Google\Cloud\Tests\Snippets\PubSub\MessageTest::testAttribute PHP Method

    public function testAttribute()
    {
        $snippet = $this->snippetFromMethod(Message::class, 'attribute');
        $snippet->addLocal('message', $this->message);
        $res = $snippet->invoke();
        $this->assertEquals($this->msg['attributes']['browser-name'], $res->output());
    }