Google\Cloud\Tests\Snippets\Vision\AnnotationTest::testError PHP Method

    public function testError()
    {
        $snippet = $this->snippetFromMethod(Annotation::class, 'error');
        $snippet->addLocal('annotation', new Annotation(['error' => []]));
        $res = $snippet->invoke('error');
        $this->assertTrue(is_array($res->returnVal()));
    }