Add a flag that saves the coverage output dir

This commit adds a pytest command line option `--no-cleanup` for
the coverage test. Running the coverage test with this option will
let users save the `kcov_output` directory so that it is easier to
inspect the coverage report.

Signed-off-by: Henry Wang <henry.wang@arm.com>

integration_tests/conftest.py

@@ -17,6 +17,13 @@ def pytest_addoption(parser):
             PROFILE_DEVEL
         )
     )
+    parser.addoption(
+        "--no-cleanup",
+        action="store_true",
+        default=False,
+        help="Keep the coverage report in `kcov_output` directory. If this flag is not provided, "
+             "both coverage related directories are removed."
+    )
 
 
 @pytest.fixture
@@ -24,6 +31,11 @@ def profile(request):
     return request.config.getoption("--profile")
 
 
+@pytest.fixture
+def no_cleanup(request):
+    return request.config.getoption("--no-cleanup")
+
+
 # This is used for defining global variables in pytest.
 def pytest_configure():
     pytest.profile_ci = PROFILE_CI

integration_tests/test_coverage.py

@@ -37,7 +37,7 @@ def _write_coverage_config(coverage_config):
         json.dump(coverage_config, outfile)
 
 
-def _get_current_coverage(coverage_config):
+def _get_current_coverage(coverage_config, no_cleanup):
     """Helper function that returns the coverage computed with kcov."""
     kcov_output_dir = os.path.join(REPO_ROOT_PATH, "kcov_output")
 
@@ -92,15 +92,17 @@ def _get_current_coverage(coverage_config):
         )[0])
 
     # Remove coverage related directories.
-    shutil.rmtree(kcov_output_dir, ignore_errors=True)
+    # If user provided `--no-cleanup` flag, `kcov_output_dir` should not be removed.
+    if not no_cleanup:
+        shutil.rmtree(kcov_output_dir, ignore_errors=True)
     shutil.rmtree(kcov_build_dir, ignore_errors=True)
 
     return coverage
 
 
-def test_coverage(profile):
+def test_coverage(profile, no_cleanup):
     coverage_config = _read_test_config()
-    current_coverage = _get_current_coverage(coverage_config)
+    current_coverage = _get_current_coverage(coverage_config, no_cleanup)
     previous_coverage = coverage_config["coverage_score"]
     if previous_coverage < current_coverage:
         if profile == pytest.profile_ci: