Bring the YAML package's style up to modern standards.

pkg/yaml/test/utils.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.
+
+library yaml.test.utils;
+
+import 'package:unittest/unittest.dart';
+import 'package:yaml/src/deep_equals.dart' as de;
+import 'package:yaml/yaml.dart';
+
+/// A matcher that validates that a closure or Future throws a [YamlException].
+final Matcher throwsYamlException = throwsA(new isInstanceOf<YamlException>());
+
+/// Returns a matcher that asserts that the value equals [expected].
+///
+/// This handles recursive loops and considers `NaN` to equal itself.
+Matcher deepEquals(expected) =>
+    predicate((actual) => de.deepEquals(actual, expected), "equals $expected");
+
+/// Constructs a new yaml.YamlMap, optionally from a normal Map.
+Map yamlMap([Map from]) =>
+    from == null ? new YamlMap() : new YamlMap.from(from);
+
+/// Asserts that a string containing a single YAML document produces a given
+/// value when loaded.
+void expectYamlLoads(expected, String source) {
+  var actual = loadYaml(cleanUpLiteral(source));
+  expect(expected, deepEquals(actual));
+}
+
+/// Asserts that a string containing a stream of YAML documents produces a given
+/// list of values when loaded.
+void expectYamlStreamLoads(List expected, String source) {
+  var actual = loadYamlStream(cleanUpLiteral(source));
+  expect(expected, deepEquals(actual));
+}
+
+/// Asserts that a string containing a single YAML document throws a
+/// [YamlException].
+void expectYamlFails(String source) {
+  expect(() => loadYaml(cleanUpLiteral(source)), throwsYamlException);
+}
+
+/// Removes eight spaces of leading indentation from a multiline string.
+///
+/// Note that this is very sensitive to how the literals are styled. They should
+/// be:
+///     '''
+///     Text starts on own line. Lines up with subsequent lines.
+///     Lines are indented exactly 8 characters from the left margin.
+///     Close is on the same line.'''
+///
+/// This does nothing if text is only a single line.
+String cleanUpLiteral(String text) {
+  var lines = text.split('\n');
+  if (lines.length <= 1) return text;
+
+  for (var j = 0; j < lines.length; j++) {
+    if (lines[j].length > 8) {
+      lines[j] = lines[j].substring(8, lines[j].length);
+    } else {
+      lines[j] = '';
+    }
+  }
+
+  return lines.join('\n');
+}
+
+/// Indents each line of [text] so that, when passed to [cleanUpLiteral], it
+/// will produce output identical to [text].
+///
+/// This is useful for literals that need to include newlines but can't be
+/// conveniently represented as multi-line strings.
+String indentLiteral(String text) {
+  var lines = text.split('\n');
+  if (lines.length <= 1) return text;
+
+  for (var i = 0; i < lines.length; i++) {
+    lines[i] = "        ${lines[i]}";
+  }
+
+  return lines.join("\n");
+}