actually move to showing empty node and comment fixes

Author: eleanorjboyd

.github/instructions/testing_feature_area.instructions.md

@@ -182,7 +182,7 @@ Project-based testing enables multi-project workspace support where each Python
 4. **Test discovery**: For each project, the controller calls `project.discoveryAdapter.discoverTests()` with the project's URI. The adapter sets `PROJECT_ROOT_PATH` environment variable for the Python runner.
 5. **Python side**:
     - For pytest: `get_test_root_path()` in `vscode_pytest/__init__.py` returns `PROJECT_ROOT_PATH` (if set) or falls back to `cwd`.
-    - For unittest: `discovery.py` uses `PROJECT_ROOT_PATH` as `top_level_dir` and `cwd_override` to root the test tree at the project directory.
+    - For unittest: `discovery.py` uses `PROJECT_ROOT_PATH` as `top_level_dir` and `project_root_path` to root the test tree at the project directory.
 6. **Test tree**: Each project gets its own root node in the Test Explorer, with test IDs scoped by project ID using the `@@vsc@@` separator (defined in `projectUtils.ts`).
 
 ### Nested project handling: pytest vs unittest
@@ -201,9 +201,9 @@ This approach was chosen because:
 2. Implementing custom exclusion would add significant complexity with minimal benefit
 3. The existing approach is transparent and predictable - each project shows what it finds
 
-### Empty projects and hidden root nodes
+### Empty projects and root nodes
 
-**Important:** If a project discovers zero tests, its root node will **not appear** in the Test Explorer. This is by design - the test tree only shows projects that have actual tests.
+If a project discovers zero tests, its root node will still appear in the Test Explorer as an empty folder. This ensures consistent behavior and makes it clear which projects were discovered, even if they have no tests yet.
 
 ### Logging prefix
 
@@ -213,17 +213,17 @@ All project-based testing logs use the `[test-by-project]` prefix for easy filte
 
 -   Python side:
     -   `python_files/vscode_pytest/__init__.py` — `get_test_root_path()` function and `PROJECT_ROOT_PATH` environment variable for pytest.
-    -   `python_files/unittestadapter/discovery.py` — `discover_tests()` with `cwd_override` parameter and `PROJECT_ROOT_PATH` handling for unittest discovery.
-    -   `python_files/unittestadapter/execution.py` — `run_tests()` with `cwd_override` parameter and `PROJECT_ROOT_PATH` handling for unittest execution.
+    -   `python_files/unittestadapter/discovery.py` — `discover_tests()` with `project_root_path` parameter and `PROJECT_ROOT_PATH` handling for unittest discovery.
+    -   `python_files/unittestadapter/execution.py` — `run_tests()` with `project_root_path` parameter and `PROJECT_ROOT_PATH` handling for unittest execution.
 -   TypeScript: `testProjectRegistry.ts`, `projectAdapter.ts`, `projectUtils.ts`, and the discovery/execution adapters.
 
 ### Tests
 
 -   `src/test/testing/testController/common/testProjectRegistry.unit.test.ts` — TestProjectRegistry tests
 -   `src/test/testing/testController/common/projectUtils.unit.test.ts` — Project utility function tests
 -   `python_files/tests/pytestadapter/test_discovery.py` — pytest PROJECT_ROOT_PATH tests (see `test_project_root_path_env_var()` and `test_symlink_with_project_root_path()`)
--   `python_files/tests/unittestadapter/test_discovery.py` — unittest `cwd_override` / PROJECT_ROOT_PATH discovery tests
--   `python_files/tests/unittestadapter/test_execution.py` — unittest `cwd_override` / PROJECT_ROOT_PATH execution tests
+-   `python_files/tests/unittestadapter/test_discovery.py` — unittest `project_root_path` / PROJECT_ROOT_PATH discovery tests
+-   `python_files/tests/unittestadapter/test_execution.py` — unittest `project_root_path` / PROJECT_ROOT_PATH execution tests
 -   `src/test/testing/testController/unittest/testDiscoveryAdapter.unit.test.ts` — unittest discovery adapter PROJECT_ROOT_PATH tests
 -   `src/test/testing/testController/unittest/testExecutionAdapter.unit.test.ts` — unittest execution adapter PROJECT_ROOT_PATH tests
 

python_files/tests/unittestadapter/test_discovery.py

@@ -191,8 +191,7 @@ def test_empty_discovery() -> None:
     actual = discover_tests(start_dir, pattern, None)
 
     assert actual["status"] == "success"
-    # When no tests are found, the tests key should not be present in the payload
-    assert "tests" not in actual
+    assert "tests" in actual
     assert "error" not in actual
 
 
@@ -329,25 +328,25 @@ def test_simple_django_collect():
 
 
 def test_project_root_path_with_cwd_override() -> None:
-    """Test unittest discovery with cwd_override parameter.
+    """Test unittest discovery with project_root_path parameter.
 
