function DisplayManagerTest::testSimpleMockDisplayManager

Test for DisplayManager's DisplayableItemInterface handling.

This method sets up a mock DisplayableItemInterface object and then feeds it to a DisplayManager object to test the behavior of DisplayManager.

See the inline comments for a thorough walk-through.

File

modules/testing_example/tests/src/Unit/DisplayManagerTest.php, line 28

Class

DisplayManagerTest

DisplayManager unit test with doubles.

Namespace

Code

public function testSimpleMockDisplayManager() {
  // Setting up:
  // Get a mock object belonging to our desired interface.
  // Note that we have to fully qualify the domain name
  // for PHPUnit's benefit.
  $mock = $this->createMock(DisplayInfoInterface::class);
  // Here we're illustrating that the mock object belongs to
  // our interface.
  $this->assertTrue($mock instanceof DisplayInfoInterface);
  // 'Program' our mock object to return a value for getDisplayName().
  // expects($this->any()) tells the mock to return this value any time
  // the method is called.
  $mock->expects($this->any())
    ->method('getDisplayName')
    ->willReturn('the display name');
  // Create a DisplayManager, the class we're actually testing here.
  $dm = new DisplayManager();
  // Give it the mocked info object.
  $dm->addDisplayableItem($mock);
  // Assert that our DisplayManager has exactly one display object (our mock).
  $this->assertEquals(1, $dm->countDisplayableItems());
  // Assert that the DisplayManager can find our mocked info object.
  $this->assertSame($mock, $dm->item('the display name'));
  // Assert that the DisplayManager can't find an info object
  // that it shouldn't have.
  $this->assertNull($dm->item('nonexistent'));
}