Ensure dependencies are installed when building docs

.github/workflows/test.yml

@@ -99,7 +99,6 @@ jobs:
     - name: Docs
       if: startsWith(matrix.os, 'ubuntu') && matrix.python-version == 3.10
       run: |
-        python3 -m pip install furo sphinx-copybutton sphinx-issues sphinx-removed-in sphinxext-opengraph
         make doccheck
 
     - name: After success

Makefile

@@ -17,11 +17,12 @@ coverage:
 
 .PHONY: doc
 doc:
+	python3 -c "import PIL" > /dev/null 2>&1 || python3 -m pip install .
 	$(MAKE) -C docs html
 
 .PHONY: doccheck
 doccheck:
-	$(MAKE) -C docs html
+	$(MAKE) doc
 # Don't make our tests rely on the links in the docs being up every single build.
 # We don't control them.  But do check, and update them to the target of their redirects.
 	$(MAKE) -C docs linkcheck || true

docs/Makefile

@@ -43,8 +43,7 @@ clean:
 	-rm -rf $(BUILDDIR)/*
 
 install-sphinx:
-	$(PYTHON) -c "import sphinx" > /dev/null 2>&1 || $(PYTHON) -m pip install sphinx
-	$(PYTHON) -c "import furo" > /dev/null 2>&1 || $(PYTHON) -m pip install furo
+	$(PYTHON) -m pip install --quiet sphinx sphinx-copybutton sphinx-issues sphinx-removed-in sphinxext-opengraph furo olefile
 
 html:
 	$(MAKE) install-sphinx