Extract out a source_span package from source_maps.

pkg/source_span/test/span_test.dart

Index: pkg/source_span/test/span_test.dart
diff --git a/pkg/source_span/test/span_test.dart b/pkg/source_span/test/span_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..c62753b1a59d66b54c5901deb9cd5155559b068e
--- /dev/null
+++ b/pkg/source_span/test/span_test.dart
@@ -0,0 +1,256 @@
+// 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.
+
+import 'package:unittest/unittest.dart';
+import 'package:source_span/source_span.dart';
+import 'package:source_span/src/colors.dart' as colors;
+
+main() {
+  var span;
+  setUp(() {
+    span = new SourceSpan(
+        new SourceLocation(5, sourceUrl: "foo.dart"),
+        new SourceLocation(12, sourceUrl: "foo.dart"),
+        "foo bar");
+  });
+
+  group('errors', () {
+    group('for new SourceSpan()', () {
+      test('source URLs must match', () {
+        var start = new SourceLocation(0, sourceUrl: "foo.dart");
+        var end = new SourceLocation(1, sourceUrl: "bar.dart");
+        expect(() => new SourceSpan(start, end, "_"), throwsArgumentError);
+      });
+
+      test('end must come after start', () {
+        var start = new SourceLocation(1);
+        var end = new SourceLocation(0);
+        expect(() => new SourceSpan(start, end, "_"), throwsArgumentError);
+      });
+
+      test('text must be the right length', () {
+        var start = new SourceLocation(0);
+        var end = new SourceLocation(1);
+        expect(() => new SourceSpan(start, end, "abc"), throwsArgumentError);
+      });
+    });
+
+    group('for union()', () {
+      test('source URLs must match', () {
+        var other = new SourceSpan(
+            new SourceLocation(12, sourceUrl: "bar.dart"),
+            new SourceLocation(13, sourceUrl: "bar.dart"),
+            "_");
+
+        expect(() => span.union(other), throwsArgumentError);
+      });
+
+      test('spans may not be disjoint', () {
+        var other = new SourceSpan(
+            new SourceLocation(13, sourceUrl: 'foo.dart'),
+            new SourceLocation(14, sourceUrl: 'foo.dart'),
+            "_");
+
+        expect(() => span.union(other), throwsArgumentError);
+      });
+    });
+
+    test('for compareTo() source URLs must match', () {
+      var other = new SourceSpan(
+          new SourceLocation(12, sourceUrl: "bar.dart"),
+          new SourceLocation(13, sourceUrl: "bar.dart"),
+          "_");
+
+      expect(() => span.compareTo(other), throwsArgumentError);
+    });
+  });
+
+  test('fields work correctly', () {
+    expect(span.start, equals(new SourceLocation(5, sourceUrl: "foo.dart")));
+    expect(span.end, equals(new SourceLocation(12, sourceUrl: "foo.dart")));
+    expect(span.sourceUrl, equals(Uri.parse("foo.dart")));
+    expect(span.length, equals(7));
+  });
+
+  group("union()", () {
+    test("works with a preceding adjacent span", () {
+      var other = new SourceSpan(
+          new SourceLocation(0, sourceUrl: "foo.dart"),
+          new SourceLocation(5, sourceUrl: "foo.dart"),
+          "hey, ");
+
+      var result = span.union(other);
+      expect(result.start, equals(other.start));
+      expect(result.end, equals(span.end));
+      expect(result.text, equals("hey, foo bar"));
+    });
+
+    test("works with a preceding overlapping span", () {
+      var other = new SourceSpan(
+          new SourceLocation(0, sourceUrl: "foo.dart"),
+          new SourceLocation(8, sourceUrl: "foo.dart"),
+          "hey, foo");
+
+      var result = span.union(other);
+      expect(result.start, equals(other.start));
+      expect(result.end, equals(span.end));
+      expect(result.text, equals("hey, foo bar"));
+    });
+
+    test("works with a following adjacent span", () {
+      var other = new SourceSpan(
+          new SourceLocation(12, sourceUrl: "foo.dart"),
+          new SourceLocation(16, sourceUrl: "foo.dart"),
+          " baz");
+
+      var result = span.union(other);
+      expect(result.start, equals(span.start));
+      expect(result.end, equals(other.end));
+      expect(result.text, equals("foo bar baz"));
+    });
+
+    test("works with a following overlapping span", () {
+      var other = new SourceSpan(
