First pass at version constraint solver.

utils/tests/pub/version_test.dart

Index: utils/tests/pub/version_test.dart
diff --git a/utils/tests/pub/version_test.dart b/utils/tests/pub/version_test.dart
index 2922a5bbe98871d00cde53f3d7390af00d0e0a55..8600a501746dfab3f0bbb5ab911eab8c5a8c8897 100644
--- a/utils/tests/pub/version_test.dart
+++ b/utils/tests/pub/version_test.dart
@@ -9,6 +9,14 @@
 #import('../../pub/version.dart');
 
 main() {
+  final v123 = new Version.parse('1.2.3');
+  final v114 = new Version.parse('1.1.4');
+  final v124 = new Version.parse('1.2.4');
+  final v200 = new Version.parse('2.0.0');
+  final v234 = new Version.parse('2.3.4');
+  final v250 = new Version.parse('2.5.0');
+  final v300 = new Version.parse('3.0.0');
+
   group('Version', () {
     test('none', () {
       expect(Version.none.toString(), equals('0.0.0'));
@@ -73,9 +81,27 @@ main() {
     });
 
     test('allows()', () {
-      expect(new Version.parse('1.2.3').allows(new Version.parse('1.2.3')));
-      expect(!new Version.parse('1.2.3').allows(new Version.parse('1.1.4')));
-      expect(!new Version.parse('1.2.3').allows(new Version.parse('1.2.4')));
+      expect(v123.allows(v123));
+      expect(!v123.allows(v114));
+      expect(!v123.allows(v124));
+    });
+
+    test('intersect()', () {
+      // Intersecting the same version returns the version.
+      expect(v123.intersect(v123), equals(v123));
+
+      // Intersecting a different version allows no versions.
+      expect(v123.intersect(v114).isEmpty);
+
+      // Intersecting a range returns the version if the range allows it.
+      expect(v123.intersect(new VersionRange(v114, v124)), equals(v123));
+
+      // Intersecting a range allows no versions if the range doesn't allow it.
+      expect(v114.intersect(new VersionRange(v123, v124)).isEmpty);
+    });
+
+    test('isEmpty', () {
+      expect(!v123.isEmpty);
     });
 
     test('parse()', () {
@@ -123,17 +149,14 @@ main() {
   group('VersionRange', () {
     group('constructor', () {
       test('takes a min and max', () {
-        var min = new Version.parse('1.2.3');
-        var max = new Version.parse('1.3.5');
-        var range = new VersionRange(min, max);
-        expect(range.min, equals(min));
-        expect(range.max, equals(max));
+        var range = new VersionRange(v123, v124);
+        expect(range.min, equals(v123));
+        expect(range.max, equals(v124));
       });
 
       test('allows omitting max', () {
-        var min = new Version.parse('1.2.3');
-        var range = new VersionRange(min);
-        expect(range.min, equals(min));
+        var range = new VersionRange(v123);
+        expect(range.min, equals(v123));
         expect(range.max, isNull);
       });
 
@@ -143,18 +166,43 @@ main() {
         expect(range.max, isNull);
       });
 
-      test('throws if min > max', () {
-        var min = new Version.parse('1.2.3');
-        var max = new Version.parse('1.0.0');
+      test('takes includeMin', () {
+        var range = new VersionRange(min: v123, includeMin: true);
+        expect(range.includeMin);
+      });
 
-        throwsIllegalArg(() => new VersionRange(min, max));
+      test('includeMin defaults to false if omitted', () {
+        var range = new VersionRange(min: v123);
+        expect(range.includeMin, isFalse);
+      });
+
+      test('takes includeMax', () {
+        var range = new VersionRange(max: v123, includeMax: true);
+        expect(range.includeMax);
+      });
+
+      test('includeMax defaults to false if omitted', () {
+        var range = new VersionRange(max: v123);
+        expect(range.includeMax, isFalse);
+      });
+
+      test('throws if min > max', () {
+        throwsIllegalArg(() => new VersionRange(v124, v123));
       });
     });
 
