3.0.0") or (python_full_version >= "3.4.0")
+pytest==6.2.4; python_version >= "3.6"
+python-dateutil==2.8.1; python_full_version >= "3.7.1"
+python-slugify==5.0.2; python_version >= "3.6"
+python-stdnum==1.16
+pytimeparse==1.1.8
+pytz==2021.1; python_full_version >= "3.7.1"
+regex==2021.7.6; python_full_version >= "3.6.2"
+requests-cache==0.6.4; python_version >= "3.6"
+requests==2.25.1; (python_version >= "2.7" and python_full_version < "3.0.0") or (python_full_version >= "3.5.0")
+rich==10.5.0; python_version >= "3.6" and python_version < "4.0" and (python_version >= "2.7" and python_full_version < "3.0.0" or python_full_version >= "3.4.0")
+six==1.16.0; python_full_version >= "3.7.1" and python_version >= "3.6" and (python_version >= "2.7" and python_full_version < "3.0.0" or python_full_version >= "3.3.0")
+spdx-license-list==0.5.2
+sqlalchemy==1.4.20; python_version >= "2.7" and python_full_version < "3.0.0" or python_full_version >= "3.6.0"
+text-unidecode==1.3; python_version >= "3.6"
+toml==0.10.2; python_full_version >= "3.6.2" and python_version >= "3.6" and (python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.4.0" and python_version >= "3.6")
+traitlets==5.0.5; python_version >= "3.7" and python_version < "4.0"
+typed-ast==1.4.3; python_version < "3.8" and python_full_version >= "3.6.2"
+typing-extensions==3.10.0.0; python_version < "3.8" and python_full_version >= "3.6.2" and python_version >= "3.6" and (python_version >= "2.7" and python_full_version < "3.0.0" or python_full_version >= "3.4.0")
+url-normalize==1.4.3; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.6.0" and python_version >= "3.6"
+urllib3==1.26.6; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.5.0" and python_version < "4" and python_version >= "3.6"
+wcwidth==0.2.5; python_version >= "3.7" and python_version < "4.0" and python_full_version >= "3.6.1"
+xlrd==1.2.0; (python_version >= "2.7" and python_full_version < "3.0.0") or (python_full_version >= "3.4.0")
+zipp==3.5.0; python_version < "3.8" and python_version >= "3.6"
--- a/requirements.txt
+++ b/requirements.txt
@ -1,16 +1,21 @@
-i https://pypi.org/simple
-e .
-certifi==2019.6.16
-chardet==3.0.4
-idna==2.8
-numpy==1.17.0
-pandas==0.25.0
-pycountry==19.7.15
-python-dateutil==2.8.0
-python-stdnum==1.11
-pytz==2019.2
-requests-cache==0.5.0
-requests==2.22.0
-six==1.12.0
-urllib3==1.25.3
-xlrd==1.2.0
+certifi==2021.5.30; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.5.0" and python_version >= "3.6"
+chardet==4.0.0; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.5.0" and python_version >= "3.6"
+colorama==0.4.4; (python_version >= "2.7" and python_full_version < "3.0.0") or (python_full_version >= "3.5.0")
+ftfy==5.9; python_version >= "3.5"
+idna==2.10; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.5.0" and python_version >= "3.6"
+itsdangerous==2.0.1; python_version >= "3.6"
+langid==1.1.6
+numpy==1.21.0; python_version >= "3.7" and python_full_version >= "3.7.1"
+pandas==1.3.0; python_full_version >= "3.7.1"
+pycountry==19.8.18
+python-dateutil==2.8.1; python_full_version >= "3.7.1"
+python-stdnum==1.16
+pytz==2021.1; python_full_version >= "3.7.1"
+requests-cache==0.6.4; python_version >= "3.6"
+requests==2.25.1; (python_version >= "2.7" and python_full_version < "3.0.0") or (python_full_version >= "3.5.0")
+six==1.16.0; python_full_version >= "3.7.1" and python_version >= "3.6"
+spdx-license-list==0.5.2
+url-normalize==1.4.3; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.6.0" and python_version >= "3.6"
+urllib3==1.26.6; python_version >= "3.6" and python_full_version < "3.0.0" or python_full_version >= "3.5.0" and python_version < "4" and python_version >= "3.6"
+wcwidth==0.2.5; python_version >= "3.5"
+xlrd==1.2.0; (python_version >= "2.7" and python_full_version < "3.0.0") or (python_full_version >= "3.4.0")
--- a/setup.cfg
+++ b/setup.cfg
@ -0,0 +1,6 @@
+[isort]
+multi_line_output=3
+include_trailing_comma=True
+force_grid_wrap=0
+use_parentheses=True
+line_length=88
--- a/setup.py
+++ b/setup.py
@ -4,16 +4,17 @@ with open("README.md", "r") as fh:
    long_description = fh.read()

