Testing your Cloud BigQueryRead application with googlemock

This document describes how to test your own Cloud BigQueryRead application using the Cloud BigQueryRead C++ client library, Google Test and the Google Test Mocking Framework.

Mocking a Successful BigQueryReadClient::GetServiceAccount() call

First include the headers for the Cloud BigQueryRead Client, the mocking class, and the Google Mock framework:

#include "google/cloud/bigquery/storage/v1/bigquery_read_client.h"
#include "google/cloud/bigquery/storage/v1/mocks/mock_bigquery_read_connection.h"
#include <gmock/gmock.h>

The example uses a number of aliases to save typing and improve readability:

using ::google::cloud::bigquery_storage_v1_mocks::MockBigQueryReadConnection;
namespace bigquery = ::google::cloud::bigquery_storage_v1;

Create a mocking object for google::cloud::bigquery_storage_v1::BigQueryReadConnection:

  auto mock = std::make_shared<MockBigQueryReadConnection>();

It is customary to first setup the expectations for your mock, and then write the rest of the code:

  EXPECT_CALL(*mock, CreateReadSession)
     
.WillOnce([&](google::cloud::bigquery::storage::v1::
                       
CreateReadSessionRequest const& request) {
        EXPECT_EQ
("test-project-name", request.parent());
        EXPECT_EQ
("test-table-name", request.read_session().table());
        google
::cloud::bigquery::storage::v1::ReadSession response;
        google
::cloud::bigquery::storage::v1::ReadStream stream;
        stream
.set_name("test-stream");
       
*response.add_streams() = stream;
       
return google::cloud::StatusOr<
            google
::cloud::bigquery::storage::v1::ReadSession>(response);
     
});

With the expectations in place, create a google::cloud::bigquery_storage_v1::BigQueryReadClient object:

  bigquery::BigQueryReadClient bigquery_client(mock);

And then make calls on the client as usual:

  google::cloud::bigquery::storage::v1::ReadSession read_session;
  read_session
.set_table("test-table-name");
 
int max_streams = 1;
 
auto session = bigquery_client.CreateReadSession("test-project-name",
                                                   read_session
, max_streams);

And then verify the results meet your expectations:

  EXPECT_TRUE(session.ok());
  EXPECT_EQ
("test-stream", session->streams(0).name());

Full Listing

Finally we present the full code for this example:


#include "google/cloud/bigquery/storage/v1/bigquery_read_client.h"
#include "google/cloud/bigquery/storage/v1/mocks/mock_bigquery_read_connection.h"
#include <gmock/gmock.h>

namespace {

using ::google::cloud::bigquery_storage_v1_mocks::MockBigQueryReadConnection;
namespace bigquery = ::google::cloud::bigquery_storage_v1;

TEST
(MockCreateReadSessionExample, CreateReadSession) {
 
auto mock = std::make_shared<MockBigQueryReadConnection>();

  EXPECT_CALL
(*mock, CreateReadSession)
     
.WillOnce([&](google::cloud::bigquery::storage::v1::
                       
CreateReadSessionRequest const& request) {
        EXPECT_EQ
("test-project-name", request.parent());
        EXPECT_EQ
("test-table-name", request.read_session().table());
        google
::cloud::bigquery::storage::v1::ReadSession response;
        google
::cloud::bigquery::storage::v1::ReadStream stream;
        stream
.set_name("test-stream");
       
*response.add_streams() = stream;
       
return google::cloud::StatusOr<
            google
::cloud::bigquery::storage::v1::ReadSession>(response);
     
});

  bigquery
::BigQueryReadClient bigquery_client(mock);

  google
::cloud::bigquery::storage::v1::ReadSession read_session;
  read_session
.set_table("test-table-name");
 
int max_streams = 1;
 
auto session = bigquery_client.CreateReadSession("test-project-name",
                                                   read_session
, max_streams);

  EXPECT_TRUE
(session.ok());
  EXPECT_EQ
("test-stream", session->streams(0).name());
}

}  // namespace