SessionCacheContext example

$this->requestStack->push($this->request);

    $this->session = $this->getMockBuilder('\Symfony\Component\HttpFoundation\Session\SessionInterface')
      ->getMock();
  }

  /** * @covers ::getContext */
  public function testSameContextForSameSession() {
    $this->request->setSession($this->session);
    $cache_context = new SessionCacheContext($this->requestStack);

    $session_id = 'aSebeZ52bbM6SvADurQP89SFnEpxY6j8';
    $this->session->expects($this->exactly(2))
      ->method('getId')
      ->willReturn($session_id);

    $context1 = $cache_context->getContext();
    $context2 = $cache_context->getContext();
    $this->assertSame($context1, $context2);
    $this->assertStringNotContainsString($session_id, $context1, 'Session ID not contained in cache context');
  }