 install_requires = [
-    'pandas',
-    'python-stdnum',
-    'requests',
-    'requests-cache',
-    'pycountry'
+    "pandas",
+    "python-stdnum",
+    "requests",
+    "requests-cache",
+    "pycountry",
+    "langid",
 ]

 setuptools.setup(
    name="csv-metadata-quality",
-    version="0.2.2",
+    version="0.4.8-dev",
    author="Alan Orth",
    author_email="aorth@mjanja.ch",
    description="A simple, but opinionated CSV quality checking and fixing pipeline for CSVs in the DSpace ecosystem.",
@ -22,17 +23,15 @@ setuptools.setup(
    long_description_content_type="text/markdown",
    url="https://github.com/alanorth/csv-metadata-quality",
    classifiers=[
-        "Programming Language :: Python :: 3.6",
        "Programming Language :: Python :: 3.7",
+        "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
        "License :: OSI Approved :: GNU General Public License v3 (GPLv3)",
        "Operating System :: OS Independent",
-        "Development Status :: 4 - Beta"
    ],
-    packages=['csv_metadata_quality'],
+    packages=["csv_metadata_quality"],
    entry_points={
-        'console_scripts': [
-            'csv-metadata-quality = csv_metadata_quality.__main__:main'
-        ]
+        "console_scripts": ["csv-metadata-quality = csv_metadata_quality.__main__:main"]
    },
-    install_requires=install_requires
+    install_requires=install_requires,
 )
--- a/tests/test_check.py
+++ b/tests/test_check.py
@ -1,225 +1,369 @@
+# SPDX-License-Identifier: GPL-3.0-only
+
+import pandas as pd
+from colorama import Fore
+
 import csv_metadata_quality.check as check
+import csv_metadata_quality.experimental as experimental


 def test_check_invalid_issn(capsys):
-    '''Test checking invalid ISSN.'''
+    """Test checking invalid ISSN."""

-    value = '2321-2302'
+    value = "2321-2302"

    check.issn(value)

    captured = capsys.readouterr()
-    assert captured.out == f'Invalid ISSN: {value}\n'
+    assert captured.out == f"{Fore.RED}Invalid ISSN: {Fore.RESET}{value}\n"


 def test_check_valid_issn():
-    '''Test checking valid ISSN.'''
+    """Test checking valid ISSN."""

-    value = '0024-9319'
+    value = "0024-9319"

    result = check.issn(value)

-    assert result == value
+    assert result == None


 def test_check_invalid_isbn(capsys):
-    '''Test checking invalid ISBN.'''
+    """Test checking invalid ISBN."""

-    value = '99921-58-10-6'
+    value = "99921-58-10-6"

    check.isbn(value)

    captured = capsys.readouterr()
-    assert captured.out == f'Invalid ISBN: {value}\n'
+    assert captured.out == f"{Fore.RED}Invalid ISBN: {Fore.RESET}{value}\n"


 def test_check_valid_isbn():
-    '''Test checking valid ISBN.'''
+    """Test checking valid ISBN."""

