Speed up testcase decoration by avoiding inspect.getsourcelines and avoid repeated calls for LocationMetadata.from_object

doc/newsfragments/3828_changed.speedup_testplan_startup.rst

@@ -0,0 +1 @@
+Speed up testplan startup by avoiding repeated source-file tokenization in ``LocationMetadata.from_object``: functions now resolve their location directly from ``__code__``, and parametrized testcases reuse a single template lookup across all generated variants.

testplan/testing/multitest/suite.py

@@ -693,6 +693,10 @@ def wrapper(function: Any) -> Any:
                 raise err
 
             # Register generated functions as testcases
+            template_location = TestCaseStaticMetadata(
+                LocationMetadata.from_object(function)
+            )
+
             for func in functions:
                 # this has to be called before wrappers otherwise wrappers can
                 # fail if they rely on ``__testcase__``
@@ -710,12 +714,7 @@ def wrapper(function: Any) -> Any:
 
                 __GENERATED_TESTCASES__.append(func)
 
-                add_testcase_metadata(
-                    func,
-                    TestCaseStaticMetadata(
-                        LocationMetadata.from_object(function)
-                    ),
-                )
+                add_testcase_metadata(func, template_location)
 
             return function
 

testplan/testing/multitest/test_metadata.py

@@ -19,12 +19,19 @@ def from_object(cls, obj: object) -> Optional["LocationMetadata"]:
             return getattr(obj, LOCATION_METADATA_ATTRIBUTE)  # type: ignore[no-any-return]
         try:
             object_name = obj.__name__  # type: ignore[attr-defined]
-            file = getsourcefile(obj)  # type: ignore[arg-type]
-            _, line_no = getsourcelines(obj)  # type: ignore[arg-type]
+            code = getattr(obj, "__code__", None)
+            if code is not None:
+                # Functions expose the defining file and first line directly
+                # on their code object — no file I/O or tokenization needed.
+                file = code.co_filename or ""
+                line_no = code.co_firstlineno
+            else:
+                file = getsourcefile(obj)  # type: ignore[arg-type]
+                _, line_no = getsourcelines(obj)  # type: ignore[arg-type]
         except Exception:
             return None  # we do best effort here
-        else:
-            return cls(object_name, file or "", line_no)
+
+        return cls(object_name, file, line_no)
 
 
 @dataclass

tests/unit/testplan/testing/multitest/test_suite.py

@@ -1,13 +1,15 @@
 """Unit tests for the testplan.testing.multitest.suite module."""
 
 import re
+from unittest import mock
 
 import pytest
 
 from testplan.common.utils.exceptions import should_raise
 from testplan.common.utils.interface import MethodSignatureMismatch
 from testplan.common.utils.strings import format_description
-from testplan.testing.multitest import suite
+from testplan.testing.multitest import suite, test_metadata
+from testplan.testing.multitest.test_metadata import LocationMetadata
 from testplan.testing import tagging
 
 
@@ -248,3 +250,47 @@ def test_skip_if_signature():
 )
 def test_format_description(text, expected):
     format_description(text) == expected
+
+
+def _location_sample_function(self, env, result):
+    pass
+
+
+def test_from_object_function_skips_getsourcelines():
+    with (
+        mock.patch.object(
+            test_metadata, "getsourcelines"
+        ) as mocked_getsourcelines,
+        mock.patch.object(
+            test_metadata, "getsourcefile"
+        ) as mocked_getsourcefile,
+    ):
+        LocationMetadata.from_object(_location_sample_function)
+
+    mocked_getsourcelines.assert_not_called()
+    mocked_getsourcefile.assert_not_called()
+
+
+def test_parametrization_template_inspected_once():
+    real_from_object = LocationMetadata.from_object
+    template_calls = []
+
+    def tracking_from_object(obj):
+        if getattr(obj, "__name__", None) == "case":
+            template_calls.append(obj)
+        return real_from_object(obj)
+
+    with mock.patch.object(
+        LocationMetadata, "from_object", side_effect=tracking_from_object
+    ):
+
+        @suite.testsuite
+        class ParamSuite:
+            @suite.testcase(parameters=[range(3)])
+            def case(self, env, result, value):
+                pass
+
+    assert len(template_calls) == 1, (
+        "Parametrization template should be inspected once across all "
+        f"variants; got {len(template_calls)} calls"
+    )