How to use the @aurelia/router.BrowserNavigator function in @aurelia/router

function createFixture() {
    const ctx = TestContext.createHTMLTestContext();
    const { lifecycle, scheduler, dom } = ctx;
    // const originalWnd = ctx.wnd;

    // const mockWnd = new MockWindow(originalWnd, originalWnd.history, originalWnd.location);
    // const addEventListener = createSpy(mockWnd, 'addEventListener');
    // const removeEventListener = createSpy(mockWnd, 'removeEventListener');

    // (DOM as Writable).window = mockWnd;

    const sut = new BrowserNavigator(scheduler, dom);
    const mockBrowserHistoryLocation = new MockBrowserHistoryLocation();
    mockBrowserHistoryLocation.changeCallback = sut.handlePopstate;
    sut.history = mockBrowserHistoryLocation as any;
    sut.location = mockBrowserHistoryLocation as any;

    function tearDown() {
      // (DOM as Writable).window = originalWnd;
    }

    callbackCount = 0;
    const callback = ((info) => {
      callbackCount++;
    });

    return { sut, tearDown, callback, lifecycle };
  }