     group('allows()', () {
-      test('version must be min or greater', () {
-        var range = new VersionRange(
-            new Version.parse('1.2.3'), new Version.parse('2.3.4'));
+      test('version must be greater than min', () {
+        var range = new VersionRange(v123, v234);
+
+        expect(!range.allows(new Version.parse('1.2.2')));
+        expect(!range.allows(new Version.parse('1.2.3')));
+        expect(range.allows(new Version.parse('1.3.3')));
+        expect(range.allows(new Version.parse('2.3.3')));
+      });
+
+      test('version must be min or greater if includeMin', () {
+        var range = new VersionRange(v123, v234, includeMin: true);
 
         expect(!range.allows(new Version.parse('1.2.2')));
         expect(range.allows(new Version.parse('1.2.3')));
@@ -163,25 +211,32 @@ main() {
       });
 
       test('version must be less than max', () {
-        var range = new VersionRange(
-            new Version.parse('1.2.3'), new Version.parse('2.3.4'));
+        var range = new VersionRange(v123, v234);
 
         expect(range.allows(new Version.parse('2.3.3')));
         expect(!range.allows(new Version.parse('2.3.4')));
         expect(!range.allows(new Version.parse('2.4.3')));
       });
 
+      test('version must be max or less if includeMax', () {
+        var range = new VersionRange(v123, v234, includeMax: true);
+
+        expect(range.allows(new Version.parse('2.3.3')));
+        expect(range.allows(new Version.parse('2.3.4')));
+        expect(!range.allows(new Version.parse('2.4.3')));
+      });
+
       test('has no min if one was not set', () {
-        var range = new VersionRange(max: new Version.parse('1.2.3'));
+        var range = new VersionRange(max: v123);
 
         expect(range.allows(new Version.parse('0.0.0')));
         expect(!range.allows(new Version.parse('1.2.3')));
       });
 
       test('has no max if one was not set', () {
-        var range = new VersionRange(new Version.parse('1.2.3'));
+        var range = new VersionRange(v123);
 
