| // 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. |
| |
| library matcher.expect; |
| |
| import 'core_matchers.dart'; |
| import 'description.dart'; |
| import 'interfaces.dart'; |
| |
| /// The objects thrown by the default failure handler. |
| class TestFailure extends Error { |
| final String message; |
| |
| TestFailure(this.message); |
| |
| String toString() => message; |
| } |
| |
| /// Useful utility for nesting match states. |
| |
| void addStateInfo(Map matchState, Map values) { |
| var innerState = new Map.from(matchState); |
| matchState.clear(); |
| matchState['state'] = innerState; |
| matchState.addAll(values); |
| } |
| |
| /// Some matchers, like those for Futures and exception testing, |
| /// can fail in asynchronous sections, and throw exceptions. |
| /// A user of this library will typically want to catch and handle |
| /// such exceptions. The [wrapAsync] property is a function that |
| /// can wrap callbacks used by these Matchers so that they can be |
| /// used safely. For example, the unittest library will set this |
| /// to be `expectAsync`. By default this is an identity function. |
| Function wrapAsync = (Function f, [id]) => f; |
| |
| /// This is the main assertion function. It asserts that [actual] |
| /// matches the [matcher]. [reason] is optional and is typically not |
| /// supplied, as a reason is generated from the matcher; if [reason] |
| /// is included it is appended to the reason generated by the matcher. |
| /// |
| /// [matcher] can be a value in which case it will be wrapped in an |
| /// [equals] matcher. |
| /// |
| /// If the assertion fails, then the default behavior is to throw a |
| /// [TestFailure], but this behavior can be changed by calling |
| /// [configureExpectFailureHandler] and providing an alternative handler that |
| /// implements the [IFailureHandler] interface. It is also possible to |
| /// pass a [failureHandler] to [expect] as a final parameter for fine- |
| /// grained control. |
| /// |
| /// In some cases extra diagnostic info can be produced on failure (for |
| /// example, stack traces on mismatched exceptions). To enable these, |
| /// [verbose] should be specified as true; |
| void expect(actual, matcher, {String reason, FailureHandler failureHandler, |
| bool verbose : false}) { |
| matcher = wrapMatcher(matcher); |
| bool doesMatch; |
| var matchState = {}; |
| try { |
| doesMatch = matcher.matches(actual, matchState); |
| } catch (e, trace) { |
| doesMatch = false; |
| if (reason == null) { |
| reason = '${(e is String) ? e : e.toString()} at $trace'; |
| } |
| } |
| if (!doesMatch) { |
| if (failureHandler == null) { |
| failureHandler = getOrCreateExpectFailureHandler(); |
| } |
| failureHandler.failMatch(actual, matcher, reason, matchState, verbose); |
| } |
| } |
| |
| void fail(String message, {FailureHandler failureHandler}) { |
| if (failureHandler == null) { |
| failureHandler = getOrCreateExpectFailureHandler(); |
| } |
| failureHandler.fail(message); |
| } |
| |
| /// Takes an argument and returns an equivalent matcher. |
| /// If the argument is already a matcher this does nothing, |
| /// else if the argument is a function, it generates a predicate |
| /// function matcher, else it generates an equals matcher. |
| Matcher wrapMatcher(x) { |
| if (x is Matcher) { |
| return x; |
| } else if (x is Function) { |
| return predicate(x); |
| } else { |
| return equals(x); |
| } |
| } |
| |
| // The handler for failed asserts. |
| FailureHandler _assertFailureHandler = null; |
| |
| // The default failure handler that throws [TestFailure]s. |
| class DefaultFailureHandler implements FailureHandler { |
| DefaultFailureHandler() { |
| if (_assertErrorFormatter == null) { |
| _assertErrorFormatter = _defaultErrorFormatter; |
| } |
| } |
| void fail(String reason) { |
| throw new TestFailure(reason); |
| } |
| void failMatch(actual, Matcher matcher, String reason, |
| Map matchState, bool verbose) { |
| fail(_assertErrorFormatter(actual, matcher, reason, matchState, verbose)); |
| } |
| } |
| |
| /// Changes or resets to the default the failure handler for expect() |
| /// [handler] is a reference to the new handler; if this is omitted |
| /// or null then the failure handler is reset to the default, which |
| /// throws [TestFailure]s on [expect] assertion failures. |
| void configureExpectFailureHandler([FailureHandler handler = null]) { |
| if (handler == null) { |
| handler = new DefaultFailureHandler(); |
| } |
| _assertFailureHandler = handler; |
| } |
| |
| FailureHandler getOrCreateExpectFailureHandler() { |
| if (_assertFailureHandler == null) { |
| configureExpectFailureHandler(); |
| } |
| return _assertFailureHandler; |
| } |
| |
| // The error message formatter for failed asserts. |
| ErrorFormatter _assertErrorFormatter = null; |
| |
| // The default error formatter implementation. |
| String _defaultErrorFormatter(actual, Matcher matcher, String reason, |
| Map matchState, bool verbose) { |
| var description = new StringDescription(); |
| description.add('Expected: ').addDescriptionOf(matcher).add('\n'); |
| description.add(' Actual: ').addDescriptionOf(actual).add('\n'); |
| |
| var mismatchDescription = new StringDescription(); |
| matcher.describeMismatch(actual, mismatchDescription, matchState, verbose); |
| |
| if (mismatchDescription.length > 0) { |
| description.add(' Which: ${mismatchDescription}\n'); |
| } |
| if (reason != null) { |
| description.add(reason).add('\n'); |
| } |
| return description.toString(); |
| } |
| |
| /// Changes or resets to default the failure message formatter for expect(). |
| /// [formatter] is a reference to the new formatter; if this is omitted or |
| /// null then the failure formatter is reset to the default. The new |
| /// formatter is returned; this allows custom expect handlers to easily |
| /// get a reference to the default formatter. |
| ErrorFormatter configureExpectFormatter([ErrorFormatter formatter = null]) { |
| if (formatter == null) { |
| formatter = _defaultErrorFormatter; |
| } |
| return _assertErrorFormatter = formatter; |
| } |