public function testConfigureAuthentication()
{
$keyFilePath = __DIR__ . '/fixtures/json-key-fixture.json';
putenv("GOOGLE_APPLICATION_CREDENTIALS={$keyFilePath}");
// for application default credentials
$trait = new ClientTraitStub();
$conf = $trait->runConfigureAuthentication([]);
$this->assertEquals(json_decode(file_get_contents($keyFilePath), true), $conf['keyFile']);
$this->assertEquals('example_project', $trait->getProjectId());
}