-        expect(range.allows(new Version.parse('1.2.3')));
+        expect(!range.allows(new Version.parse('1.2.3')));
         expect(range.allows(new Version.parse('1.3.3')));
         expect(range.allows(new Version.parse('999.3.3')));
       });
@@ -193,9 +248,182 @@ main() {
         expect(range.allows(new Version.parse('999.99.9')));
       });
     });
+
+    group('intersect()', () {
+      test('two overlapping ranges', () {
+        var a = new VersionRange(v123, v250);
+        var b = new VersionRange(v200, v300);
+        var intersect = a.intersect(b);
+        expect(intersect.min, equals(v200));
+        expect(intersect.max, equals(v250));
+        expect(intersect.includeMin, isFalse);
+        expect(intersect.includeMax, isFalse);
+      });
+
+      test('a non-overlapping range allows no versions', () {
+        var a = new VersionRange(v114, v124);
+        var b = new VersionRange(v200, v250);
+        expect(a.intersect(b).isEmpty);
+      });
+
+      test('adjacent ranges allow no versions if exclusive', () {
+        var a = new VersionRange(v114, v124, includeMax: false);
+        var b = new VersionRange(v124, v200, includeMin: true);
+        expect(a.intersect(b).isEmpty);
+      });
+
+      test('adjacent ranges allow version if inclusive', () {
+        var a = new VersionRange(v114, v124, includeMax: true);
+        var b = new VersionRange(v124, v200, includeMin: true);
+        expect(a.intersect(b), equals(v124));
+      });
+
+      test('with an open range', () {
+        var open = new VersionRange();
+        var a = new VersionRange(v114, v124);
+        expect(open.intersect(open), equals(open));
+        expect(a.intersect(open), equals(a));
+      });
+
+      test('returns the version if the range allows it', () {
+        expect(new VersionRange(v114, v124).intersect(v123), equals(v123));
+        expect(new VersionRange(v123, v124).intersect(v114).isEmpty);
+      });
+    });
+
+    test('isEmpty', () {
+      expect(new VersionRange().isEmpty, isFalse);
+      expect(new VersionRange(v123, v124).isEmpty, isFalse);
+    });
+  });
+
+  group('VersionConstraint', () {
+    test('empty', () {
+      expect(new VersionConstraint.empty().isEmpty);
+    });
+
+    group('parse()', () {
+      test('parses an exact version', () {
+        var constraint = new VersionConstraint.parse('1.2.3-alpha');
+        expect(constraint is Version);
+        expect(constraint, equals(new Version(1, 2, 3, pre: 'alpha')));
+      });
+
+      test('parses "any"', () {
+        var constraint = new VersionConstraint.parse('any');
+        expect(constraint is VersionConstraint);
+        expect(constraint, allows([
+            new Version.parse('0.0.0'),
+            new Version.parse('1.2.3'),
+            new Version.parse('12345.678.90')]));
+      });
+
+      test('parses a ">" minimum version', () {
+        expect(new VersionConstraint.parse('>1.2.3'), allows([
+            new Version.parse('1.2.3+foo'),
+            new Version.parse('1.2.4')]));
+        expect(new VersionConstraint.parse('>1.2.3'), doesNotAllow([
+            new Version.parse('1.2.1'),
+            new Version.parse('1.2.3-build'),
+            new Version.parse('1.2.3')]));
+      });
+
+      test('parses a ">=" minimum version', () {
+        expect(new VersionConstraint.parse('>=1.2.3'), allows([
+            new Version.parse('1.2.3'),
+            new Version.parse('1.2.3+foo'),
+            new Version.parse('1.2.4')]));
+        expect(new VersionConstraint.parse('>=1.2.3'), doesNotAllow([
+            new Version.parse('1.2.1'),
+            new Version.parse('1.2.3-build')]));
+      });
+
+      test('parses a "<" maximum version', () {
+        expect(new VersionConstraint.parse('<1.2.3'), allows([
+            new Version.parse('1.2.1'),
+            new Version.parse('1.2.3-build')]));
+        expect(new VersionConstraint.parse('<1.2.3'), doesNotAllow([
+            new Version.parse('1.2.3'),
+            new Version.parse('1.2.3+foo'),
+            new Version.parse('1.2.4')]));
+      });
+
+      test('parses a "<=" maximum version', () {
+        expect(new VersionConstraint.parse('<=1.2.3'), allows([
+            new Version.parse('1.2.1'),
+            new Version.parse('1.2.3-build'),
+            new Version.parse('1.2.3')]));
+        expect(new VersionConstraint.parse('<=1.2.3'), doesNotAllow([
+            new Version.parse('1.2.3+foo'),
+            new Version.parse('1.2.4')]));
+      });
+
+      test('parses a series of space-separated constraints', () {
+        var constraint = new VersionConstraint.parse('>1.0.0 >=1.2.3 <1.3.0');
+        expect(constraint, allows([
+            new Version.parse('1.2.3'),
+            new Version.parse('1.2.5')]));
+        expect(constraint, doesNotAllow([
+            new Version.parse('1.2.3-pre'),
+            new Version.parse('1.3.0'),
+            new Version.parse('3.4.5')]));
+      });
+
+      test('throws FormatException on a bad string', () {
+        throwsBadFormat(() => new VersionConstraint.parse(''));
+        throwsBadFormat(() => new VersionConstraint.parse('   '));
+        throwsBadFormat(() => new VersionConstraint.parse('not a version'));
+      });
+    });
   });
 }
 
+class VersionConstraintMatcher implements Matcher {
+  final List<Version> _expected;
+  final bool _allow;
+
+  VersionConstraintMatcher(this._expected, this._allow);
+
+  bool matches(item) => (item is VersionConstraint) &&
+      _expected.every((version) => item.allows(version) == _allow);
+
+  Description describe(Description description) =>
+      description.add(' ${_allow ? "allows" : "does not allow"} versions');
+
+  Description describeMismatch(item, Description mismatchDescription) {
+    if (item is! VersionConstraint) {
+      mismatchDescription.add('was not a VersionConstraint');
+      return mismatchDescription;
+    }
+
+    bool 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;
+  }
+}
+
+Matcher allows(List<Version> versions) =>
+    new VersionConstraintMatcher(versions, true);
+
+Matcher doesNotAllow(List<Version> versions) =>
+    new VersionConstraintMatcher(versions, false);
+
 throwsIllegalArg(function) {
   expectThrow(function, (e) => e is IllegalArgumentException);
 }