Add line number support for class nodes in pytest and unittest (#25593)

## Plan: Add Location to TestClass Items for Run Functionality

This PR implements the fix for issue #25592 - TestClass items need a
location (lineno) to be runnable and show the green arrow in VS Code's
Test Explorer.

### Changes Completed:

#### Pytest:
- [x] Update Python pytest adapter to add `lineno` field to class nodes
- [x] Modify `create_class_node()` in
`python_files/vscode_pytest/__init__.py` to extract and include line
number
  - [x] Update TypeScript types to allow `lineno` on class nodes
  - [x] Fix Python type checking errors
  
- [x] Update expected test outputs
- [x] Update all expected discovery outputs in
`python_files/tests/pytestadapter/expected_discovery_test_output.py` to
include `lineno` for class nodes
  - [x] Add `find_class_line_number()` helper function

#### Unittest:
- [x] Update Python unittest adapter to add `lineno` field to class
nodes
- [x] Modify `build_test_tree()` in
`python_files/unittestadapter/pvsc_utils.py` to add line numbers
  - [x] Add `get_class_line()` function to extract class line numbers
  - [x] Make `lineno` optional field in `TestNode` TypedDict
- [x] Return empty string instead of "*" when line cannot be determined
  
- [x] Update expected test outputs
- [x] Update expected discovery outputs in
`python_files/tests/unittestadapter/expected_discovery_test_output.py`
to include `lineno` for class nodes
  - [x] Add `find_class_line_number()` helper function

#### TypeScript:
- [x] Update TypeScript result resolver
- [x] Modify `populateTestTree()` in
`src/client/testing/testController/common/utils.ts` to handle `lineno`
for class nodes
- [x] Update type definitions to allow optional `lineno` on
`DiscoveredTestNode`
  - [x] Add 'function' to `DiscoveredTestType` enum

### Test Results:

**Pytest tests:** ✅ 13/15 passing (2 failures expected - pytest-describe
plugin not installed)
**Unittest tests:** ✅ Verified class nodes include lineno

**Code quality:**
- ✅ Ruff formatting and linting passed
- ⚠️ Pyright has pre-existing errors (not introduced by this change)

### Technical Implementation:

**Pytest:**
- Extract line number from pytest.Class objects using Python's
`inspect.getsourcelines()`
- Add `lineno` as optional field to TestNode TypedDict (using
NotRequired)
- Return empty string when line number cannot be determined

**Unittest:**
- Extract line number from test_case.__class__ using
`inspect.getsourcelines()`
- Add `lineno` field to class nodes during tree building
- Use same optional field pattern in TestNode TypedDict
- Return empty string when line number cannot be determined (consistent
with pytest)

**TypeScript:**
- Create VS Code ranges for class nodes when `lineno` is present

This minimal change ensures TestClass items are treated similarly to
test items in terms of having a location, making them runnable in the VS
Code UI for both pytest and unittest.

<!-- START COPILOT CODING AGENT SUFFIX -->



<details>

<summary>Original prompt</summary>

fantastic analysis. Please implement this and keep in mind all this
context you have; both how this should be done, what should be changed,
and how tests are impacted

<analysis>
[Chronological Review: The conversation began with the user requesting a
discussion about issue #25592 on GitHub, specifically regarding the need
for TestClass items to have a location for proper functionality. The
user then asked about the risks associated with this change and which
tests would need updating. Following a positive response to the
analysis, the user requested implementation of the discussed changes
while considering the context of how it should be done, what should be
changed, and how tests are impacted.]

[Intent Mapping: 
1. "lets talk about this issue:
#25592 what needs to be
done (likely) is TestClass items need a location so it shows as the
green arrow and makes it runnable." - User wants to discuss the issue
and create a plan for implementation.
2. "what risk does this change have? what tests will need to be
updated?" - User seeks to understand the implications of the changes and
necessary test updates.
3. "fantastic analysis. Please implement this and keep in mind all this
context you have; both how this should be done, what should be changed,
and how tests are impacted." - User requests implementation of the
analysis with a focus on context and impact.]

[Technical Inventory: 
- Repository: vscode-python
- Current Branch: supposed-spoonbill
- Default Branch: main
- Active Pull Request: support extra patching for doctest
(#25591)
- Issue Discussed: #25592 regarding TestClass items needing a location.]

[Code Archaeology: No specific files or code changes were discussed in
detail, but the focus was on the functionality of TestClass items and
their integration into the existing codebase.]

