Introduce span with line context

test/span_test.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.
 
 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");
+    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 new SourceSpanWithContext()', () {
+      test('context must contain text', () {
+        var start = new SourceLocation(2);
+        var end = new SourceLocation(5);
+        expect(() => new SourceSpanWithContext(start, end, "abc", "--axc--"),
+            throwsArgumentError);
+      });
+
+      test('text starts at start.column in context', () {
+        var start = new SourceLocation(3);
+        var end = new SourceLocation(5);
+        expect(() => new SourceSpanWithContext(start, end, "abc", "--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"),
-            "_");
+            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'),
-            "_");
+            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"),
-          "_");
+      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 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 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 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 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");
+      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");
+      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), "");
+      var span =
+          new SourceSpan(new SourceLocation(5), new SourceLocation(5), "");
 
-      expect(span.message("oh no"),
-          equals("line 1, column 6: oh no"));
+      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("""
+      expect(span.message("oh no", color: true), equals("""
 line 1, column 6 of foo.dart: oh no
-${colors.RED}foo bar
-^^^^^^^${colors.NONE}"""));
+${colors.RED}foo bar${colors.NONE}
+${colors.RED}^^^^^^^${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}"""));
+${colors.YELLOW}foo bar${colors.NONE}
+${colors.YELLOW}^^^^^^^${colors.NONE}"""));
+    });
+  });
+
+  group("message() with context", () {
+    var spanWithContext;
+    setUp(() {
+      spanWithContext = new SourceSpanWithContext(
+          new SourceLocation(5, sourceUrl: "foo.dart"),
+          new SourceLocation(12, sourceUrl: "foo.dart"), "foo bar",
+          "-----foo bar-----");
+    });
+
+    test("underlines under the right column", () {
+      expect(spanWithContext.message("oh no", color: colors.YELLOW), equals("""
+line 1, column 6 of foo.dart: oh no
+-----${colors.YELLOW}foo bar${colors.NONE}-----
+     ${colors.YELLOW}^^^^^^^${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");
+      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");
+      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");
+      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");
+      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");
+      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");
+      var other = new SourceSpan(new SourceLocation(5, sourceUrl: "bar.dart"),
+          new SourceLocation(12, sourceUrl: "bar.dart"), "foo bar");
 
       expect(span, isNot(equals(other)));
     });
   });
 }