build: treat warnings as errors (#156)

Co-authored-by: ohmayr <omairnaveed@ymail.com>

Author: parthea

packages/google-cloud-testutils/pytest.ini

@@ -0,0 +1,4 @@
+[pytest]
+filterwarnings =
+    # treat all warnings as errors
+    error

packages/google-cloud-testutils/tests/unit/test_orchestrate.py

@@ -282,10 +282,11 @@ def run_in_test_thread():
 
 
 def test__get_syncpoints():  # pragma: SYNCPOINT test_get_syncpoints
-    lines = enumerate(open(__file__, "r"), start=1)
-    for expected_lineno, line in lines:  # pragma: NO BRANCH COVER
-        if "# pragma: SYNCPOINT test_get_syncpoints" in line:
-            break
+    with open(__file__, "r") as file:
+        lines = enumerate(file, start=1)
+        for expected_lineno, line in lines:  # pragma: NO BRANCH COVER
+            if "# pragma: SYNCPOINT test_get_syncpoints" in line:
+                break
 
     orchestrate._get_syncpoints(__file__)
     syncpoints = orchestrate._SYNCPOINTS[__file__]["test_get_syncpoints"]
@@ -327,10 +328,11 @@ def test__trace_this_source_file():
 
     @staticmethod
     def test__trace_reach_syncpoint():
-        lines = enumerate(open(__file__, "r"), start=1)
-        for syncpoint_lineno, line in lines:  # pragma: NO BRANCH COVER
-            if "# pragma: SYNCPOINT test_get_syncpoints" in line:
-                break
+        with open(__file__, "r") as file:
+            lines = enumerate(file, start=1)
+            for syncpoint_lineno, line in lines:  # pragma: NO BRANCH COVER
+                if "# pragma: SYNCPOINT test_get_syncpoints" in line:
+                    break
 
         orchestrate._SYNCPOINTS.clear()
         frame = mock.Mock(