[Progress Assessment: 
- Completed Tasks: Analysis of the issue and identification of necessary
changes.
- Partially Complete Work: Implementation of the discussed changes is
pending.
- Validated Outcomes: None yet, as implementation has not been
executed.]

[Context Validation: All critical information for continuation is
captured, including the need for changes to TestClass items and the
implications for testing.]

[Recent Commands Analysis: 
- Last Agent Commands: User requested a plan for the issue, an analysis
of risks, and implementation of the discussed changes.
- Tool Results Summary: No specific tool results were returned as the
conversation focused on planning and analysis rather than executing code
or commands.
- Pre-Summary State: The agent was actively discussing the
implementation of changes related to issue #25592 when the token budget
was exceeded.
- Operation Context: The commands were executed to align with the user's
goals of addressing the issue and ensuring proper functionality of
TestClass items.]

</analysis>

<summary>
1. Conversation Overview:
- Primary Objectives: The user aimed to discuss issue #25592, focusing
on making TestClass items runnable by providing them with a location.
The user also sought to understand the risks and necessary test updates
related to this change.
- Session Context: The conversation flowed from discussing the issue,
analyzing risks, and finally requesting implementation of the proposed
changes.
- User Intent Evolution: The user transitioned from seeking information
and analysis to requesting concrete implementation of the discussed
changes.

2. Technical Foundation:
- Repository: vscode-python
- Current Branch: supposed-spoonbill
- Default Branch: main
- Active Pull Request: support extra patching for doctest
(#25591)

3. Codebase Status:
- No specific files were modified or discussed in detail, but the focus
was on the functionality of TestClass items.

4. Problem Resolution:
- Issues Encountered: The need for TestClass items to have a location
for proper functionality.
- Solutions Implemented: Analysis of the issue and identification of
necessary changes were completed, but implementation is pending.
- Debugging Context: No ongoing troubleshooting efforts were mentioned.
- Lessons Learned: Understanding the implications of changes on existing
functionality and tests is crucial.

5. Progress Tracking:
- Completed Tasks: Analysis of the issue and identification of necessary
changes.
- Partially Complete Work: Implementation of the discussed changes is
pending.
- Validated Outcomes: None yet, as implementation has not been executed.

6. Active Work State:
- Current Focus: The user was focused on implementing changes related to
issue #25592.
- Recent Context: The last few exchanges involved discussing the issue,
analyzing risks, and planning for implementation.
- Working Code: No specific code snippets were discussed recently.
- Immediate Context: The specific problem being addressed was the need
for TestClass items to have a locat...

</details>

Created from [VS
Code](https://code.visualstudio.com/docs/copilot/copilot-coding-agent).

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>

Author: eleanorjboyd

python_files/tests/pytestadapter/expected_discovery_test_output.py

@@ -1,6 +1,11 @@
 import os
 
-from .helpers import TEST_DATA_PATH, find_test_line_number, get_absolute_test_id
+from .helpers import (
+    TEST_DATA_PATH,
+    find_class_line_number,
+    find_test_line_number,
+    get_absolute_test_id,
+)
 