-    value = '99921-58-10-7'
+    value = "99921-58-10-7"

    result = check.isbn(value)

-    assert result == value
-
-
-def test_check_invalid_separators(capsys):
-    '''Test checking invalid multi-value separators.'''
-
-    value = 'Alan|Orth'
-
-    check.separators(value)
-
-    captured = capsys.readouterr()
-    assert captured.out == f'Invalid multi-value separator: {value}\n'
-
-
-def test_check_valid_separators():
-    '''Test checking valid multi-value separators.'''
-
-    value = 'Alan||Orth'
-
-    result = check.separators(value)
-
-    assert result == value
+    assert result == None


 def test_check_missing_date(capsys):
-    '''Test checking missing date.'''
+    """Test checking missing date."""

    value = None

-    field_name = 'dc.date.issued'
+    field_name = "dc.date.issued"

    check.date(value, field_name)

    captured = capsys.readouterr()
-    assert captured.out == f'Missing date ({field_name}).\n'
+    assert captured.out == f"{Fore.RED}Missing date ({field_name}).{Fore.RESET}\n"


 def test_check_multiple_dates(capsys):
-    '''Test checking multiple dates.'''
+    """Test checking multiple dates."""

-    value = '1990||1991'
+    value = "1990||1991"

-    field_name = 'dc.date.issued'
+    field_name = "dc.date.issued"

    check.date(value, field_name)

    captured = capsys.readouterr()
-    assert captured.out == f'Multiple dates not allowed ({field_name}): {value}\n'
+    assert (
+        captured.out
+        == f"{Fore.RED}Multiple dates not allowed ({field_name}): {Fore.RESET}{value}\n"
+    )


 def test_check_invalid_date(capsys):
-    '''Test checking invalid ISO8601 date.'''
+    """Test checking invalid ISO8601 date."""

-    value = '1990-0'
+    value = "1990-0"

-    field_name = 'dc.date.issued'
+    field_name = "dc.date.issued"

    check.date(value, field_name)

    captured = capsys.readouterr()
-    assert captured.out == f'Invalid date ({field_name}): {value}\n'
+    assert (
+        captured.out == f"{Fore.RED}Invalid date ({field_name}): {Fore.RESET}{value}\n"
+    )


 def test_check_valid_date():
-    '''Test checking valid ISO8601 date.'''
+    """Test checking valid ISO8601 date."""

-    value = '1990'
+    value = "1990"

-    field_name = 'dc.date.issued'
+    field_name = "dc.date.issued"

    result = check.date(value, field_name)

-    assert result == value
+    assert result == None


 def test_check_suspicious_characters(capsys):
-    '''Test checking for suspicious characters.'''
+    """Test checking for suspicious characters."""

-    value = 'foreˆt'
+    value = "foreˆt"

-    field_name = 'dc.contributor.author'
+    field_name = "dc.contributor.author"

    check.suspicious_characters(value, field_name)

    captured = capsys.readouterr()
-    assert captured.out == f'Suspicious character ({field_name}): ˆt\n'
+    assert (
+        captured.out
+        == f"{Fore.YELLOW}Suspicious character ({field_name}): {Fore.RESET}ˆt\n"
+    )


-def test_check_valid_iso639_2_language():
-    '''Test valid ISO 639-2 language.'''
+def test_check_valid_iso639_1_language():
+    """Test valid ISO 639-1 (alpha 2) language."""

-    value = 'ja'
+    value = "ja"

    result = check.language(value)

-    assert result == value
+    assert result == None


 def test_check_valid_iso639_3_language():
-    '''Test invalid ISO 639-3 language.'''
+    """Test valid ISO 639-3 (alpha 3) language."""

-    value = 'eng'
+    value = "eng"

    result = check.language(value)

-    assert result == value
+    assert result == None


-def test_check_invalid_iso639_2_language(capsys):
-    '''Test invalid ISO 639-2 language.'''
+def test_check_invalid_iso639_1_language(capsys):
+    """Test invalid ISO 639-1 (alpha 2) language."""