+          new SourceLocation(9, sourceUrl: "foo.dart"),
+          new SourceLocation(16, sourceUrl: "foo.dart"),
+          "bar baz");
+
+      var result = span.union(other);
+      expect(result.start, equals(span.start));
+      expect(result.end, equals(other.end));
+      expect(result.text, equals("foo bar baz"));
+    });
+
+    test("works with an internal overlapping span", () {
+      var other = new SourceSpan(
+          new SourceLocation(7, sourceUrl: "foo.dart"),
+          new SourceLocation(10, sourceUrl: "foo.dart"),
+          "o b");
+
+      expect(span.union(other), equals(span));
+    });
+
+    test("works with an external overlapping span", () {
+      var other = new SourceSpan(
+          new SourceLocation(0, sourceUrl: "foo.dart"),
+          new SourceLocation(16, sourceUrl: "foo.dart"),
+          "hey, foo bar baz");
+
+      expect(span.union(other), equals(other));
+    });
+  });
+
+  group("message()", () {
+    test("prints the text being described", () {
+      expect(span.message("oh no"), equals("""
+line 1, column 6 of foo.dart: oh no
+foo bar
+^^^^^^^"""));
+    });
+
+    test("gracefully handles a missing source URL", () {
+      var span = new SourceSpan(
+          new SourceLocation(5), new SourceLocation(12), "foo bar");
+
+      expect(span.message("oh no"), equalsIgnoringWhitespace("""
+line 1, column 6: oh no
+foo bar
+^^^^^^^"""));
+    });
+
+    test("gracefully handles empty text", () {
+      var span = new SourceSpan(
+          new SourceLocation(5), new SourceLocation(5), "");
+
+      expect(span.message("oh no"),
+          equals("line 1, column 6: oh no"));
+    });
+
+    test("doesn't colorize if color is false", () {
+      expect(span.message("oh no", color: false), equals("""
+line 1, column 6 of foo.dart: oh no
+foo bar
+^^^^^^^"""));
+    });
+
+    test("colorizes if color is true", () {
+      expect(span.message("oh no", color: true),
+          equals("""
+line 1, column 6 of foo.dart: oh no
+${colors.RED}foo bar
+^^^^^^^${colors.NONE}"""));
+    });
+
+    test("uses the given color if it's passed", () {
+      expect(span.message("oh no", color: colors.YELLOW), equals("""
+line 1, column 6 of foo.dart: oh no
+${colors.YELLOW}foo bar
+^^^^^^^${colors.NONE}"""));
+    });
+  });
+
+  group("compareTo()", () {
+    test("sorts by start location first", () {
+      var other = new SourceSpan(
+          new SourceLocation(6, sourceUrl: "foo.dart"),
+          new SourceLocation(14, sourceUrl: "foo.dart"),
+          "oo bar b");
+
+      expect(span.compareTo(other), lessThan(0));
+      expect(other.compareTo(span), greaterThan(0));
+    });
+
+    test("sorts by length second", () {
+      var other = new SourceSpan(
+          new SourceLocation(5, sourceUrl: "foo.dart"),
+          new SourceLocation(14, sourceUrl: "foo.dart"),
+          "foo bar b");
+
+      expect(span.compareTo(other), lessThan(0));
+      expect(other.compareTo(span), greaterThan(0));
+    });
+
+    test("considers equal spans equal", () {
+      expect(span.compareTo(span), equals(0));
+    });
+  });
+
+  group("equality", () {
+    test("two spans with the same locations are equal", () {
+      var other = new SourceSpan(
+          new SourceLocation(5, sourceUrl: "foo.dart"),
+          new SourceLocation(12, sourceUrl: "foo.dart"),
+          "foo bar");
+
+      expect(span, equals(other));
+    });
+
+    test("a different start isn't equal", () {
+      var other = new SourceSpan(
+          new SourceLocation(0, sourceUrl: "foo.dart"),
+          new SourceLocation(12, sourceUrl: "foo.dart"),
+          "hey, foo bar");
+
+      expect(span, isNot(equals(other)));
+    });
+
+    test("a different end isn't equal", () {
+      var other = new SourceSpan(
+          new SourceLocation(5, sourceUrl: "foo.dart"),
+          new SourceLocation(16, sourceUrl: "foo.dart"),
+          "foo bar baz");
+
+      expect(span, isNot(equals(other)));
+    });
+
+    test("a different source URL isn't equal", () {
+      var other = new SourceSpan(
+          new SourceLocation(5, sourceUrl: "bar.dart"),
+          new SourceLocation(12, sourceUrl: "bar.dart"),
+          "foo bar");
+
+      expect(span, isNot(equals(other)));
+    });
+  });
+}