How to test Futures in Dart that are not awaited?

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In order to test Futures in Dart that are not awaited, you can use the testWidgets function provided by the Flutter testing package. This function allows you to write Flutter widget tests that run in a widget tree, and you can use it to test Futures that are not awaited.

Here’s a simple example:

testWidgets('Test Future without await', (WidgetTester tester) async {
  // Create a Completer for the Future
  Completer<String> completer = Completer<String>();

  // Start the Future and do not await it
  Future<String> future = completer.future;

  // Add a listener to the Future to verify its value
  future.then((String value) {
    expect(value, equals('example'));
  });

  // Add a delay to simulate work being done asynchronously
  await Future.delayed(Duration(seconds: 1));

  // Complete the Future and verify that the listener was called
  completer.complete('example');
});

In this example, we create a Completer for the Future and start it without awaiting it. We then add a listener to the Future to verify its value, and add a delay to simulate work being done asynchronously. Finally, we complete the Future and verify that the listener was called.

Note that even though we did not await the Future, we still need to use the await keyword when delaying the test to ensure that the Future has time to complete before the test finishes.