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petitparser/lib/test.dart

-/**
- * This package contains matches to write tests for parsers.
- *
- * Examples:
- *
- *     var json = new JsonParser();
- *
- *     // verifies that the input gets parsed and all input is consumed
- *     expect('{"a": 1}', accepts(new JsonParser()));
- *
- *     // verifies that the input gets parsed to a dictionary and that all input is consumed
- *     expect('{"a": 1}', parses(new JsonParser(), {'a': 1}));
- */
-
-library test_util;
-
-import 'package:matcher/matcher.dart';
-import 'package:petitparser/petitparser.dart' hide predicate;
-
-/**
- * Returns a matcher that succeeds if the [parser] accepts the input.
- */
-Matcher accept(Parser parser) {
-  return parse(parser, predicate((value) => true, 'input'));
-}
-
-/**
- * Returns a matcher that succeeds if the [parser] succeeds and accepts the provided [matcher].
- */
-Matcher parse(Parser parser, matcher, [int position = -1]) {
-  return new _Parse(parser, wrapMatcher(matcher), position);
-}
-
-class _Parse extends Matcher {
-
-  final Parser parser;
-  final Matcher matcher;
-  final int position;
-
-  _Parse(this.parser, this.matcher, this.position);
-
-  @override
-  bool matches(item, Map matchState) {
-    Result result = parser.parse(item);
-    if (result.isFailure) {
-      addStateInfo(matchState, {'reason': 'failure', 'result': result});
-      return false;
-    }
-    if (!matcher.matches(result.value, matchState)) {
-      addStateInfo(matchState, {'reason': 'matcher', 'result': result});
-      return false;
-    }
-    if (position >= 0 && position != result.value) {
-      addStateInfo(matchState, {'reason': 'position', 'result': result});
-      return false;
-    }
-    return true;
-  }
-
-  @override
-  Description describe(Description description) {
-    return description.add('"$parser" accepts ').addDescriptionOf(matcher);
-  }
-
-  @override
-  Description describeMismatch(item, Description description, Map matchState, bool verbose) {
-    description.add('"$parser" produces "${matchState['result']}"');
-    switch (matchState['reason']) {
-      case 'failure':
-        description.add(' which is not accepted');
-        return description;
-      case 'matcher':
-        description.add(' which parse result ');
-        var subDescription = new StringDescription();
-        matcher.describeMismatch(matchState['result'].value, subDescription,
-            matchState['state'], verbose);
-        if (subDescription.length > 0) {
-          description.add(subDescription.toString());
-        } else {
-          description.add('doesn\'t match');
-          matcher.describe(description);
-        }
-        return description;
-      case 'position':
-        description
-            .add(' that consumes input to ')
-            .add(matchState['result'].position.toString())
-            .add(' instead of ')
-            .add(position.toString());
-        return description;
-    }
-    throw new Exception('Internal matcher error');
-  }
-}