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1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file | |
2 // for details. All rights reserved. Use of this source code is governed by a | |
3 // BSD-style license that can be found in the LICENSE file. | |
4 | |
5 // To decouple the reporting of errors, and allow for extensibility of | |
6 // matchers, we make use of some interfaces. | |
7 | |
8 /** | |
9 * The ErrorFormatter type is used for functions that | |
10 * can be used to build up error reports upon [expect] failures. | |
11 * There is one built-in implementation ([defaultErrorFormatter]) | |
12 * which is used by the default failure handler. If the failure handler | |
13 * is replaced it may be desirable to replace the [stringDescription] | |
14 * error formatter with another. | |
15 */ | |
16 | |
17 part of unittest; | |
18 | |
19 typedef String ErrorFormatter(actual, Matcher matcher, String reason, | |
20 MatchState matchState, bool verbose); | |
21 | |
22 /** | |
23 * Matchers build up their error messages by appending to | |
24 * Description objects. This interface is implemented by | |
25 * StringDescription. This interface is unlikely to need | |
26 * other implementations, but could be useful to replace in | |
27 * some cases - e.g. language conversion. | |
28 */ | |
29 abstract class Description { | |
30 /** Change the value of the description. */ | |
31 Description replace(String text); | |
32 | |
33 /** This is used to add arbitrary text to the description. */ | |
34 Description add(String text); | |
35 | |
36 /** This is used to add a meaningful description of a value. */ | |
37 Description addDescriptionOf(value); | |
38 | |
39 /** | |
40 * This is used to add a description of an [Iterable] [list], | |
41 * with appropriate [start] and [end] markers and inter-element [separator]. | |
42 */ | |
43 Description addAll(String start, String separator, String end, | |
44 Iterable list); | |
45 } | |
46 | |
47 /** | |
48 * [expect] Matchers must implement the Matcher class. | |
49 * The base Matcher class that implements this interface has | |
50 * a generic implementation of [describeMismatch] so this does | |
51 * not need to be provided unless a more clear description is | |
52 * required. The other two methods ([matches] and [describe]) | |
53 * must always be provided as they are highly matcher-specific. | |
54 */ | |
55 abstract class Matcher { | |
56 /** | |
57 * This does the matching of the actual vs expected values. | |
58 * [item] is the actual value. [matchState] can be supplied | |
59 * and may be used to add details about the mismatch that are too | |
60 * costly to determine in [describeMismatch]. | |
61 */ | |
62 bool matches(item, MatchState matchState); | |
63 | |
64 /** This builds a textual description of the matcher. */ | |
65 Description describe(Description description); | |
66 | |
67 /** | |
68 * This builds a textual description of a specific mismatch. [item] | |
69 * is the value that was tested by [matches]; [matchState] is | |
70 * the [MatchState] that was passed to and supplemented by [matches] | |
71 * with additional information about the mismact, and [mismatchDescription] | |
72 * is the [Description] that is being built to decribe the mismatch. | |
73 * A few matchers make use of the [verbose] flag to provide detailed | |
74 * information that is not typically included but can be of help in | |
75 * diagnosing failures, such as stack traces. | |
76 */ | |
77 Description describeMismatch(item, Description mismatchDescription, | |
78 MatchState matchState, bool verbose); | |
79 } | |
80 | |
81 /** | |
82 * Failed matches are reported using a default IFailureHandler. | |
83 * The default implementation simply throws ExpectExceptions; | |
84 * this can be replaced by some other implementation of | |
85 * IFailureHandler by calling configureExpectHandler. | |
86 */ | |
87 abstract class FailureHandler { | |
88 /** This handles failures given a textual decription */ | |
89 void fail(String reason); | |
90 | |
91 /** | |
92 * This handles failures given the actual [value], the [matcher] | |
93 * the [reason] (argument from [expect]), some additonal [matchState] | |
94 * generated by the [matcher], and a verbose flag which controls in | |
95 * some cases how much [matchState] information is used. It will use | |
96 * these to create a detailed error message (typically by calling | |
97 * an [ErrorFormatter]) and then call [fail] with this message. | |
98 */ | |
99 void failMatch(actual, Matcher matcher, String reason, | |
100 MatchState matchState, bool verbose); | |
101 } | |
102 | |
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