 # This file contains the expected output dictionaries for tests discovery and is used in test_discovery.py.
 
@@ -95,6 +100,7 @@
                         "unittest_pytest_same_file.py::TestExample",
                         unit_pytest_same_file_path,
                     ),
+                    "lineno": find_class_line_number("TestExample", unit_pytest_same_file_path),
                 },
                 {
                     "name": "test_true_pytest",
@@ -207,6 +213,7 @@
                                 "unittest_folder/test_add.py::TestAddFunction",
                                 test_add_path,
                             ),
+                            "lineno": find_class_line_number("TestAddFunction", test_add_path),
                         },
                         {
                             "name": "TestDuplicateFunction",
@@ -235,6 +242,9 @@
                                 "unittest_folder/test_add.py::TestDuplicateFunction",
                                 test_add_path,
                             ),
+                            "lineno": find_class_line_number(
+                                "TestDuplicateFunction", test_add_path
+                            ),
                         },
                     ],
                 },
@@ -288,6 +298,9 @@
                                 "unittest_folder/test_subtract.py::TestSubtractFunction",
                                 test_subtract_path,
                             ),
+                            "lineno": find_class_line_number(
+                                "TestSubtractFunction", test_subtract_path
+                            ),
                         },
                         {
                             "name": "TestDuplicateFunction",
@@ -316,6 +329,9 @@
                                 "unittest_folder/test_subtract.py::TestDuplicateFunction",
                                 test_subtract_path,
                             ),
+                            "lineno": find_class_line_number(
+                                "TestDuplicateFunction", test_subtract_path
+                            ),
                         },
                     ],
                 },
@@ -553,6 +569,7 @@
                         "parametrize_tests.py::TestClass",
                         parameterize_tests_path,
                     ),
+                    "lineno": find_class_line_number("TestClass", parameterize_tests_path),
                     "children": [
                         {
                             "name": "test_adding",
@@ -929,6 +946,7 @@
                         "test_multi_class_nest.py::TestFirstClass",
                         TEST_MULTI_CLASS_NEST_PATH,
                     ),
+                    "lineno": find_class_line_number("TestFirstClass", TEST_MULTI_CLASS_NEST_PATH),
                     "children": [
                         {
                             "name": "TestSecondClass",
@@ -938,6 +956,9 @@
                                 "test_multi_class_nest.py::TestFirstClass::TestSecondClass",
                                 TEST_MULTI_CLASS_NEST_PATH,
                             ),
+                            "lineno": find_class_line_number(
+                                "TestSecondClass", TEST_MULTI_CLASS_NEST_PATH
+                            ),
                             "children": [
                                 {
                                     "name": "test_second",
@@ -982,6 +1003,9 @@
                                 "test_multi_class_nest.py::TestFirstClass::TestSecondClass2",
                                 TEST_MULTI_CLASS_NEST_PATH,
                             ),
+                            "lineno": find_class_line_number(
+                                "TestSecondClass2", TEST_MULTI_CLASS_NEST_PATH
+                            ),
                             "children": [
                                 {
                                     "name": "test_second2",
@@ -1227,6 +1251,9 @@
                         "same_function_new_class_param.py::TestNotEmpty",
                         TEST_DATA_PATH / "same_function_new_class_param.py",
                     ),
+                    "lineno": find_class_line_number(
+                        "TestNotEmpty", TEST_DATA_PATH / "same_function_new_class_param.py"
+                    ),
                 },
                 {
                     "name": "TestEmpty",
@@ -1298,6 +1325,9 @@
                         "same_function_new_class_param.py::TestEmpty",
                         TEST_DATA_PATH / "same_function_new_class_param.py",
                     ),
+                    "lineno": find_class_line_number(
+                        "TestEmpty", TEST_DATA_PATH / "same_function_new_class_param.py"
+                    ),
                 },
             ],
         }
@@ -1371,6 +1401,9 @@
                         "test_param_span_class.py::TestClass1",
                         TEST_DATA_PATH / "test_param_span_class.py",
                     ),
+                    "lineno": find_class_line_number(
+                        "TestClass1", TEST_DATA_PATH / "test_param_span_class.py"
+                    ),
                 },
                 {
                     "name": "TestClass2",
@@ -1427,6 +1460,9 @@
                         "test_param_span_class.py::TestClass2",
                         TEST_DATA_PATH / "test_param_span_class.py",
                     ),
+                    "lineno": find_class_line_number(
+                        "TestClass2", TEST_DATA_PATH / "test_param_span_class.py"
+                    ),
                 },
             ],
         }
@@ -1503,6 +1539,7 @@
                                 "pytest_describe_plugin/describe_only.py::describe_A",
                                 describe_only_path,
                             ),
+                            "lineno": find_class_line_number("describe_A", describe_only_path),
                         }
                     ],
                 }
@@ -1586,6 +1623,9 @@
                                         "pytest_describe_plugin/nested_describe.py::describe_list::describe_append",
                                         nested_describe_path,
                                     ),
+                                    "lineno": find_class_line_number(
+                                        "describe_append", nested_describe_path
+                                    ),
                                 },
                                 {
                                     "name": "describe_remove",
@@ -1614,12 +1654,16 @@
                                         "pytest_describe_plugin/nested_describe.py::describe_list::describe_remove",
                                         nested_describe_path,
                                     ),
+                                    "lineno": find_class_line_number(
+                                        "describe_remove", nested_describe_path
+                                    ),
                                 },
                             ],
                             "id_": get_absolute_test_id(
                                 "pytest_describe_plugin/nested_describe.py::describe_list",
                                 nested_describe_path,
                             ),
+                            "lineno": find_class_line_number("describe_list", nested_describe_path),
                         }
                     ],
                 }

python_files/tests/pytestadapter/helpers.py

@@ -370,6 +370,28 @@ def find_test_line_number(test_name: str, test_file_path) -> str:
     raise ValueError(error_str)
 
