Monitoring: Fix environment variables for VPC tests. (googleapis#8302)

Author: busunkim96

monitoring/noxfile.py

@@ -122,12 +122,13 @@ def system(session):
     session.install("-e", ".")
 
     # Additional setup for VPCSC system tests
-    env = {
-        "PROJECT_ID": "secure-gcp-test-project-4",
-        "GOOGLE_CLOUD_TESTS_VPCSC_OUTSIDE_PERIMETER_PROJECT": os.environ.get(
-            "PROJECT_ID"
-        ),
-    }
+    if os.environ.get("GOOGLE_CLOUD_TESTS_IN_VPCSC") != "true":
+        # Unset PROJECT_ID, since VPCSC system tests expect this to be a project
+        # within the VPCSC perimeter.
+        env = {
+            "PROJECT_ID": "",
+            "GOOGLE_CLOUD_TESTS_VPCSC_OUTSIDE_PERIMETER_PROJECT": os.environ.get("PROJECT_ID"),
+        }
 
     # Run py.test against the system tests.
     if system_test_exists:

monitoring/tests/system/test_vpcsc.py

@@ -28,6 +28,8 @@
 from google.cloud.monitoring_v3 import enums
 
 PROJECT_INSIDE = os.environ.get("PROJECT_ID", None)
+if not PROJECT_INSIDE:
+    PROJECT_INSIDE = None
 PROJECT_OUTSIDE = os.environ.get(
     "GOOGLE_CLOUD_TESTS_VPCSC_OUTSIDE_PERIMETER_PROJECT", None
 )