Merge branch '216-black-lambda-parsing-2' into 'main'

Handle unnamed lambdas in function analysis to avoid crash on export

Closes #216

See merge request se2/pynguin/pynguin!254

Author: stephanlukasczyk

src/pynguin/analyses/module.py

@@ -1146,17 +1146,17 @@ def __analyse_function(
     description = get_function_description(func_ast)
     raised_exceptions = description.raises if description is not None else set()
     cyclomatic_complexity = __get_mccabe_complexity(func_ast)
-    if (
-        getattr(func, "__name__", None) == "<lambda>"
-        and (
-            lambda_assigned_name := _get_lambda_assigned_name(
-                module_tree, func.__code__.co_firstlineno
-            )
-        )
-        is not None
-    ):
-        func_name = lambda_assigned_name
-        func.__name__ = lambda_assigned_name
+    if getattr(func, "__name__", None) == "<lambda>":
+        if lambda_assigned_name := _get_lambda_assigned_name(
+            module_tree, func.__code__.co_firstlineno
+        ):
+            func_name = lambda_assigned_name
+            func.__name__ = lambda_assigned_name
+        else:
+            # If the lambda itself has no name, we must not add it to the test cluster
+            # or else it will cause an exception during test export.
+            return
+
     generic_function = GenericFunction(func, inferred_signature, raised_exceptions, func_name)
 
     if config.configuration.pynguinml.ml_testing_enabled and module_tree is not None:

tests/analyses/test_module.py

@@ -64,6 +64,11 @@ def parsed_module_lambda() -> _ModuleParseResult:
     return parse_module("tests.fixtures.cluster.lambda")
 
 
+@pytest.fixture(scope="module")
+def parsed_module_unnamed_lambda() -> _ModuleParseResult:
+    return parse_module("tests.fixtures.cluster.unnamed_lambda")
+
+
 @pytest.fixture
 def module_test_cluster() -> ModuleTestCluster:
     return ModuleTestCluster(linenos=-1)
@@ -572,3 +577,27 @@ def test_analyse_module_lambda(parsed_module_lambda):
     assert lambda2.function_name == "abc"
     lambda3 = cast("GenericFunction", objects[2])
     assert lambda3.function_name == "salam_aleykum"
+
+
+def test_analyse_function_lambda_no_name():
+    """Test that __analyse_function returns early when no name for a lambda is found."""
+    # Create a test cluster
+    test_cluster = ModuleTestCluster(linenos=-1)
+
+    # Create a lambda function
+    lambda_func = lambda x: x  # noqa: E731
+
+    # Mock the _get_lambda_assigned_name function to return None
+    with patch("pynguin.analyses.module._get_lambda_assigned_name", return_value=None):
+        # Call __analyse_function directly
+        module.__analyse_function(
+            func_name="<lambda>",
+            func=lambda_func,
+            type_inference_strategy=TypeInferenceStrategy.TYPE_HINTS,
+            module_tree=None,
+            test_cluster=test_cluster,
+            add_to_test=True,
+        )
+
+    # Verify that the lambda was not added to the test cluster
+    assert test_cluster.num_accessible_objects_under_test() == 0