Harvest from pub. Mostly a straight copy, except:

test/utils.dart

+// Copyright (c) 2014, 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 pub_semver.test.utils;
+
+import 'package:unittest/unittest.dart';
+
+import 'package:pub_semver/pub_semver.dart';
+
+/// Some stock example versions to use in tests.
+final v114 = new Version.parse('1.1.4');
+final v123 = new Version.parse('1.2.3');
+final v124 = new Version.parse('1.2.4');
+final v130 = new Version.parse('1.3.0');
+final v140 = new Version.parse('1.4.0');
+final v200 = new Version.parse('2.0.0');
+final v201 = new Version.parse('2.0.1');
+final v234 = new Version.parse('2.3.4');
+final v250 = new Version.parse('2.5.0');
+final v300 = new Version.parse('3.0.0');
+
+/// A [Matcher] that tests if a [VersionConstraint] allows or does not allow a
+/// given list of [Version]s.
+class _VersionConstraintMatcher implements Matcher {
+  final List<Version> _expected;
+  final bool _allow;
+
+  _VersionConstraintMatcher(this._expected, this._allow);
+
+  bool matches(item, Map matchState) => (item is VersionConstraint) &&
+      _expected.every((version) => item.allows(version) == _allow);
+
+  Description describe(Description description) {
+    description.addAll(' ${_allow ? "allows" : "does not allow"} versions ',
+        ', ', '', _expected);
+    return description;
+  }
+
+  Description describeMismatch(item, Description mismatchDescription,
+      Map matchState, bool verbose) {
+    if (item is! VersionConstraint) {
+      mismatchDescription.add('was not a VersionConstraint');
+      return mismatchDescription;
+    }
+
+    var first = true;
+    for (var version in _expected) {
+      if (item.allows(version) != _allow) {
+        if (first) {
+          if (_allow) {
+            mismatchDescription.addDescriptionOf(item).add(' did not allow ');
+          } else {
+            mismatchDescription.addDescriptionOf(item).add(' allowed ');
+          }
+        } else {
+          mismatchDescription.add(' and ');
+        }
+        first = false;
+
+        mismatchDescription.add(version.toString());
+      }
+    }
+
+    return mismatchDescription;
+  }
+}
+
+/// Gets a [Matcher] that validates that a [VersionConstraint] allows all
+/// given versions.
+Matcher allows(Version v1, [Version v2, Version v3, Version v4,
+    Version v5, Version v6, Version v7, Version v8]) {
+  var versions = _makeVersionList(v1, v2, v3, v4, v5, v6, v7, v8);
+  return new _VersionConstraintMatcher(versions, true);
+}
+
+/// Gets a [Matcher] that validates that a [VersionConstraint] allows none of
+/// the given versions.
+Matcher doesNotAllow(Version v1, [Version v2, Version v3, Version v4,
+    Version v5, Version v6, Version v7, Version v8]) {
+  var versions = _makeVersionList(v1, v2, v3, v4, v5, v6, v7, v8);
+  return new _VersionConstraintMatcher(versions, false);
+}
+
+List<Version> _makeVersionList(Version v1, [Version v2, Version v3, Version v4,
+    Version v5, Version v6, Version v7, Version v8]) {
+  var versions = [v1];
+  if (v2 != null) versions.add(v2);
+  if (v3 != null) versions.add(v3);
+  if (v4 != null) versions.add(v4);
+  if (v5 != null) versions.add(v5);
+  if (v6 != null) versions.add(v6);
+  if (v7 != null) versions.add(v7);
+  if (v8 != null) versions.add(v8);
+  return versions;
+}