Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/matcher/src/iterable_matchers.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.
+
+library matcher.iterable_matchers;
+
+import 'core_matchers.dart';
+import 'description.dart';
+import 'interfaces.dart';
+import 'util.dart';
+
+/// Returns a matcher which matches [Iterable]s in which all elements
+/// match the given [matcher].
+Matcher everyElement(matcher) => new _EveryElement(wrapMatcher(matcher));
+
+class _EveryElement extends _IterableMatcher {
+  final Matcher _matcher;
+
+  _EveryElement(Matcher this._matcher);
+
+  bool matches(item, Map matchState) {
+    if (item is! Iterable) {
+      return false;
+    }
+    var i = 0;
+    for (var element in item) {
+      if (!_matcher.matches(element, matchState)) {
+        addStateInfo(matchState, {'index': i, 'element': element});
+        return false;
+      }
+      ++i;
+    }
+    return true;
+  }
+
+  Description describe(Description description) =>
+      description.add('every element(').addDescriptionOf(_matcher).add(')');
+
+  Description describeMismatch(item, Description mismatchDescription,
+                               Map matchState, bool verbose) {
+    if (matchState['index'] != null) {
+      var index = matchState['index'];
+      var element = matchState['element'];
+      mismatchDescription.add('has value ').addDescriptionOf(element).
+          add(' which ');
+      var subDescription = new StringDescription();
+      _matcher.describeMismatch(element, subDescription, matchState['state'],
+          verbose);
+      if (subDescription.length > 0) {
+        mismatchDescription.add(subDescription.toString());
+      } else {
+        mismatchDescription.add("doesn't match ");
+        _matcher.describe(mismatchDescription);
+      }
+      mismatchDescription.add(' at index $index');
+      return mismatchDescription;
+    }
+    return super.describeMismatch(item, mismatchDescription,
+          matchState, verbose);
+  }
+}
+
+/// Returns a matcher which matches [Iterable]s in which at least one
+/// element matches the given [matcher].
+Matcher anyElement(matcher) => new _AnyElement(wrapMatcher(matcher));
+
+class _AnyElement extends _IterableMatcher {
+  final Matcher _matcher;
+
+  _AnyElement(this._matcher);
+
+  bool matches(item, Map matchState) {
+    return item.any((e) => _matcher.matches(e, matchState));
+  }
+
+  Description describe(Description description) =>
+      description.add('some element ').addDescriptionOf(_matcher);
+}
+
+/// Returns a matcher which matches [Iterable]s that have the same
+/// length and the same elements as [expected], in the same order.
+///
+/// This is equivalent to [equals] but does not recurse.
+Matcher orderedEquals(Iterable expected) => new _OrderedEquals(expected);
+
+class _OrderedEquals extends Matcher {
+  final Iterable _expected;
+  Matcher _matcher;
+
+  _OrderedEquals(this._expected) {
+    _matcher = equals(_expected, 1);
+  }
+
+  bool matches(item, Map matchState) =>
+      (item is Iterable) && _matcher.matches(item, matchState);
+
+  Description describe(Description description) =>
+      description.add('equals ').addDescriptionOf(_expected).add(' ordered');
+
+  Description describeMismatch(item, Description mismatchDescription,
+                               Map matchState, bool verbose) {
+    if (item is !Iterable) {
+      return mismatchDescription.add('is not an Iterable');
+    } else {
+      return _matcher.describeMismatch(item, mismatchDescription,
+          matchState, verbose);
+    }
+  }
+}
+
+/// Returns a matcher which matches [Iterable]s that have the same length and
+/// the same elements as [expected], but not necessarily in the same order.
+///
+/// Note that this is O(n^2) so should only be used on small objects.
+Matcher unorderedEquals(Iterable expected) => new _UnorderedEquals(expected);
+
+class _UnorderedEquals extends _UnorderedMatches {
+  final List _expectedValues;
+
+  _UnorderedEquals(Iterable expected)
+      : super(expected.map(equals)),
+        _expectedValues = expected.toList();
+
+  Description describe(Description description) =>
+    description
+        .add('equals ')
+        .addDescriptionOf(_expectedValues)
+        .add(' unordered');
+}
+
+/// Iterable matchers match against [Iterable]s. We add this intermediate
+/// class to give better mismatch error messages than the base Matcher class.
