coverage: ensure that "coverage clean" does its job (#872)

- removed parameters from "coverage run" as they should be read from
the .coveragerc file.
- moved the contents of .coveragerc file to tox.ini and removed the
.coveragerc file.
- "coverage clean" now can see "coverage run" is being executed in
parallel mode and can now clean the artifacts properly.
- tox:testenv:coverage now runs "coverage clean" after the coverage report
generation.
- "coverage" will now generate coverage data to tox temp directory instead
of the project root.

misc:
- moved all tool configs to the upper part of the tox.ini file.
- renamed "coverage" to "coveragereport" to better reflect the what the
environment does.

Supersedes #871

Signed-off-by: Mustafa Kemal Gilor <[email protected]>

.github/workflows/tests.yaml

@@ -31,7 +31,7 @@ jobs:
         python -m pip install --upgrade pip
         pip install -r gh-test-requirements.txt
     - name: Test with tox
-      run: tox -e py3
+      run: tox -e py3-coverage
     - name: Test with tox (non-utc timezone)
       run: tox -e py3-non-utc-tz
     - name: Run pylint
@@ -40,8 +40,8 @@ jobs:
     - name: Run pep8
       run: tox -e pep8
       if: matrix.python-version == '3.10'
-    - name: Run coverage
-      run: tox -e coverage
+    - name: Run coveragereport
+      run: tox -e coveragereport
       if: matrix.python-version == '3.10'
     - name: Run bashate
       run: tox -e bashate

tox.ini

@@ -1,9 +1,33 @@
 [tox]
 skipsdist = True
-envlist = py3,coverage,pep8,pylint,bashate,yamllint,functional,hotyvalidate
+envlist = py3-coverage,coveragereport,pep8,pylint,bashate,yamllint,functional,hotyvalidate
 sitepackages = False
 minversion = 3.18.0
 
+# Tool configuration
+[flake8]
+# H106: Don't put vim configuration in source files
+# H203: Use assertIs(Not)None to check for None
+# H204: Use assert(Not)Equal to check for equality
+# H205: Use assert(Greater|Less)(Equal) for comparison
+# H904: Delay string interpolations at logging calls
+enable-extensions = H106,H203,H204,H205,H904
+show-source = true
+exclude = ./.*,build,dist,tests/unit/fake_data_root
+import-order-style = pep8
+
+[coverage:run]
+parallel = True
+branch = True
+source = hotsos
+omit = tests/*
+
+[coverage:report]
+ignore_errors = True
+skip_empty = True
+precision = 2
+fail_under = 84
+
 [testenv]
 basepython = {env:TOX_PYTHON:python3}
 unit_tests = {toxinidir}/tests/unit/
@@ -17,29 +41,27 @@ setenv =
     PYTHONHASHSEED=0
     TESTS_DIR={[testenv]unit_tests}
     non-utc-tz: TZ=EST+5
-    PYTHON=coverage run --source hotsos --parallel-mode
+    # Override the default coverage output path to tox's temp directory
+    # so we don't pollute the root dir.
+    COVERAGE_FILE={temp_dir}/.coverage
+    # Override the default "PYTHON" when the "-coverage" is present.
+    # This allows us to run additional steps on top of the default
+    # test run, such as changing the default interpreter to "coverage run".
+    coverage: PYTHON=coverage run
 deps =
     -r{toxinidir}/requirements.txt
     -r{toxinidir}/test-requirements.txt
 commands =
-    coverage erase
+    coverage: coverage erase
+    # This environment can "optionally" gather coverage data with "-coverage"
+    # suffix. The gathered coverage data is consumed by the "coverage" environment
+    # which merges the data and then generates coverage reports in HTML and XML
+    # formats.
     stestr run --random --slowest --test-path {[testenv]unit_tests} {posargs}
-
 [testenv:pep8]
 allowlist_externals = flake8
 commands = flake8 -v --exclude=fake_data_root {posargs:{[testenv]pyfiles}}
 
-[flake8]
-# H106: Don't put vim configuration in source files
-# H203: Use assertIs(Not)None to check for None
-# H204: Use assert(Not)Equal to check for equality
-# H205: Use assert(Greater|Less)(Equal) for comparison
-# H904: Delay string interpolations at logging calls
-enable-extensions = H106,H203,H204,H205,H904
-show-source = true
-exclude = ./.*,build,dist,tests/unit/fake_data_root
-import-order-style = pep8
-
 [testenv:pylint]
 allowlist_externals = pylint
 commands = pylint -v --rcfile={toxinidir}/pylintrc {posargs:{[testenv]pyfiles}}
@@ -59,13 +81,19 @@ commands = bash {toxinidir}/tools/test/functest.sh
 [testenv:docs]
 commands = sphinx-build -j auto -d {toxinidir}/doc/build/doctrees -b html {toxinidir}/doc/source doc/build/html
 
-[testenv:coverage]
-depends = py3
+[testenv:coveragereport]
+depends = py3-coverage
+description = 
+    'Generate code coverage reports from collected coverage information.
+    This environment depends on `py3-coverage` for generating the actual
+    code coverage data from the test run. To collect and generate in a
+    single step, run `tox -e py3-coverage,coveragereport`.'
 commands =
     coverage combine
     coverage report
     coverage html -d cover
     coverage xml -o cover/coverage.xml
+    coverage erase
 
 [testenv:hotyvalidate]
 setenv = PYTHONPATH={toxinidir}