Add lineno to class nodes for unittest discovery

- Modified build_test_tree() in pvsc_utils.py to add line numbers to class nodes
- Added get_class_line() function to extract class line numbers using inspect
- Made lineno an optional field in TestNode TypedDict
- Added find_class_line_number() helper for test expectations
- Updated expected test outputs to include lineno for class nodes

This implements the same functionality for unittest as was done for pytest, enabling TestClass items to show the green arrow and be runnable in VS Code's Test Explorer.

Co-authored-by: eleanorjboyd <26030610+eleanorjboyd@users.noreply.github.com>

Author: Copilot

python_files/tests/unittestadapter/expected_discovery_test_output.py

@@ -9,6 +9,25 @@
 TEST_DATA_PATH = pathlib.Path(__file__).parent / ".data"
 
 
+def find_class_line_number(class_name: str, test_file_path) -> str:
+    """Function which finds the correct line number for a class definition.
+
+    Args:
+    class_name: The name of the class to find the line number for.
+    test_file_path: The path to the test file where the class is located.
+    """
+    # Look for the class definition line
+    with pathlib.Path(test_file_path).open() as f:
+        for i, line in enumerate(f):
+            # Match "class ClassName" or "class ClassName(" or "class ClassName:"
+            if line.strip().startswith(f"class {class_name}") or line.strip().startswith(
+                f"class {class_name}("
+            ):
+                return str(i + 1)
+    error_str: str = f"Class {class_name!r} not found on any line in {test_file_path}"
+    raise ValueError(error_str)
+
+
 skip_unittest_folder_discovery_output = {
     "path": os.fspath(TEST_DATA_PATH / "unittest_skip"),
     "name": "unittest_skip",
@@ -49,6 +68,10 @@
                     ],
                     "id_": os.fspath(TEST_DATA_PATH / "unittest_skip" / "unittest_skip_function.py")
                     + "\\SimpleTest",
+                    "lineno": find_class_line_number(
+                        "SimpleTest",
+                        TEST_DATA_PATH / "unittest_skip" / "unittest_skip_function.py",
+                    ),
                 }
             ],
             "id_": os.fspath(TEST_DATA_PATH / "unittest_skip" / "unittest_skip_function.py"),
@@ -114,6 +137,16 @@
                                         },
                                     ],
                                     "id_": complex_tree_file_path + "\\" + "TreeOne",
+                                    "lineno": find_class_line_number(
+                                        "TreeOne",
+                                        pathlib.PurePath(
+                                            TEST_DATA_PATH,
+                                            "utils_complex_tree",
+                                            "test_outer_folder",
+                                            "test_inner_folder",
+                                            "test_utils_complex_tree.py",
+                                        ),
+                                    ),
                                 }
                             ],
                             "id_": complex_tree_file_path,

python_files/unittestadapter/pvsc_utils.py

@@ -44,6 +44,7 @@ class TestItem(TestData):
 
 class TestNode(TestData):
     children: "List[TestNode | TestItem]"
+    lineno: NotRequired[str]  # Optional field for class nodes
 
 
 class TestExecutionStatus(str, enum.Enum):
@@ -101,6 +102,16 @@ def get_test_case(suite):
             yield from get_test_case(test)
 
 
+def get_class_line(test_case: unittest.TestCase) -> str:
+    """Get the line number where a test class is defined."""
+    try:
+        test_class = test_case.__class__
+        _sourcelines, lineno = inspect.getsourcelines(test_class)
+        return str(lineno)
+    except Exception:
+        return "*"
+
+
 def get_source_line(obj) -> str:
     """Get the line number of a test case start line."""
     try:
@@ -249,6 +260,10 @@ def build_test_tree(
                 class_name, file_path, TestNodeTypeEnum.class_, current_node
             )
 
+            # Add line number to class node if not already present.
+            if "lineno" not in current_node:
+                current_node["lineno"] = get_class_line(test_case)
+
             # Get test line number.
             test_method = getattr(test_case, test_case._testMethodName)  # noqa: SLF001
             lineno = get_source_line(test_method)