     This simulates project-based testing where the cwd in the payload should be
-    the project root (cwd_override) rather than the start_dir.
+    the project root (project_root_path) rather than the start_dir.
 
-    When cwd_override is provided:
-    - The cwd in the response should match cwd_override
+    When project_root_path is provided:
+    - The cwd in the response should match project_root_path
     - The test tree root should still be built correctly based on top_level_dir
     """
     # Use unittest_skip folder as our "project" directory
     project_path = TEST_DATA_PATH / "unittest_skip"
     start_dir = os.fsdecode(project_path)
     pattern = "unittest_*"
 
-    # Call discover_tests with cwd_override to simulate PROJECT_ROOT_PATH
-    actual = discover_tests(start_dir, pattern, None, cwd_override=start_dir)
+    # Call discover_tests with project_root_path to simulate PROJECT_ROOT_PATH
+    actual = discover_tests(start_dir, pattern, None, project_root_path=start_dir)
 
     assert actual["status"] == "success"
-    # cwd in response should match the cwd_override (project root)
+    # cwd in response should match the project_root_path (project root)
     assert actual["cwd"] == os.fsdecode(project_path), (
         f"Expected cwd '{os.fsdecode(project_path)}', got '{actual['cwd']}'"
     )
@@ -362,11 +361,11 @@ def test_project_root_path_with_cwd_override() -> None:
 
 
 def test_project_root_path_with_different_cwd_and_start_dir() -> None:
-    """Test unittest discovery where cwd_override differs from start_dir.
+    """Test unittest discovery where project_root_path differs from start_dir.
 
     This simulates the scenario where:
     - start_dir points to a subfolder where tests are located
-    - cwd_override (PROJECT_ROOT_PATH) points to the project root
+    - project_root_path (PROJECT_ROOT_PATH) points to the project root
 
     The cwd in the response should be the project root, while discovery
     still runs from the start_dir.
@@ -384,11 +383,11 @@ def test_project_root_path_with_different_cwd_and_start_dir() -> None:
     pattern = "test_*.py"
     top_level_dir = os.fsdecode(project_path)
 
-    # Call discover_tests with cwd_override set to project root
-    actual = discover_tests(start_dir, pattern, top_level_dir, cwd_override=top_level_dir)
+    # Call discover_tests with project_root_path set to project root
+    actual = discover_tests(start_dir, pattern, top_level_dir, project_root_path=top_level_dir)
 
     assert actual["status"] == "success"
-    # cwd should be the project root (cwd_override), not the start_dir
+    # cwd should be the project root (project_root_path), not the start_dir
     assert actual["cwd"] == os.fsdecode(project_path), (
         f"Expected cwd '{os.fsdecode(project_path)}', got '{actual['cwd']}'"
     )
@@ -410,29 +409,29 @@ def test_symlink_with_project_root_path() -> None:
 
     This tests the combination of:
     1. A symlinked test directory
-    2. cwd_override (PROJECT_ROOT_PATH) set to the symlink path
+    2. project_root_path (PROJECT_ROOT_PATH) set to the symlink path
 
     This simulates project-based testing where the project root is a symlink,
     ensuring test IDs and paths are correctly resolved through the symlink.
     """
     with helpers.create_symlink(TEST_DATA_PATH, "unittest_skip", "symlink_unittest") as (
-        source,
+        _source,
         destination,
     ):
         assert destination.is_symlink()
 
         # Run discovery with:
         # - start_dir pointing to the symlink destination
-        # - cwd_override set to the symlink destination (simulating PROJECT_ROOT_PATH)
+        # - project_root_path set to the symlink destination (simulating PROJECT_ROOT_PATH)
         start_dir = os.fsdecode(destination)
         pattern = "unittest_*"
 
-        actual = discover_tests(start_dir, pattern, None, cwd_override=start_dir)
+        actual = discover_tests(start_dir, pattern, None, project_root_path=start_dir)
 
         assert actual["status"] == "success", (
             f"Status is not 'success', error is: {actual.get('error')}"
         )
-        # cwd should be the symlink path (cwd_override)
+        # cwd should be the symlink path (project_root_path)
         assert actual["cwd"] == os.fsdecode(destination), (
             f"CWD does not match symlink path: expected {os.fsdecode(destination)}, got {actual['cwd']}"
         )

python_files/tests/unittestadapter/test_execution.py

@@ -344,13 +344,13 @@ def test_basic_run_django():
 
 
 def test_project_root_path_with_cwd_override(mock_send_run_data) -> None:  # noqa: ARG001
-    """Test unittest execution with cwd_override parameter.
+    """Test unittest execution with project_root_path parameter.
 