+abstract class _IterableMatcher extends Matcher {
+  const _IterableMatcher();
+  Description describeMismatch(item, Description mismatchDescription,
+                               Map matchState, bool verbose) {
+    if (item is! Iterable) {
+      return mismatchDescription.
+          addDescriptionOf(item).
+          add(' not an Iterable');
+    } else {
+      return super.describeMismatch(item, mismatchDescription, matchState,
+          verbose);
+    }
+  }
+}
+
+/// Returns a matcher which matches [Iterable]s whose elements match the
+/// matchers in [expected], but not necessarily in the same order.
+///
+///  Note that this is `O(n^2)` and so should only be used on small objects.
+Matcher unorderedMatches(Iterable expected) => new _UnorderedMatches(expected);
+
+class _UnorderedMatches extends Matcher {
+  final List<Matcher> _expected;
+
+  _UnorderedMatches(Iterable expected)
+      : _expected = expected.map(wrapMatcher).toList();
+
+  String _test(item) {
+    if (item is! Iterable) return 'not iterable';
+    item = item.toList();
+
+    // Check the lengths are the same.
+    if (_expected.length > item.length) {
+      return 'has too few elements (${item.length} < ${_expected.length})';
+    } else if (_expected.length < item.length) {
+      return 'has too many elements (${item.length} > ${_expected.length})';
+    }
+
+    var matched = new List<bool>.filled(item.length, false);
+    var expectedPosition = 0;
+    for (var expectedMatcher in _expected) {
+      var actualPosition = 0;
+      var gotMatch = false;
+      for (var actualElement in item) {
+        if (!matched[actualPosition]) {
+          if (expectedMatcher.matches(actualElement, {})) {
+            matched[actualPosition] = gotMatch = true;
+            break;
+          }
+        }
+        ++actualPosition;
+      }
+
+      if (!gotMatch) {
+        return new StringDescription()
+            .add('has no match for ')
+            .addDescriptionOf(expectedMatcher)
+            .add(' at index ${expectedPosition}')
+            .toString();
+      }
+
+      ++expectedPosition;
+    }
+    return null;
+  }
+
+  bool matches(item, Map mismatchState) => _test(item) == null;
+
+  Description describe(Description description) =>
+    description
+      .add('matches ')
+      .addAll('[', ', ', ']', _expected)
+      .add(' unordered');
+
+  Description describeMismatch(item, Description mismatchDescription,
+                               Map matchState, bool verbose) =>
+      mismatchDescription.add(_test(item));
+}
+
+/// A pairwise matcher for [Iterable]s.
+///
+/// The [comparator] function, taking an expected and an actual argument, and
+/// returning whether they match, will be applied to each pair in order.
+/// [description] should be a meaningful name for the comparator.
+Matcher pairwiseCompare(Iterable expected, bool comparator(a, b),
+    String description) =>
+        new _PairwiseCompare(expected, comparator, description);
+
+typedef bool _Comparator(a, b);
+
+class _PairwiseCompare extends _IterableMatcher {
+  final Iterable _expected;
+  final _Comparator _comparator;
+  final String _description;
+
+  _PairwiseCompare(this._expected, this._comparator, this._description);
+
+  bool matches(item, Map matchState) {
+    if (item is! Iterable) return false;
+    if (item.length != _expected.length) return false;
+    var iterator = item.iterator;
+    var i = 0;
+    for (var e in _expected) {
+      iterator.moveNext();
+      if (!_comparator(e, iterator.current)) {
+        addStateInfo(matchState, {'index': i, 'expected': e,
+            'actual': iterator.current});
+        return false;
+      }
+      i++;
+    }
+    return true;
+  }
+
+  Description describe(Description description) =>
+      description.add('pairwise $_description ').addDescriptionOf(_expected);
+
+  Description describeMismatch(item, Description mismatchDescription,
+                               Map matchState, bool verbose) {
+    if (item is !Iterable) {
+      return mismatchDescription.add('is not an Iterable');
+    } else if (item.length != _expected.length) {
+      return mismatchDescription.
+          add('has length ${item.length} instead of ${_expected.length}');
+    } else {
+      return mismatchDescription.
+          add('has ').
+          addDescriptionOf(matchState["actual"]).
+          add(' which is not $_description ').
+          addDescriptionOf(matchState["expected"]).
+          add(' at index ${matchState["index"]}');
+    }
+  }
+}