 
+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 (or function for pytest-describe)
+    with open(test_file_path) as f:  # noqa: PTH123
+        for i, line in enumerate(f):
+            # Match "class ClassName" or "class ClassName(" or "class ClassName:"
+            # Also match "def ClassName(" for pytest-describe blocks
+            if (
+                line.strip().startswith(f"class {class_name}")
+                or line.strip().startswith(f"class {class_name}(")
+                or line.strip().startswith(f"def {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)
+
+
 def get_absolute_test_id(test_id: str, test_path: pathlib.Path) -> str:
     """Get the absolute test id by joining the testPath with the test_id."""
     split_id = test_id.split("::")[1:]

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) -> Optional[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 None
+
+
 def get_source_line(obj) -> str:
     """Get the line number of a test case start line."""
     try:
@@ -249,6 +260,12 @@ 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:
+                class_lineno = get_class_line(test_case)
+                if class_lineno is not None:
+                    current_node["lineno"] = class_lineno
+
             # Get test line number.
             test_method = getattr(test_case, test_case._testMethodName)  # noqa: SLF001
             lineno = get_source_line(test_method)

python_files/vscode_pytest/__init__.py

@@ -10,9 +10,19 @@
 import pathlib
 import sys
 import traceback
-from typing import TYPE_CHECKING, Any, Dict, Generator, Literal, Protocol, TypedDict, cast
+from typing import (
+    TYPE_CHECKING,
+    Any,
+    Dict,
+    Generator,
+    Literal,
+    Protocol,
+    TypedDict,
+    cast,
+)
 
 import pytest
+from typing_extensions import NotRequired
 
 if TYPE_CHECKING:
     from pluggy import Result
@@ -52,6 +62,7 @@ class TestNode(TestData):
     """A general class that handles all test data which contains children."""
 
     children: list[TestNode | TestItem | None]
+    lineno: NotRequired[str]  # Optional field for class/function nodes
 
 
 class VSCodePytestError(Exception):
@@ -830,12 +841,25 @@ def create_class_node(class_module: pytest.Class | DescribeBlock) -> TestNode:
     Keyword arguments:
     class_module -- the pytest object representing a class module.
     """
+    # Get line number for the class definition
+    class_line = ""
+    try:
+        if hasattr(class_module, "obj"):
+            import inspect
+
+            _, lineno = inspect.getsourcelines(class_module.obj)
+            class_line = str(lineno)
+    except (OSError, TypeError):
+        # If we can't get the source lines, leave lineno empty
+        pass
+
     return {
         "name": class_module.name,
         "path": get_node_path(class_module),
         "type_": "class",
         "children": [],
         "id_": get_absolute_test_id(class_module.nodeid, get_node_path(class_module)),
+        "lineno": class_line,
     }
 
 

src/client/testing/testController/common/types.ts

@@ -177,7 +177,7 @@ export interface ITestExecutionAdapter {
 }
 
 // Same types as in python_files/unittestadapter/utils.py
-export type DiscoveredTestType = 'folder' | 'file' | 'class' | 'test';
+export type DiscoveredTestType = 'folder' | 'file' | 'class' | 'function' | 'test';
 
 export type DiscoveredTestCommon = {
     path: string;
@@ -194,6 +194,7 @@ export type DiscoveredTestItem = DiscoveredTestCommon & {
 
 export type DiscoveredTestNode = DiscoveredTestCommon & {
     children: (DiscoveredTestNode | DiscoveredTestItem)[];
+    lineno?: number | string;
 };
 
 export type DiscoveredTestPayload = {

src/client/testing/testController/common/utils.ts

@@ -257,6 +257,21 @@ export function populateTestTree(
 
                     node.canResolveChildren = true;
                     node.tags = [RunTestTag, DebugTestTag];
+
+                    // Set range for class nodes (and other nodes) if lineno is available
+                    let range: Range | undefined;
+                    if ('lineno' in child && child.lineno) {
+                        if (Number(child.lineno) === 0) {
+                            range = new Range(new Position(0, 0), new Position(0, 0));
+                        } else {
+                            range = new Range(
+                                new Position(Number(child.lineno) - 1, 0),
+                                new Position(Number(child.lineno), 0),
+                            );
+                        }
+                        node.range = range;
+                    }
+
                     testRoot!.children.add(node);
                 }
                 populateTestTree(testController, child, node, resultResolver, token);