Function testSingleColumnSortDirectionSequence

src/material/sort/sort.spec.ts:409–439

* Performs a sequence of sorting on a single column to see if the sort directions are * consistent with expectations. Detects any changes in the fixture to reflect any changes in * the inputs and resets the MatSort to remove any side effects from previous tests.

(
  fixture: ComponentFixture<SimpleMatSortApp | MatSortWithoutExplicitInputs>,
  expectedSequence: SortDirection[],
  id: SimpleMatSortAppColumnIds = 'defaultA',
)

 * the inputs and resets the MatSort to remove any side effects from previous tests.
 */
function testSingleColumnSortDirectionSequence(
  fixture: ComponentFixture<SimpleMatSortApp | MatSortWithoutExplicitInputs>,
  expectedSequence: SortDirection[],
  id: SimpleMatSortAppColumnIds = 'defaultA',
) {
  // Detect any changes that were made in preparation for this sort sequence
  fixture.detectChanges();

  // Reset the sort to make sure there are no side affects from previous tests
  const component = fixture.componentInstance;
  component.matSort.active = '';
  component.matSort.direction = '';

  // Run through the sequence to confirm the order
  const actualSequence = expectedSequence.map(() => {
    component.sort(id);

    // Check that the sort event's active sort is consistent with the MatSort
    expect(component.matSort.active).toBe(id);
    expect(component.latestSortEvent.active).toBe(id);

    // Check that the sort event's direction is consistent with the MatSort
    expect(component.matSort.direction).toBe(component.latestSortEvent.direction);
    return component.matSort.direction;
  });
  expect(actualSequence).toEqual(expectedSequence);

  // Expect that performing one more sort will loop it back to the beginning.
  component.sort(id);
  expect(component.matSort.direction).toBe(expectedSequence[0]);
}

/** Column IDs of the SimpleMatSortApp for typing of function params in the component (e.g. sort) */
type SimpleMatSortAppColumnIds = 'defaultA' | 'defaultB' | 'overrideStart' | 'overrideDisableClear';