fix(tests): enhance pytest-cov detection (#25683)

fixes #25590

Author: eleanorjboyd

python_files/tests/pytestadapter/helpers.py

@@ -264,17 +264,34 @@ def runner_with_cwd_env(
         pipe_name = generate_random_pipe_name("pytest-discovery-test")
 
     if "COVERAGE_ENABLED" in env_add and "_TEST_VAR_UNITTEST" not in env_add:
-        process_args = [
-            sys.executable,
-            "-m",
-            "pytest",
-            "-p",
-            "vscode_pytest",
-            "--cov=.",
-            "--cov-branch",
-            "-s",
-            *args,
-        ]
+        if "_PYTEST_MANUAL_PLUGIN_LOAD" in env_add:
+            # Test manual plugin loading scenario for issue #25590
+            process_args = [
+                sys.executable,
+                "-m",
+                "pytest",
+                "--disable-plugin-autoload",
+                "-p",
+                "pytest_cov.plugin",
+                "-p",
+                "vscode_pytest",
+                "--cov=.",
+                "--cov-branch",
+                "-s",
+                *args,
+            ]
+        else:
+            process_args = [
+                sys.executable,
+                "-m",
+                "pytest",
+                "-p",
+                "vscode_pytest",
+                "--cov=.",
+                "--cov-branch",
+                "-s",
+                *args,
+            ]
 
     # Generate pipe name, pipe name specific per OS type.
 

python_files/tests/pytestadapter/test_coverage.py

@@ -142,3 +142,23 @@ def test_coverage_w_omit_config():
     assert results
     # assert one file is reported and one file (as specified in pyproject.toml) is omitted
     assert len(results) == 1
+
+
+def test_pytest_cov_manual_plugin_loading():
+    """
+    Test that pytest-cov is detected when loaded manually via -p pytest_cov.plugin.
+
+    This test verifies the fix for issue #25590, where pytest-cov detection failed
+    when using --disable-plugin-autoload with -p pytest_cov.plugin. The plugin is
+    registered under its module name (pytest_cov.plugin) instead of entry point name
+    (pytest_cov) in this scenario.
+    """
+    args = ["--collect-only"]
+    env_add = {"COVERAGE_ENABLED": "True", "_PYTEST_MANUAL_PLUGIN_LOAD": "True"}
+    cov_folder_path = TEST_DATA_PATH / "coverage_gen"
+
+    # Should NOT raise VSCodePytestError about pytest-cov not being installed
+    actual = runner_with_cwd_env(args, cov_folder_path, env_add)
+    assert actual is not None
+    # Verify discovery succeeded (status != "error")
+    assert actual[0].get("status") != "error"

python_files/vscode_pytest/__init__.py

@@ -87,7 +87,9 @@ def __init__(self, message):
 
 
 def pytest_load_initial_conftests(early_config, parser, args):  # noqa: ARG001
-    has_pytest_cov = early_config.pluginmanager.hasplugin("pytest_cov")
+    has_pytest_cov = early_config.pluginmanager.hasplugin(
+        "pytest_cov"
+    ) or early_config.pluginmanager.hasplugin("pytest_cov.plugin")
     has_cov_arg = any("--cov" in arg for arg in args)
     if has_cov_arg and not has_pytest_cov:
         raise VSCodePytestError(