     This simulates project-based testing where the cwd in the payload should be
-    the project root (cwd_override) rather than the start_dir.
+    the project root (project_root_path) rather than the start_dir.
 
-    When cwd_override is provided:
-    - The cwd in the response should match cwd_override
+    When project_root_path is provided:
+    - The cwd in the response should match project_root_path
     - Test execution should still work correctly with start_dir
     """
     # Use unittest_folder as our "project" directory
@@ -363,19 +363,19 @@ def test_project_root_path_with_cwd_override(mock_send_run_data) -> None:  # noq
 
     os.environ["TEST_RUN_PIPE"] = "fake"
 
-    # Call run_tests with cwd_override to simulate PROJECT_ROOT_PATH
+    # Call run_tests with project_root_path to simulate PROJECT_ROOT_PATH
     actual = run_tests(
         start_dir,
         test_ids,
         pattern,
         None,
         1,
         None,
-        cwd_override=start_dir,
+        project_root_path=start_dir,
     )
 
     assert actual["status"] == "success"
-    # cwd in response should match the cwd_override (project root)
+    # cwd in response should match the project_root_path (project root)
     assert actual["cwd"] == os.fsdecode(project_path), (
         f"Expected cwd '{os.fsdecode(project_path)}', got '{actual['cwd']}'"
     )
@@ -384,12 +384,12 @@ def test_project_root_path_with_cwd_override(mock_send_run_data) -> None:  # noq
     assert actual["result"][test_ids[0]]["outcome"] == "success"
 
 
-def test_project_root_path_with_different_cwd_and_start_dir() -> None:
-    """Test unittest execution where cwd_override differs from start_dir.
+def test_project_root_path_with_different_cwd_and_start_dir(mock_send_run_data) -> None:  # noqa: ARG001
+    """Test unittest execution where project_root_path differs from start_dir.
 
     This simulates the scenario where:
     - start_dir points to a subfolder where tests are located
-    - cwd_override (PROJECT_ROOT_PATH) points to the project root
+    - project_root_path (PROJECT_ROOT_PATH) points to the project root
 
     The cwd in the response should be the project root, while execution
     still runs from the start_dir.
@@ -404,19 +404,19 @@ def test_project_root_path_with_different_cwd_and_start_dir() -> None:
 
     os.environ["TEST_RUN_PIPE"] = "fake"
 
-    # Call run_tests with cwd_override set to project root
+    # Call run_tests with project_root_path set to project root
     actual = run_tests(
         start_dir,
         test_ids,
         pattern,
         None,
         1,
         None,
-        cwd_override=os.fsdecode(project_path),
+        project_root_path=os.fsdecode(project_path),
     )
 
     assert actual["status"] == "success"
-    # cwd should be the project root (cwd_override)
+    # cwd should be the project root (project_root_path)
     assert actual["cwd"] == os.fsdecode(project_path), (
         f"Expected cwd '{os.fsdecode(project_path)}', got '{actual['cwd']}'"
     )
@@ -429,11 +429,11 @@ def test_project_root_path_with_different_cwd_and_start_dir() -> None:
     reason="Symlinks require elevated privileges on Windows",
 )
 def test_symlink_with_project_root_path(mock_send_run_data) -> None:  # noqa: ARG001
-    """Test unittest execution with both symlink and cwd_override set.
+    """Test unittest execution with both symlink and project_root_path set.
 
     This tests the combination of:
     1. A symlinked test directory
-    2. cwd_override (PROJECT_ROOT_PATH) set to the symlink path
+    2. project_root_path (PROJECT_ROOT_PATH) set to the symlink path
 
     This simulates project-based testing where the project root is a symlink,
     ensuring execution payloads correctly use the symlink path.
@@ -446,7 +446,7 @@ def test_symlink_with_project_root_path(mock_send_run_data) -> None:  # noqa: AR
 
         # Run execution with:
         # - start_dir pointing to the symlink destination
-        # - cwd_override set to the symlink destination (simulating PROJECT_ROOT_PATH)
+        # - project_root_path set to the symlink destination (simulating PROJECT_ROOT_PATH)
         start_dir = os.fsdecode(destination)
         pattern = "test_add*"
         test_ids = [
@@ -462,13 +462,13 @@ def test_symlink_with_project_root_path(mock_send_run_data) -> None:  # noqa: AR
             None,
             1,
             None,
-            cwd_override=start_dir,
+            project_root_path=start_dir,
         )
 
         assert actual["status"] == "success", (
             f"Status is not 'success', error is: {actual.get('error')}"
         )
-        # cwd should be the symlink path (cwd_override)
+        # cwd should be the symlink path (project_root_path)
         assert actual["cwd"] == os.fsdecode(destination), (
             f"CWD does not match symlink path: expected {os.fsdecode(destination)}, got {actual['cwd']}"
         )

python_files/unittestadapter/discovery.py

@@ -27,13 +27,13 @@ def discover_tests(
     start_dir: str,
     pattern: str,
     top_level_dir: Optional[str],
-    cwd_override: Optional[str] = None,
+    project_root_path: Optional[str] = None,
 ) -> DiscoveryPayloadDict:
     """Returns a dictionary containing details of the discovered tests.
 
