chore: detect samples tests in nested directories (#146)

Source-Link: googleapis/synthtool@50db768
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-python:latest@sha256:e09366bdf0fd9c8976592988390b24d53583dd9f002d476934da43725adbb978

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: gcf-owl-bot[bot]

.github/.OwlBot.lock.yaml

@@ -13,4 +13,4 @@
 # limitations under the License.
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-python:latest
-  digest: sha256:993a058718e84a82fda04c3177e58f0a43281a996c7c395e0a56ccc4d6d210d7
+  digest: sha256:e09366bdf0fd9c8976592988390b24d53583dd9f002d476934da43725adbb978

samples/snippets/noxfile.py

@@ -208,8 +208,10 @@ def _session_tests(
     session: nox.sessions.Session, post_install: Callable = None
 ) -> None:
     # check for presence of tests
-    test_list = glob.glob("*_test.py") + glob.glob("test_*.py")
-    test_list.extend(glob.glob("tests"))
+    test_list = glob.glob("**/*_test.py", recursive=True) + glob.glob(
+        "**/test_*.py", recursive=True
+    )
+    test_list.extend(glob.glob("**/tests", recursive=True))
 
     if len(test_list) == 0:
         print("No tests found, skipping directory.")