pkgs/matcher/test/custom_matcher_test.dart

// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'package:matcher/matcher.dart';
import 'package:test/test.dart' show test;

import 'test_utils.dart';

class _BadCustomMatcher extends CustomMatcher {
  _BadCustomMatcher() : super('feature', 'description', {1: 'a'});
  @override
  Object? featureValueOf(dynamic actual) => throw Exception('bang');
}

class _HasPrice extends CustomMatcher {
  _HasPrice(Object? matcher)
    : super('Widget with a price that is', 'price', matcher);
  @override
  Object? featureValueOf(Object? actual) => (actual as Widget).price;
}

void main() {
  test('Feature Matcher', () {
    var w = Widget();
    w.price = 10;
    shouldPass(w, _HasPrice(10));
    shouldPass(w, _HasPrice(greaterThan(0)));
    shouldFail(
      w,
      _HasPrice(greaterThan(10)),
      'Expected: Widget with a price that is a value greater than <10> '
      "Actual: <Instance of 'Widget'> "
      'Which: has price with value <10> which is not '
      'a value greater than <10>',
    );
  });

  test('Custom Matcher Exception', () {
    shouldFail(
      'a',
      _BadCustomMatcher(),
      allOf([
        contains("Expected: feature {1: 'a'} "),
        contains("Actual: 'a' "),
        contains("Which: threw 'Exception: bang' "),
      ]),
    );
  });
}