     The returned dict has the following keys:
 
-    - cwd: Absolute path to the test start directory (or cwd_override if provided);
+    - cwd: Absolute path to the test start directory (or project_root_path if provided);
     - status: Test discovery status, can be "success" or "error";
     - tests: Discoverered tests if any, not present otherwise. Note that the status can be "error" but the payload can still contain tests;
     - error: Discovery error if any, not present otherwise.
@@ -62,10 +62,10 @@ def discover_tests(
         start_dir: Directory where test discovery starts
         pattern: Pattern to match test files (e.g., "test*.py")
         top_level_dir: Top-level directory for the test tree hierarchy
-        cwd_override: Optional override for the cwd in the response payload
-                     (used for project-based testing to set project root)
+        project_root_path: Optional project root path for the cwd in the response payload
+                          (used for project-based testing to root test tree at project)
     """
-    cwd = os.path.abspath(cwd_override if cwd_override else start_dir)  # noqa: PTH100
+    cwd = os.path.abspath(project_root_path or start_dir)  # noqa: PTH100
     if "/" in start_dir:  #  is a subdir
         parent_dir = os.path.dirname(start_dir)  # noqa: PTH120
         sys.path.insert(0, parent_dir)
@@ -91,10 +91,9 @@ def discover_tests(
     except Exception:
         error.append(traceback.format_exc())
 
-    # Only include tests in the payload if tests were discovered.
-    # If no tests found (tests is None), omit the tests key per the docstring contract.
-    if tests is not None:
-        payload["tests"] = tests
+    # Still include the tests in the payload even if there are errors so that the TS
+    # side can determine if it is from run or discovery.
+    payload["tests"] = tests if tests is not None else None
 
     if len(error):
         payload["status"] = "error"
@@ -152,7 +151,9 @@ def discover_tests(
             )
 
         # Perform regular unittest test discovery.
-        # Pass project_root_path as cwd_override so the payload's cwd matches the project root.
-        payload = discover_tests(start_dir, pattern, top_level_dir, cwd_override=project_root_path)
+        # Pass project_root_path so the payload's cwd matches the project root.
+        payload = discover_tests(
+            start_dir, pattern, top_level_dir, project_root_path=project_root_path
+        )
         # Post this discovery payload.
         send_post_request(payload, test_run_pipe)

python_files/unittestadapter/execution.py

@@ -194,7 +194,7 @@ def run_tests(
     verbosity: int,
     failfast: Optional[bool],  # noqa: FBT001
     locals_: Optional[bool] = None,  # noqa: FBT001
-    cwd_override: Optional[str] = None,
+    project_root_path: Optional[str] = None,
 ) -> ExecutionPayloadDict:
     """Run unittests and return the execution payload.
 
@@ -206,10 +206,10 @@ def run_tests(
         verbosity: Verbosity level for test output
         failfast: Stop on first failure
         locals_: Show local variables in tracebacks
-        cwd_override: Optional override for the cwd in the response payload
-                     (used for project-based testing to set project root)
+        project_root_path: Optional project root path for the cwd in the response payload
+                          (used for project-based testing to root test tree at project)
     """
-    cwd = os.path.abspath(cwd_override or start_dir)  # noqa: PTH100
+    cwd = os.path.abspath(project_root_path or start_dir)  # noqa: PTH100
     if "/" in start_dir:  #  is a subdir
         parent_dir = os.path.dirname(start_dir)  # noqa: PTH120
         sys.path.insert(0, parent_dir)
@@ -378,7 +378,7 @@ def send_run_data(raw_data, test_run_pipe):
             )
 
         # Perform regular unittest execution.
-        # Pass project_root_path as cwd_override so the payload's cwd matches the project root.
+        # Pass project_root_path so the payload's cwd matches the project root.
         payload = run_tests(
             start_dir,
             test_ids,
@@ -387,7 +387,7 @@ def send_run_data(raw_data, test_run_pipe):
             verbosity,
             failfast,
             locals_,
-            cwd_override=project_root_path,
+            project_root_path=project_root_path,
         )
 
     if is_coverage_run:

python_files/unittestadapter/pvsc_utils.py

@@ -281,10 +281,6 @@ def build_test_tree(
             }  # concatenate class name and function test name
             current_node["children"].append(test_node)
 
-    # If no tests were discovered, return None instead of an empty root node
-    if not root["children"]:
-        return None, error
-
     return root, error