-    value = 'jp'
+    value = "jp"

    check.language(value)

    captured = capsys.readouterr()
-    assert captured.out == f'Invalid ISO 639-2 language: {value}\n'
+    assert (
+        captured.out == f"{Fore.RED}Invalid ISO 639-1 language: {Fore.RESET}{value}\n"
+    )


 def test_check_invalid_iso639_3_language(capsys):
-    '''Test invalid ISO 639-3 language.'''
+    """Test invalid ISO 639-3 (alpha 3) language."""

-    value = 'chi'
+    value = "chi"

    check.language(value)

    captured = capsys.readouterr()
-    assert captured.out == f'Invalid ISO 639-3 language: {value}\n'
+    assert (
+        captured.out == f"{Fore.RED}Invalid ISO 639-3 language: {Fore.RESET}{value}\n"
+    )


 def test_check_invalid_language(capsys):
-    '''Test invalid language.'''
+    """Test invalid language."""

-    value = 'Span'
+    value = "Span"

    check.language(value)

    captured = capsys.readouterr()
-    assert captured.out == f'Invalid language: {value}\n'
+    assert captured.out == f"{Fore.RED}Invalid language: {Fore.RESET}{value}\n"


 def test_check_invalid_agrovoc(capsys):
-    '''Test invalid AGROVOC subject.'''
+    """Test invalid AGROVOC subject."""

-    value = 'FOREST'
-    field_name = 'dc.subject'
+    value = "FOREST"
+    field_name = "dcterms.subject"

    check.agrovoc(value, field_name)

    captured = capsys.readouterr()
-    assert captured.out == f'Invalid AGROVOC ({field_name}): {value}\n'
+    assert (
+        captured.out
+        == f"{Fore.RED}Invalid AGROVOC ({field_name}): {Fore.RESET}{value}\n"
+    )


 def test_check_valid_agrovoc():
-    '''Test valid AGROVOC subject.'''
+    """Test valid AGROVOC subject."""

-    value = 'FORESTS'
-    field_name = 'dc.subject'
+    value = "FORESTS"
+    field_name = "dcterms.subject"

    result = check.agrovoc(value, field_name)

-    assert result == value
+    assert result == None


 def test_check_uncommon_filename_extension(capsys):
-    '''Test uncommon filename extension.'''
+    """Test uncommon filename extension."""

-    value = 'file.pdf.lck'
+    value = "file.pdf.lck"

    check.filename_extension(value)

    captured = capsys.readouterr()
-    assert captured.out == f'Filename with uncommon extension: {value}\n'
+    assert (
+        captured.out
+        == f"{Fore.YELLOW}Filename with uncommon extension: {Fore.RESET}{value}\n"
+    )


 def test_check_common_filename_extension():
-    '''Test common filename extension.'''
+    """Test common filename extension."""

-    value = 'file.pdf'
+    value = "file.pdf"

    result = check.filename_extension(value)

