Add in test cases for gcompute_client_test.py.

Bug: 145376709
Test: ./run_test.sh && atest acloud_test
Change-Id: I48a44f4aa1dcbedb703916912494606ac55bb6a4
diff --git a/internal/lib/gcompute_client_test.py b/internal/lib/gcompute_client_test.py
index d341797..4571f11 100644
--- a/internal/lib/gcompute_client_test.py
+++ b/internal/lib/gcompute_client_test.py
@@ -1443,6 +1443,24 @@
         self.assertEqual(1, sentinel.hitFingerPrintConflict.call_count)
         self.assertEqual("Passed", result)
 
+    def testCheckAccess(self):
+        """Test CheckAccess."""
+        # Checking non-403 should raise error
+        error = errors.HttpError(503, "fake retriable error.")
+        self.Patch(
+            gcompute_client.ComputeClient, "Execute",
+            side_effect=error)
+
+        with self.assertRaises(errors.HttpError):
+            self.compute_client.CheckAccess()
+
+        # Checking 403 should return False
+        error = errors.HttpError(403, "fake retriable error.")
+        self.Patch(
+            gcompute_client.ComputeClient, "Execute",
+            side_effect=error)
+        self.assertFalse(self.compute_client.CheckAccess())
+
 
 if __name__ == "__main__":
     unittest.main()