matches method Null safety

  1. @override
bool matches(
  1. dynamic item,
  2. Map matchState

Does the matching of the actual vs expected values.

item is the actual value. matchState can be supplied and may be used to add details about the mismatch that are too costly to determine in describeMismatch.


bool matches(item, Map matchState) {
  final result = matchAsync(item);
      anyOf([equals(null), TypeMatcher<Future>(), TypeMatcher<String>()]),
      reason: 'matchAsync() may only return a String, a Future, or null.');

  if (result is Future) {
    final outstandingWork = TestHandle.current.markPending();
    result.then((realResult) {
      if (realResult != null) {
        fail(formatFailure(this, item, realResult as String));
  } else if (result is String) {
    matchState[this] = result;
    return false;

  return true;