public function testImmutability()
 {
     $pullRequests = new PullRequests();
     $pullRequest = PullRequest::fromArray(['title' => 'a', 'repositoryName' => 'foo/bar', 'url' => 'http://www.example.com/', 'loneliness' => 42]);
     $newPullRequests = $pullRequests->add($pullRequest);
     $anotherPullRequests = $pullRequests->add($pullRequest);
     $this->assertNotSame($pullRequest, $newPullRequests);
     $this->assertNotSame($pullRequest, $anotherPullRequests);
     $this->assertNotSame($newPullRequests, $anotherPullRequests);
     $this->assertEquals($newPullRequests, $anotherPullRequests);
 }
 /**
  * @param PullRequest $pullRequest
  *
  * @return PullRequests
  */
 public function add(PullRequest $pullRequest)
 {
     $this->pullRequests = $this->pullRequests->add($pullRequest);
 }