gistfile1.txt

func testTableViewDataSourceIsKittenDataSource() {
    guard let controller = UIStoryboard(name: "Main", bundle: Bundle(for: ViewController.self)).instantiateInitialViewController() as? ViewController else {
        return XCTFail("Could not instantiate ViewController from main storyboard")
    }

    controller.loadViewIfNeeded()

    XCTAssertTrue(controller.tableView.dataSource is KittenDataSource,
                  "TableView's data source should be a KittenDataSource")
}