Google\Spreadsheet\DefaultServiceRequest::getHeaders PHP Method

    public function getHeaders()
    {
        return $this->headers;
    }

 public function testRemoveHeader()
 {
     $request = new DefaultServiceRequest("token");
     $headers = ["k" => "v"];
     $request->addHeader("k", "v");
     $this->assertEquals($headers, $request->getHeaders());
     $this->assertTrue($request->removeHeader("k") instanceof DefaultServiceRequest);
     $this->assertEquals([], $request->getHeaders());
 }