-    assert result == value
+    assert result == None
+
+
+def test_check_incorrect_iso_639_1_language(capsys):
+    """Test incorrect ISO 639-1 language, as determined by comparing the item's language field with the actual language predicted in the item's title."""
+
+    title = "A randomised vaccine field trial in Kenya demonstrates protection against wildebeest-associated malignant catarrhal fever in cattle"
+    language = "es"
+
+    # Create a dictionary to mimic Pandas series
+    row = {"dc.title": title, "dc.language.iso": language}
+    series = pd.Series(row)
+
+    experimental.correct_language(series)
+
+    captured = capsys.readouterr()
+    assert (
+        captured.out
+        == f"{Fore.YELLOW}Possibly incorrect language {language} (detected en): {Fore.RESET}{title}\n"
+    )
+
+
+def test_check_incorrect_iso_639_3_language(capsys):
+    """Test incorrect ISO 639-3 language, as determined by comparing the item's language field with the actual language predicted in the item's title."""
+
+    title = "A randomised vaccine field trial in Kenya demonstrates protection against wildebeest-associated malignant catarrhal fever in cattle"
+    language = "spa"
+
+    # Create a dictionary to mimic Pandas series
+    row = {"dc.title": title, "dc.language.iso": language}
+    series = pd.Series(row)
+
+    experimental.correct_language(series)
+
+    captured = capsys.readouterr()
+    assert (
+        captured.out
+        == f"{Fore.YELLOW}Possibly incorrect language {language} (detected eng): {Fore.RESET}{title}\n"
+    )
+
+
+def test_check_correct_iso_639_1_language():
+    """Test correct ISO 639-1 language, as determined by comparing the item's language field with the actual language predicted in the item's title."""
+
+    title = "A randomised vaccine field trial in Kenya demonstrates protection against wildebeest-associated malignant catarrhal fever in cattle"
+    language = "en"
+
+    # Create a dictionary to mimic Pandas series
+    row = {"dc.title": title, "dc.language.iso": language}
+    series = pd.Series(row)
+
+    result = experimental.correct_language(series)
+
+    assert result == None
+
+
+def test_check_correct_iso_639_3_language():
+    """Test correct ISO 639-3 language, as determined by comparing the item's language field with the actual language predicted in the item's title."""
+
+    title = "A randomised vaccine field trial in Kenya demonstrates protection against wildebeest-associated malignant catarrhal fever in cattle"
+    language = "eng"
+
+    # Create a dictionary to mimic Pandas series
+    row = {"dc.title": title, "dc.language.iso": language}
+    series = pd.Series(row)
+
+    result = experimental.correct_language(series)
+
+    assert result == None
+
+
+def test_check_valid_spdx_license_identifier():
+    """Test valid SPDX license identifier."""
+
+    license = "CC-BY-SA-4.0"
+
+    result = check.spdx_license_identifier(license)
+
+    assert result == None
+
+
+def test_check_invalid_spdx_license_identifier(capsys):
+    """Test invalid SPDX license identifier."""
+
+    license = "CC-BY-SA"
+
+    result = check.spdx_license_identifier(license)
+
+    captured = capsys.readouterr()
+    assert (
+        captured.out
+        == f"{Fore.YELLOW}Non-SPDX license identifier: {Fore.RESET}{license}\n"
+    )
+
+
+def test_check_duplicate_item(capsys):
+    """Test item with duplicate title, type, and date."""
+
+    item_title = "Title"
+    item_type = "Report"
+    item_date = "2021-03-17"
+
+    d = {
+        "dc.title": [item_title, item_title],
+        "dcterms.type": [item_type, item_type],
+        "dcterms.issued": [item_date, item_date],
+    }
+    df = pd.DataFrame(data=d)
+
+    result = check.duplicate_items(df)
+
+    captured = capsys.readouterr()
+    assert (
+        captured.out
+        == f"{Fore.YELLOW}Possible duplicate (dc.title): {Fore.RESET}{item_title}\n"
+    )
+
+
+def test_check_no_mojibake():
+    """Test string with no mojibake."""
+
+    field = "CIAT Publicaçao"
+    field_name = "dcterms.isPartOf"
+
+    result = check.mojibake(field, field_name)
+
+    assert result == None
+
+
+def test_check_mojibake(capsys):
+    """Test string with mojibake."""
+
+    field = "CIAT PublicaÃ§ao"
+    field_name = "dcterms.isPartOf"
+
+    result = check.mojibake(field, field_name)
+
+    captured = capsys.readouterr()
+    assert (
+        captured.out
+        == f"{Fore.YELLOW}Possible encoding issue ({field_name}): {Fore.RESET}{field}\n"
+    )
--- a/tests/test_fix.py
+++ b/tests/test_fix.py
@ -1,68 +1,121 @@
+# SPDX-License-Identifier: GPL-3.0-only
+
 import csv_metadata_quality.fix as fix


 def test_fix_leading_whitespace():
-    '''Test fixing leading whitespace.'''
+    """Test fixing leading whitespace."""

