remove code-transformers from the repo

pkg/code_transformers/lib/tests.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.
-
-/// Collection of utilities which are useful for creating unit tests for
-/// Barback transformers.
-library code_transformers.tests;
-
-import 'dart:async' show Future;
-import 'dart:io' show Platform;
-
-import 'package:barback/barback.dart' show Transformer;
-import 'package:path/path.dart' as path;
-import 'package:unittest/unittest.dart';
-
-import 'src/test_harness.dart';
-import 'src/dart_sdk.dart';
-
-/// Defines a test which invokes [applyTransformers].
-testPhases(String testName, List<List<Transformer>> phases,
-    Map<String, String> inputs, Map<String, String> results,
-    [List<String> messages]) {
-  test(testName,
-    () => applyTransformers(phases, inputs: inputs, results: results,
-        messages: messages));
-}
-
-/// Updates the provided transformers with [inputs] as asset inputs then
-/// validates that [results] were generated.
-///
-/// The keys for inputs and results are 'package_name|lib/file.dart'.
-/// Only files which are specified in results are validated.
-///
-/// If [messages] is non-null then this will validate that only the specified
-/// messages were generated, ignoring info messages.
-Future applyTransformers(List<List<Transformer>> phases,
-    {Map<String, String> inputs: const {},
-    Map<String, String> results: const {},
-    List<String> messages: const []}) {
-
-  var helper = new TestHelper(phases, inputs, messages)..run();
-  return helper.checkAll(results).then((_) => helper.tearDown());
-}
-
-/// Variant of [dartSdkDirectory] which includes additional cases only
-/// typically encountered in Dart's testing environment.
-String get testingDartSdkDirectory {
-  var sdkDir = dartSdkDirectory;
-  if (sdkDir == null) {
-    // If we cannot find the SDK dir, then assume this is being run from Dart's
-    // source directory and this script is the main script.
-    var segments = path.split(path.fromUri(Platform.script));
-    var index = segments.indexOf('pkg');
-    expect(index, greaterThan(0),
-        reason: 'testingDartSdkDirectory is only supported in pkg/ tests');
-    sdkDir = path.joinAll(segments.sublist(0, index)..add('sdk'));
-  }
-  return sdkDir;
-}