Improved error messages from unittest.

pkg/unittest/lib/src/interfaces.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.
 
 part of matcher;
 
 // To decouple the reporting of errors, and allow for extensibility of
 // matchers, we make use of some interfaces.
 
 /**
  * The ErrorFormatter type is used for functions that
  * can be used to build up error reports upon [expect] failures.
  * There is one built-in implementation ([defaultErrorFormatter])
  * which is used by the default failure handler. If the failure handler
  * is replaced it may be desirable to replace the [stringDescription]
  * error formatter with another.
  */
 typedef String ErrorFormatter(actual, Matcher matcher, String reason,
-    MatchState matchState, bool verbose);
+    Map matchState, bool verbose);
 
 /**
  * Matchers build up their error messages by appending to
  * Description objects. This interface is implemented by
  * StringDescription. This interface is unlikely to need
  * other implementations, but could be useful to replace in
  * some cases - e.g. language conversion.
  */
 abstract class Description {
   /** Change the value of the description. */
@@ skipping 21 matching lines @@
  * required. The other two methods ([matches] and [describe])
  * must always be provided as they are highly matcher-specific.
  */
 abstract class Matcher {
   /**
    * This 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, MatchState matchState);
+  bool matches(item, Map matchState);
 
   /** This builds a textual description of the matcher. */
   Description describe(Description description);
 
   /**
    * This builds a textual description of a specific mismatch. [item]
    * is the value that was tested by [matches]; [matchState] is
-   * the [MatchState] that was passed to and supplemented by [matches]
+   * the [Map] that was passed to and supplemented by [matches]
    * with additional information about the mismact, and [mismatchDescription]
    * is the [Description] that is being built to decribe the mismatch.
    * A few matchers make use of the [verbose] flag to provide detailed
    * information that is not typically included but can be of help in
    * diagnosing failures, such as stack traces.
    */
   Description describeMismatch(item, Description mismatchDescription,
-      MatchState matchState, bool verbose);
+      Map matchState, bool verbose);
 }
 
 /**
  * Failed matches are reported using a default IFailureHandler.
  * The default implementation simply throws [TestFailure]s;
  * this can be replaced by some other implementation of
  * IFailureHandler by calling configureExpectHandler.
  */
 abstract class FailureHandler {
   /** This handles failures given a textual decription */
   void fail(String reason);
 
   /**
    * This handles failures given the actual [value], the [matcher]
    * the [reason] (argument from [expect]), some additonal [matchState]
    * generated by the [matcher], and a verbose flag which controls in
    * some cases how much [matchState] information is used. It will use
    * these to create a detailed error message (typically by calling
    * an [ErrorFormatter]) and then call [fail] with this message.
    */
   void failMatch(actual, Matcher matcher, String reason,
-                 MatchState matchState, bool verbose);
+                 Map matchState, bool verbose);
 }