-    value = ' Alan'
+    value = " Alan"

-    assert fix.whitespace(value) == 'Alan'
+    field_name = "dc.contributor.author"
+
+    assert fix.whitespace(value, field_name) == "Alan"


 def test_fix_trailing_whitespace():
-    '''Test fixing trailing whitespace.'''
+    """Test fixing trailing whitespace."""

-    value = 'Alan '
+    value = "Alan "

-    assert fix.whitespace(value) == 'Alan'
+    field_name = "dc.contributor.author"
+
+    assert fix.whitespace(value, field_name) == "Alan"


 def test_fix_excessive_whitespace():
-    '''Test fixing excessive whitespace.'''
+    """Test fixing excessive whitespace."""

-    value = 'Alan  Orth'
+    value = "Alan  Orth"

-    assert fix.whitespace(value) == 'Alan Orth'
+    field_name = "dc.contributor.author"
+
+    assert fix.whitespace(value, field_name) == "Alan Orth"


 def test_fix_invalid_separators():
-    '''Test fixing invalid multi-value separators.'''
+    """Test fixing invalid multi-value separators."""

-    value = 'Alan|Orth'
+    value = "Alan|Orth"

-    assert fix.separators(value) == 'Alan||Orth'
+    field_name = "dc.contributor.author"
+
+    assert fix.separators(value, field_name) == "Alan||Orth"
+
+
+def test_fix_unnecessary_separators():
+    """Test fixing unnecessary multi-value separators."""
+
+    field = "Alan||Orth||"
+
+    field_name = "dc.contributor.author"
+
+    assert fix.separators(field, field_name) == "Alan||Orth"


 def test_fix_unnecessary_unicode():
-    '''Test fixing unnecessary Unicode.'''
+    """Test fixing unnecessary Unicode."""

-    value = 'Alan Orth'
+    value = "Alan Orth"

-    assert fix.unnecessary_unicode(value) == 'Alan Orth'
+    assert fix.unnecessary_unicode(value) == "Alan Orth"


 def test_fix_duplicates():
-    '''Test fixing duplicate metadata values.'''
+    """Test fixing duplicate metadata values."""

-    value = 'Kenya||Kenya'
+    value = "Kenya||Kenya"

-    assert fix.duplicates(value) == 'Kenya'
+    field_name = "dc.contributor.author"
+
+    assert fix.duplicates(value, field_name) == "Kenya"


 def test_fix_newlines():
-    '''Test fixing newlines.'''
+    """Test fixing newlines."""

-    value = '''Ken
-ya'''
+    value = """Ken
+ya"""

-    assert fix.newlines(value) == 'Kenya'
+    assert fix.newlines(value) == "Kenya"


 def test_fix_comma_space():
-    '''Test adding space after comma.'''
+    """Test adding space after comma."""

-    value = 'Orth,Alan S.'
+    value = "Orth,Alan S."

-    field_name = 'dc.contributor.author'
+    field_name = "dc.contributor.author"

-    assert fix.comma_space(value, field_name) == 'Orth, Alan S.'
+    assert fix.comma_space(value, field_name) == "Orth, Alan S."
+
+
+def test_fix_normalized_unicode():
+    """Test fixing a string that is already in its normalized (NFC) Unicode form."""
+
+    # string using the normalized canonical form of é
+    value = "Ouédraogo, Mathieu"
+
+    field_name = "dc.contributor.author"
+
+    assert fix.normalize_unicode(value, field_name) == "Ouédraogo, Mathieu"
+
+
+def test_fix_decomposed_unicode():
+    """Test fixing a string that contains Unicode string."""
+
+    # string using the decomposed form of é
+    value = "Ouédraogo, Mathieu"
+
+    field_name = "dc.contributor.author"
+
+    assert fix.normalize_unicode(value, field_name) == "Ouédraogo, Mathieu"
+
+
+def test_fix_mojibake():
+    """Test string with no mojibake."""
+
+    field = "CIAT PublicaÃ§ao"
+    field_name = "dcterms.isPartOf"
+
+    assert fix.mojibake(field, field_name) == "CIAT Publicaçao"