lib/goog/labs/testing/assertthat.js

1// Copyright 2012 The Closure Library Authors. All Rights Reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//      http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS-IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15/**
16 * @fileoverview Provides main functionality of assertThat. assertThat calls the
17 * matcher's matches method to test if a matcher matches assertThat's arguments.
18 */
19
20
21goog.provide('goog.labs.testing.MatcherError');
22goog.provide('goog.labs.testing.assertThat');
23
24goog.require('goog.asserts');
25goog.require('goog.debug.Error');
26goog.require('goog.labs.testing.Matcher');
27
28
29/**
30 * Asserts that the actual value evaluated by the matcher is true.
31 *
32 * @param {*} actual The object to assert by the matcher.
33 * @param {!goog.labs.testing.Matcher} matcher A matcher to verify values.
34 * @param {string=} opt_reason Description of what is asserted.
35 *
36 */
37goog.labs.testing.assertThat = function(actual, matcher, opt_reason) {
38  if (!matcher.matches(actual)) {
39    // Prefix the error description with a reason from the assert ?
40    var prefix = opt_reason ? opt_reason + ': ' : '';
41    var desc = prefix + matcher.describe(actual);
42
43    // some sort of failure here
44    throw new goog.labs.testing.MatcherError(desc);
45  }
46};
47
48
49
50/**
51 * Error thrown when a Matcher fails to match the input value.
52 * @param {string=} opt_message The error message.
53 * @constructor
54 * @extends {goog.debug.Error}
55 */
56goog.labs.testing.MatcherError = function(opt_message) {
57  goog.base(this, opt_message);
58};
59goog.inherits(goog.labs.testing.MatcherError, goog.debug.Error);