Django Template Coverage.py Plugin

A coverage.py plugin to measure test coverage of Django templates.

Supported on:

Python: 3.8 through 3.12.
Django: 2.x, 3.x and 4.x.
Coverage.py: 6.x or higher.

The plugin is pip installable:

$ python3 -m pip install django_coverage_plugin

To run it, add this setting to your .coveragerc file:

[run]
plugins = django_coverage_plugin

Then run your tests under coverage.py.

You will see your templates listed in your coverage report along with your Python modules. Please use coverage.py v4.4 or greater to allow the plugin to identify untested templates.

If you get a django.core.exceptions.ImproperlyConfigured error, you need to set the DJANGO_SETTINGS_MODULE environment variable.

Template coverage only works if your Django templates have debugging enabled. If you get django_coverage_plugin.plugin.DjangoTemplatePluginException: Template debugging must be enabled in settings, or if no templates get measured, make sure you have TEMPLATES.OPTIONS.debug set to True in your settings file:

TEMPLATES = [
    {
        ...
        'OPTIONS': {
            'debug': True,
        },
    },
]

Configuration

The Django template plugin uses some existing settings from your .coveragerc file. The source=, include=, and omit= options control what template files are included in the report.

The plugin can find unused template and include them in your results. By default, it will look for files in your templates directory with an extension of .html, .htm, or .txt. You can configure it to look for a different set of extensions if you like:

[run]
plugins = django_coverage_plugin

[django_coverage_plugin]
template_extensions = html, txt, tex, email

If you use pyproject.toml for tool configuration use:

[tool.coverage.run]
plugins = [
    'django_coverage_plugin',
]

[tool.coverage.django_coverage_plugin]
template_extensions = 'html, txt, tex, email'

Caveats

Coverage.py can't tell whether a {% blocktrans %} tag used the singular or plural text, so both are marked as used if the tag is used.

What the? How?

The technique used to measure the coverage is the same that Dmitry Trofimov used in dtcov, but integrated into coverage.py as a plugin, and made more performant. I'd love to see how well it works in a real production project. If you want to help me with it, feel free to drop me an email.

The coverage.py plugin mechanism is designed to be generally useful for hooking into the collection and reporting phases of coverage.py, specifically to support non-Python files. If you have non-Python files you'd like to support in coverage.py, let's talk.

Tests

To run the tests:

$ python3 -m pip install -r requirements.txt
$ tox

History

v3.1.0 — 2023-07-10

Dropped support for Python 3.7 and Django 1.x. Declared support for Python 3.12.

v3.0.0 — 2022-12-06

Dropped support for Python 2.7, Python 3.6, and Django 1.8.

v2.0.4 — 2022-10-31

Declare our support for Python 3.11 and Django 4.1.

v2.0.3 — 2022-05-04

Add support for Django 4.0.

v2.0.2 — 2021-11-11

If a non-UTF8 file was found when looking for templates, it would fail when reading during the reporting phase, ending execution. This failure is now raised in a way that can be ignored with a .coveragerc setting of [report] ignore_errors=True (issue 78).

When using source=., an existing coverage HTML report directory would be found and believed to be unmeasured HTML template files. This is now fixed.

v2.0.1 — 2021-10-06

Test and claim our support on Python 3.10.

v2.0.0 — 2021-06-08

Drop support for Python 3.4 and 3.5.

A setting is available: template_extensions lets you set the file extensions that will be considered when looking for unused templates (requested in issue 60).

Fix an issue on Windows where file names were being compared case-sensitively, causing templates to be missed (issue 46).

Fix an issue (issue 63) where tag libraries can't be found if imported during test collection. Thanks to Daniel Izquierdo for the fix.

v1.8.0 — 2020-01-23

Add support for:

Coverage 5

v1.7.0 — 2020-01-16

Add support for:

Python 3.7 & 3.8
Django 2.2 & 3.0

v1.6.0 — 2018-09-04

Add support for Django 2.1.

v1.5.2 — 2017-10-18

Validates support for Django version 2.0b1. Improves discovery of template files.

v1.5.1a — 2017-04-05

Validates support for Django version 1.11. Testing for new package maintainer Pamela McA'Nulty

v1.5.0 — 2017-02-23

Removes support for Django versions below 1.8. Validates support for Django version 1.11b1

v1.4.2 — 2017-02-06

Fixes another instance of issue 32, which was the result of an initialization order problem.

v1.4.1 — 2017-01-25

Fixes issue 32, which was the result of an initialization order problem.

v1.4 — 2017-01-16

Django 1.10.5 is now supported.

Checking settings configuration is deferred so that settings.py is included in coverage reporting. Fixes issue 28.

Only the django.template.backends.django.DjangoTemplates template engine is supported, and it must be configured with ['OPTIONS']['debug'] = True. Fixes issue 27.

v1.3.1 — 2016-06-02

Settings are read slightly differently, so as to not interfere with programs that don't need settings. Fixes issue 18.

v1.3 — 2016-04-03

Multiple template engines are allowed. Thanks, Simon Charette.

v1.2.2 — 2016-02-01

No change in code, but Django 1.9.2 is now supported.

v1.2.1 — 2016-01-28

The template debug settings are checked properly for people still using TEMPLATE_DEBUG in newer versions of Django.

v1.2 — 2016-01-16

Check if template debugging is enabled in the settings, and raise a visible warning if not. This prevents mysterious failures of the plugin, and fixes issue 17.

Potential Django 1.9 support is included, but the patch to Django hasn't been applied yet.

v1.1 — 2015-11-12

Explicitly configure settings if need be to get things to work.

v1.0 — 2015-09-20

First version :)

nedbat/django_coverage_plugin

nedbat

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