blackifying tests

docs/contributing.rst

@@ -114,6 +114,7 @@ Steps to develop the theme
 2. Install theme dependencies
 3. Run development server
 4. Build production assets
+5. Install the testing infrastructure
 
 .. Attention::
 
@@ -189,6 +190,28 @@ run:
     yarn build:production
 
 
+Install the test infrastructure
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+This theme uses ``pytest`` for its testing, with a lightweight fixture defined
+in the ``test_build.py`` script that makes it easy to run a Sphinx build using
+this theme and inspect the results.
+
+In addition, we use `pytest-regressions <https://pytest-regressions.readthedocs.io/en/latest/>`_
+to ensure that the HTML generated by the theme is what we'd expect. This module
+provides a ``file_regression`` fixture that will check the contents of an object
+against a reference file on disk. If the structure of the two differs, then the
+test will fail. If we *expect* the structure to differ, then delete the file on
+disk and run the test. A new file will be created, and subsequent tests will pass.
+
+Install the testing dependencies with:
+
+.. code-block:: bash
+
+   pip install pytest pytest-regressions
+
+Then run the tests by calling ``pytest`` from the repository root.
+
 Changing fonts
 --------------
 

tests/sites/base/conf.py

@@ -17,5 +17,4 @@
 html_sourcelink_suffix = ""
 
 # Base options, we can add other key/vals later
-html_theme_options = {
-}
+html_theme_options = {}

tests/test_build.py

@@ -63,6 +63,8 @@ def test_build_book(file_regression, sphinx_build):
 
     # Sidebar subpage
     sidebar = subpage_html.select(".bd-sidebar")[0]
-    file_regression.check(sidebar.prettify(), basename="sidebar_subpage", extension=".html")
+    file_regression.check(
+        sidebar.prettify(), basename="sidebar_subpage", extension=".html"
+    )
 
     sphinx_build.clean()