Correctly match and print strings with escaped values

test/escape_test.dart

+// Copyright (c) 2015, 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 matcher.escape_test;
+
+import 'package:unittest/unittest.dart';
+
+import 'package:matcher/src/escape.dart';

[nweiz, 2015/02/04 01:34:46]

All "package:" imports should be in a single block, even if they're for the
current package.

[kevmoo, 2015/02/04 05:28:21]

Done.

+
+void main() {
+  group('escaping should work with', () {
+    _testEscaping('no escaped chars', 'Hello, world!', 'Hello, world!');
+    _testEscaping('newline', '\n', r'\n');
+    _testEscaping('carriage return', '\r', r'\r');
+    _testEscaping('form feed', '\f', r'\f');
+    _testEscaping('backspace', '\b', r'\b');
+    _testEscaping('tab', '\t', r'\t');
+    _testEscaping('vertical tab', '\v', r'\v');
+    _testEscaping('escape combos', r'\n', r'\\n');
+  });
+
+  group('unequal strings remain unequal when escaped', () {
+    _testUnequalStrings('with a newline', '\n', r'\n');
+    _testUnequalStrings('with slash literals', '\\', r'\\');
+  });
+}
+
+void _testEscaping(String k, String source, String target) {

[nweiz, 2015/02/04 01:34:46]

Document these functions and don't use single-letter variable names, here and
below.

[kevmoo, 2015/02/04 05:28:21]

Done.

+  test(k, () {
+    expect(escape(source) == target, isTrue);
+  });
+}
+
+void _testUnequalStrings(String name, String s1, String s2) {
+  test(name, () {
+    // Explicitly not using the equals matcher
+    expect(s1 != s2, isTrue, reason: 'The source values should be unequal');
+
+    var escapedS1 = escape(s1);
+    var escapedS2 = escape(s2);
+
+    // Explicitly not using the equals matcher
+    expect(escapedS1 != escapedS2, isTrue,
+        reason: 'Unequal strings, when escaped, should remain unequal.');
+  });
+}