Adding some asset-related utilities to code_transformers

pkg/code_transformers/test/assets_test.dart

Index: pkg/code_transformers/test/assets_test.dart
diff --git a/pkg/code_transformers/test/assets_test.dart b/pkg/code_transformers/test/assets_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..0d104dd650e6e066e8532065e2f5dde82834b265
--- /dev/null
+++ b/pkg/code_transformers/test/assets_test.dart
@@ -0,0 +1,110 @@
+// 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 code_transformers.test.assets_test;
+
+import 'dart:async';
+import 'dart:io' show File, Platform;
+
+import 'package:barback/barback.dart';
+import 'package:code_transformers/assets.dart';
+import 'package:code_transformers/resolver.dart';
+import 'package:code_transformers/tests.dart';
+import 'package:path/path.dart' as path;
+import 'package:unittest/compact_vm_config.dart';
+import 'package:unittest/unittest.dart';
+
+main() {
+  useCompactVMConfiguration();
+
+
+  Future testAssetUri(String name,
+      {AssetId source, String uri, AssetId result, String message,
+      bool errorOnAbsolute: true}) {
+    test(name, () {
+      var transformer = new Validator((transform) {
+      var assetId = uriToAssetId(source, uri, transform.logger, null,
+          errorOnAbsolute: errorOnAbsolute);
+        expect(assetId, result);
+      });
+      var messages = [];
+      if (message != null) messages.add(message);
+
+      return applyTransformers(
+            [[transformer]],
+            inputs: {
+              source.toString(): ''
+            },
+            messages: messages);
+    });
+  }
+
+  group('uriToAssetId', () {
+    testAssetUri('resolves relative URIs',
+        source: new AssetId('a', 'web/main.dart'),
+        uri: 'foo.dart',
+        result: new AssetId('a', 'web/foo.dart'));
+
+    testAssetUri('resolves package: URIs',
+        source: new AssetId('a', 'web/main.dart'),
+        uri: 'package:foo/foo.dart',
+        result: new AssetId('foo', 'lib/foo.dart'));
+
+    testAssetUri('resolves package: URIs from libs',
+        source: new AssetId('a', 'lib/main.dart'),
+        uri: 'package:foo/foo.dart',
+        result: new AssetId('foo', 'lib/foo.dart'));
+
+    testAssetUri('resolves packages paths',
+        source: new AssetId('a', 'web/main.dart'),
+        uri: 'packages/foo/foo.dart',
+        result: new AssetId('foo', 'lib/foo.dart'));
+
+    testAssetUri('resolves relative packages paths',
+        source: new AssetId('a', 'web/main.dart'),
+        uri: 'packages/foo/foo.dart',
+        result: new AssetId('foo', 'lib/foo.dart'));
+
+    testAssetUri('does not allow packages from non-dart lib files',
+        source: new AssetId('a', 'lib/index.html'),
+        uri: 'packages/foo/bar',
+        message: 'error: Invalid url to reach to another package: '
+            'packages/foo/bar. Path reaching to other packages must first '
+            'reach up all the way to the packages folder. For example, try '
+            'changing the url above to: ../../packages/foo/bar');
+
+    testAssetUri('allows relative packages from non-dart lib files',
+        source: new AssetId('a', 'lib/index.html'),
+        uri: '../../packages/foo/bar',
+        result: new AssetId('foo', 'lib/bar'));
+
+    testAssetUri('does not allow package: imports from non-dart files',
+        source: new AssetId('a', 'lib/index.html'),
+        uri: 'package:foo/bar.dart',
+        message: 'error: absolute paths not allowed: "package:foo/bar.dart"');
+
+    testAssetUri('does not allow absolute /packages by default',
+        source: new AssetId('a', 'lib/index.html'),
+        uri: '/packages/foo/bar.dart',
+        message: 'error: absolute paths not allowed: "/packages/foo/bar.dart"');
+
+    testAssetUri('can suppress error on absolute /packages ',
+        source: new AssetId('a', 'lib/index.html'),
+        uri: '/packages/foo/bar.dart',
+        errorOnAbsolute: false,
+        result: null);
+  });
+}
+
+class Validator extends Transformer {
+  final Function validation;
+
+  Validator(this.validation);
+
+  Future<bool> isPrimary(Asset input) => new Future.value(true);
+
+  Future apply(Transform transform) {
+    return new Future.value(validation(transform));
+  }
+}