Make observable transform a barback transform.

pkg/source_maps/test/refactor_test.dart

Index: pkg/source_maps/test/refactor_test.dart
diff --git a/pkg/source_maps/test/refactor_test.dart b/pkg/source_maps/test/refactor_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..c153d904389d94fab0ff5f8b7233377118f03bd5
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+++ b/pkg/source_maps/test/refactor_test.dart
@@ -0,0 +1,96 @@
+// Copyright (c) 2013, 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 polymer.test.refactor_test;
+
+import 'package:unittest/unittest.dart';
+import 'package:source_maps/refactor.dart';
+import 'package:source_maps/span.dart';
+import 'package:source_maps/parser.dart' show parse, Mapping;
+
+main() {
+  group('conflict detection', () {
+    var original = "0123456789abcdefghij";
+    var file = new SourceFile.text('', original);
+
+    test('no conflict, in order', () {
+      var txn = new TextEditTransaction(original, file);
+      txn.edit(2, 4, '.');
+      txn.edit(5, 5, '|');
+      txn.edit(6, 6, '-');
+      txn.edit(6, 7, '_');
+      expect((txn.commit()..build('')).text, "01.4|5-_789abcdefghij");
+    });
+
+    test('no conflict, out of order', () {
+      var txn = new TextEditTransaction(original, file);
+      txn.edit(2, 4, '.');
+      txn.edit(5, 5, '|');
+
+      // Regresion test for issue #404: there is no conflict/overlap for edits
+      // that don't remove any of the original code.
+      txn.edit(6, 7, '_');
+      txn.edit(6, 6, '-');
+      expect((txn.commit()..build('')).text, "01.4|5-_789abcdefghij");
+
+    });
+
+    test('conflict', () {
+      var txn = new TextEditTransaction(original, file);
+      txn.edit(2, 4, '.');
+      txn.edit(3, 3, '-');
+      expect(() => txn.commit(), throwsA(predicate(
+            (e) => e.toString().contains('overlapping edits'))));
+    });
+  });
+
+  test('generated source maps', () {
+    var original =
+        "0123456789\n0*23456789\n01*3456789\nabcdefghij\nabcd*fghij\n";
+    var file = new SourceFile.text('', original);
+    var txn = new TextEditTransaction(original, file);
+    txn.edit(27, 29, '__\n    ');
+    txn.edit(34, 35, '___');
+    var printer = (txn.commit()..build(''));
+    var output = printer.text;
+    var map = parse(printer.map);
+    expect(output,
+        "0123456789\n0*23456789\n01*34__\n    789\na___cdefghij\nabcd*fghij\n");
+
+    // Line 1 and 2 are unmodified: mapping any column returns the beginning
+    // of the corresponding line:
+    expect(_span(1, 1, map, file), ":1:1: \n0123456789");
+    expect(_span(1, 5, map, file), ":1:1: \n0123456789");
+    expect(_span(2, 1, map, file), ":2:1: \n0*23456789");
+    expect(_span(2, 8, map, file), ":2:1: \n0*23456789");
+
+    // Line 3 is modified part way: mappings before the edits have the right
+    // mapping, after the edits the mapping is null.
+    expect(_span(3, 1, map, file), ":3:1: \n01*3456789");
+    expect(_span(3, 5, map, file), ":3:1: \n01*3456789");
+
+    // Start of edits map to beginning of the edit secion:
+    expect(_span(3, 6, map, file), ":3:6: \n01*3456789");
+    expect(_span(3, 7, map, file), ":3:6: \n01*3456789");
+
+    // Lines added have no mapping (they should inherit the last mapping),
+    // but the end of the edit region continues were we left off:
+    expect(_span(4, 1, map, file), isNull);
+    expect(_span(4, 5, map, file), ":3:8: \n01*3456789");
+
+    // Subsequent lines are still mapped correctly:
+    expect(_span(5, 1, map, file), ":4:1: \nabcdefghij"); // a (in a___cd...)
+    expect(_span(5, 2, map, file), ":4:2: \nabcdefghij"); // _ (in a___cd...)
+    expect(_span(5, 3, map, file), ":4:2: \nabcdefghij"); // _ (in a___cd...)
+    expect(_span(5, 4, map, file), ":4:2: \nabcdefghij"); // _ (in a___cd...)
+    expect(_span(5, 5, map, file), ":4:3: \nabcdefghij"); // c (in a___cd...)
+    expect(_span(6, 1, map, file), ":5:1: \nabcd*fghij");
+    expect(_span(6, 8, map, file), ":5:1: \nabcd*fghij");
+  });
+}
+
+String _span(int line, int column, Mapping map, SourceFile file) {
+  var span = map.spanFor(line - 1, column - 1, files: {'': file});
+  return span == null ? null : span.getLocationMessage('').trim();
+}