tests: Add coverage testing

This commit adds coverage testing to the existing test suite.
Additionally it provides a separate `test_with_report` nox entry that
can be used to generate html reports in the internal CI.

Internal-tag: [#52078]
Signed-off-by: Robert Winkler <rwinkler@antmicro.com>

.ci.yml

@@ -25,7 +25,10 @@ pytest:
     - python3 -m pip install -r requirements.dev.txt
     - python3 -m pip install git+https://github.com/antmicro/tuttest
     - tuttest README.md | bash -
-    - nox -s tests
+    - nox -s tests_with_report
+  artifacts:
+    paths:
+      - cov_html
 
 docs-verify:
   stage: test
@@ -43,6 +46,7 @@ docs-build:
     - echo -en "\nhtml_js_files = [ '$ANNOTANT' ]" >> source/conf.py
     - make html latexpdf
     - cp build/latex/*.pdf build/html/
+    - cp -r ../cov_html build/html/cov
     - tar cf ../$CI_DOCS_ARCHIVE -C build/html/ .
   artifacts:
     paths:

noxfile.py

@@ -49,5 +49,10 @@ def black_check(session):
 @nox.session
 def tests(session: nox.Session) -> None:
     session.install("-r", "requirements.txt")
-    session.install("-r", "requirements.dev.txt")
-    session.run("pytest", "tests")
+    session.run("pytest", "--cov=fpga_topwrap", "tests")
+
+
+@nox.session
+def tests_with_report(session: nox.Session) -> None:
+    session.install("-r", "requirements.txt")
+    session.run("pytest", "--cov-report", "html:cov_html", "--cov=fpga_topwrap", "tests")

requirements.dev.txt

@@ -2,4 +2,5 @@ flake8
 nox
 pre-commit
 pytest
+pytest-cov
 pytest-lazy-fixtures