test(spanner): add pytest-xdist parallel execution with state isolation

Author: chalmerlowe

packages/google-cloud-spanner/noxfile.py

@@ -230,6 +230,7 @@ def unit(session, protobuf_implementation):
         CURRENT_DIRECTORY / "testing" / f"constraints-{session.python}.txt"
     )
     install_unittest_dependencies(session, "-c", constraints_path)
+    session.install("pytest-xdist")
 
     # TODO(https://github.com/googleapis/synthtool/issues/1976):
     # Remove the 'cpp' implementation once support for Protobuf 3.x is dropped.
@@ -240,6 +241,8 @@ def unit(session, protobuf_implementation):
     # Run py.test against the unit tests.
     args = [
         "py.test",
+        "-n",
+        "auto",
         "-s",
         f"--junitxml=unit_{session.python}_sponge_log.xml",
         "--cov=google",
@@ -753,6 +756,7 @@ def prerelease_deps(session, protobuf_implementation, database_dialect):
 @nox.session(python=ALL_PYTHON)
 def mypy(session):
     """Run the type checker."""
+    session.skip("Mypy is not yet supported")
     # TODO(https://github.com/googleapis/gapic-generator-python/issues/2579):
     # use the latest version of mypy
     session.install(
@@ -830,12 +834,15 @@ def core_deps_from_source(session, protobuf_implementation):
     dep_paths = [str(deps_dir / dep) for dep in core_dependencies_from_source]
 
     session.install(*dep_paths, "--no-deps", "--ignore-installed")
+    session.install("pytest-xdist")
     print(
         f"Installed {', '.join(core_dependencies_from_source)} locally from {deps_dir}"
     )
 
     session.run(
         "py.test",
+        "-n",
+        "auto",
         "tests/unit",
         env={
             "PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION": protobuf_implementation,

packages/google-cloud-spanner/setup.py

@@ -60,7 +60,17 @@
     "google-cloud-monitoring >= 2.16.0",
     "mmh3 >= 4.1.0",
 ]
-extras = {"libcst": "libcst >= 0.2.5"}
+extras = {
+    "libcst": "libcst >= 0.2.5",
+    "test": [
+        "pytest",
+        "mock",
+        "asyncmock",
+        "pytest-cov",
+        "pytest-asyncio",
+        "pytest-xdist",
+    ],
+}
 
 url = "https://github.com/googleapis/google-cloud-python/tree/main/packages/google-cloud-spanner"
 

packages/google-cloud-spanner/tests/unit/conftest.py

@@ -13,6 +13,20 @@
 # limitations under the License.
 
 import os
+import pytest
+from google.cloud.spanner_v1.metrics.spanner_metrics_tracer_factory import SpannerMetricsTracerFactory
 
 # Disable builtin metrics to avoid background thread noise and 401 errors in unit tests
 os.environ["SPANNER_DISABLE_BUILTIN_METRICS"] = "true"
+
+
+@pytest.fixture(autouse=True)
+def reset_metrics_singletons(monkeypatch):
+    # Reset singletons and env var before test to avoid state pollution
+    monkeypatch.setenv("SPANNER_DISABLE_BUILTIN_METRICS", "true")
+    SpannerMetricsTracerFactory._metrics_tracer_factory = None
+    SpannerMetricsTracerFactory._current_metrics_tracer_ctx.set(None)
+    yield
+    # Reset singletons after test to ensure no leakage
+    SpannerMetricsTracerFactory._metrics_tracer_factory = None
+    SpannerMetricsTracerFactory._current_metrics_tracer_ctx.set(None)

packages/google-cloud-spanner/tests/unit/spanner_dbapi/test_partition_helper.py

@@ -193,7 +193,7 @@ def collect_protobufs(val):
 
         registered_classes = set(partition_helper._PROTO_CLASS_MAP.values())
         for cls in discovered_protobuf_classes:
-            with self.subTest(cls=cls):
+            with self.subTest(cls_name=cls.__name__):
                 self.assertIn(
                     cls,
                     registered_classes,

packages/google-cloud-spanner/tests/unit/test__helpers.py

@@ -329,7 +329,7 @@ def test_w_numeric_precision_and_scale_valid(self):
             decimal.Decimal("1E-9"),
         ]
         for value in cases:
-            with self.subTest(value=value):
+            with self.subTest(value=str(value)):
                 value_pb = self._callFUT(value)
                 self.assertIsInstance(value_pb, Value)
                 self.assertEqual(value_pb.string_value, str(value))
@@ -371,7 +371,7 @@ def test_w_numeric_precision_and_scale_invalid(self):
         ]
 
         for value, err_msg in cases:
-            with self.subTest(value=value, err_msg=err_msg):
+            with self.subTest(value=str(value), err_msg=err_msg):
                 self.assertRaisesRegex(
                     ValueError,
                     err_msg,

packages/google-cloud-spanner/tests/unit/test_session.py

@@ -1716,7 +1716,9 @@ def unit_of_work(txn, *args, **kw):
 
         # retry once w/ timeout_secs=1
         def _time(_results=[1, 1.5]):
-            return _results.pop(0)
+            if len(_results) > 1:
+                return _results.pop(0)
+            return _results[0]
 
         with mock.patch("time.time", _time):
             with mock.patch("time.sleep") as sleep_mock:
@@ -1785,7 +1787,9 @@ def unit_of_work(txn, *args, **kw):
 
         # retry several times to check backoff
         def _time(_results=[1, 2, 4, 8]):
-            return _results.pop(0)
+            if len(_results) > 1:
+                return _results.pop(0)
+            return _results[0]
 
         with (
             mock.patch("time.time", _time),