Function assertCorrectKeyboardInteraction

src/material/stepper/stepper.spec.ts:1626–1724

Asserts that keyboard interaction works correctly.

(
  fixture: ComponentFixture<{stepper: MatStepper}>,
  stepHeaders: DebugElement[],
  orientation: StepperOrientation,
)

/** Asserts that keyboard interaction works correctly. */
function assertCorrectKeyboardInteraction(
  fixture: ComponentFixture<{stepper: MatStepper}>,
  stepHeaders: DebugElement[],
  orientation: StepperOrientation,
) {
  const stepper = fixture.componentInstance.stepper;
  const nextKey = orientation === 'vertical' ? DOWN_ARROW : RIGHT_ARROW;
  const prevKey = orientation === 'vertical' ? UP_ARROW : LEFT_ARROW;

  expect(stepper._getFocusIndex()).toBe(0);
  expect(stepper.selectedIndex).toBe(0);

  let stepHeaderEl = stepHeaders[0].nativeElement;
  dispatchKeyboardEvent(stepHeaderEl, 'keydown', nextKey);
  fixture.detectChanges();

  expect(stepper._getFocusIndex())
    .withContext('Expected index of focused step to increase by 1 after pressing the next key.')
    .toBe(1);
  expect(stepper.selectedIndex)
    .withContext('Expected index of selected step to remain unchanged after pressing the next key.')
    .toBe(0);

  stepHeaderEl = stepHeaders[1].nativeElement;
  dispatchKeyboardEvent(stepHeaderEl, 'keydown', ENTER);
  fixture.detectChanges();

  expect(stepper._getFocusIndex())
    .withContext('Expected index of focused step to remain unchanged after ENTER event.')
    .toBe(1);
  expect(stepper.selectedIndex)
    .withContext(
      'Expected index of selected step to change to index of focused step ' + 'after ENTER event.',
    )
    .toBe(1);

  stepHeaderEl = stepHeaders[1].nativeElement;
  dispatchKeyboardEvent(stepHeaderEl, 'keydown', prevKey);
  fixture.detectChanges();

  expect(stepper._getFocusIndex())
    .withContext(
      'Expected index of focused step to decrease by 1 after pressing the ' + 'previous key.',
    )
    .toBe(0);
  expect(stepper.selectedIndex)
    .withContext(
      'Expected index of selected step to remain unchanged after pressing the ' + 'previous key.',
    )
    .toBe(1);

  // When the focus is on the last step and right arrow key is pressed, the focus should cycle
  // through to the first step.
  (stepper as any)._keyManager.updateActiveItem(2);
  stepHeaderEl = stepHeaders[2].nativeElement;
  dispatchKeyboardEvent(stepHeaderEl, 'keydown', nextKey);
  fixture.detectChanges();