Google\Spreadsheet\DefaultServiceRequest::setUserAgent PHP Method

    public function setUserAgent($userAgent)
    {
        $this->userAgent = $userAgent;
        return $this;
    }

 public function testSetUserAgent()
 {
     $request = new DefaultServiceRequest("token");
     $this->assertTrue($request->setUserAgent("my user agent") instanceof DefaultServiceRequest);
     $this->assertEquals("my user agent", $request->getUserAgent());
 }