chore: test that ServiceUnavailable is retried (#970)

* chore: test that ServiceUnavailable is retried

* remove debug file

Author: tswast

tests/unit/test_client_v1.py tests/unit/test_read_client_v1.pytests/unit/test_client_v1.py renamed to tests/unit/test_read_client_v1.py

@@ -15,11 +15,12 @@
 import importlib
 from unittest import mock
 
+import google.api_core.exceptions
 from google.api_core.gapic_v1 import client_info
 from google.auth import credentials
 import pytest
 
-from google.cloud.bigquery_storage import types
+from google.cloud.bigquery_storage_v1 import types
 
 PROJECT = "my-project"
 SERVICE_ACCOUNT_PROJECT = "project-from-credentials"
@@ -29,20 +30,15 @@
 def mock_transport(monkeypatch):
     from google.cloud.bigquery_storage_v1.services.big_query_read import transports
 
-    fake_create_session_rpc = mock.Mock(name="create_read_session_rpc")
-    fake_read_rows_rpc = mock.Mock(name="read_rows_rpc")
-
     transport = mock.create_autospec(
         transports.grpc.BigQueryReadGrpcTransport, instance=True
     )
 
     transport.create_read_session = mock.Mock(name="fake_create_read_session")
     transport.read_rows = mock.Mock(name="fake_read_rows")
-
-    transport._wrapped_methods = {
-        transport.create_read_session: fake_create_session_rpc,
-        transport.read_rows: fake_read_rows_rpc,
-    }
+    transports.grpc.BigQueryReadGrpcTransport._prep_wrapped_messages(
+        transport, client_info.ClientInfo()
+    )
 
     # _credentials property for TPC support
     transport._credentials = ""
@@ -85,8 +81,11 @@ def __init__(self, *args, **kwargs):
 
 
 def test_create_read_session(mock_transport, client_under_test):
-    assert client_under_test._transport is mock_transport  # sanity check
+    # validate test assumptions
+    assert client_under_test._transport is mock_transport
 
+    rpc_callable = mock.Mock()
+    mock_transport._wrapped_methods[mock_transport.create_read_session] = rpc_callable
     table = "projects/{}/datasets/{}/tables/{}".format(
         "data-project-id", "dataset_id", "table_id"
     )
@@ -101,12 +100,47 @@ def test_create_read_session(mock_transport, client_under_test):
     expected_session_arg = types.CreateReadSessionRequest(
         parent="projects/other-project", read_session=read_session
     )
-    rpc_callable = mock_transport._wrapped_methods[mock_transport.create_read_session]
     rpc_callable.assert_called_once_with(
         expected_session_arg, metadata=mock.ANY, retry=mock.ANY, timeout=mock.ANY
     )
 
 
+def test_create_read_session_retries_serviceunavailable(
+    mock_transport, client_under_test
+):
+    """Regression test for https://github.com/googleapis/python-bigquery-storage/issues/969."""
+    # validate test assumptions
+    assert client_under_test._transport is mock_transport
+
+    mock_transport.create_read_session.side_effect = [
+        google.api_core.exceptions.ServiceUnavailable("connection reset"),
+        google.api_core.exceptions.ServiceUnavailable("connection reset"),
+        types.ReadSession(),
+    ]
+    table = "projects/{}/datasets/{}/tables/{}".format(
+        "data-project-id", "dataset_id", "table_id"
+    )
+    read_session = types.ReadSession()
+    read_session.table = table
+
+    # with pytest.raises(google.api_core.exceptions.ServiceUnavailable):
+    client_under_test.create_read_session(
+        parent="projects/other-project", read_session=read_session
+    )
+
+    expected_session_arg = types.CreateReadSessionRequest(
+        parent="projects/other-project", read_session=read_session
+    )
+    expected_call = mock.call(expected_session_arg, metadata=mock.ANY, timeout=mock.ANY)
+    mock_transport.create_read_session.assert_has_calls(
+        [
+            expected_call,
+            expected_call,
+            expected_call,
+        ]
+    )
+
+
 def test_read_rows(mock_transport, client_under_test):
     stream_name = "teststream"
     offset = 0