Adding some asset-related utilities to code_transformers

pkg/code_transformers/test/assets_test.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 code_transformers.test.assets_test;
+
+import 'dart:async';
+import 'dart:io' show File, Platform;
+
+import 'package:barback/barback.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 checkDartEntry({Map<String, String> inputs, bool expectation}) {
+    var transformer = new Validator((transform) {
+      return isPossibleDartEntry(transform.primaryInput).then((value) {
+        expect(value, expectation);
+      });
+    });
+    return applyTransformers(
+          [[transformer]],
+          inputs: inputs);
+  }
+
+  group('isPossibleDartEntry', () {
+    test('should handle empty files', () {
+      return checkDartEntry(
+          inputs: {
+            'a|web/main.dart': '',
+          },
+          expectation: false);
+    });
+
+    test('should detect main methods', () {
+      return checkDartEntry(
+          inputs: {
+            'a|web/main.dart': 'main() {}',
+          },
+          expectation: true);
+    });
+
+    test('should exclude dart mains in lib folder', () {
+      return checkDartEntry(
+          inputs: {
+            'a|lib/main.dart': 'main() {}',
+          },
+          expectation: false);
+    });
+
+    test('should validate file extension', () {
+      return checkDartEntry(
+          inputs: {
+            'a|web/main.not_dart': 'main() {}',
+          },
+          expectation: false);
+    });
+
+    test('should count exports as main', () {
+      return checkDartEntry(
+          inputs: {
+            'a|web/main.dart': 'export "foo.dart";',
+          },
+          expectation: true);
+    });
+
+    test('should count parts as main', () {
+      return checkDartEntry(
+          inputs: {
+            'a|web/main.dart': 'part "foo.dart";',
+          },
+          expectation: true);
+    });
+  });
+
+  Future testAssetUri(String name,
+      {AssetId source, String uri, AssetId result}) {
+    test(name, () {
+      var transformer = new Validator((transform) {
+      var assetId = uriToAssetId(source, uri, transform.logger, null);
+        expect(result, assetId);
+      });
+      return applyTransformers(
+            [[transformer]],
+            inputs: {
+              source.toString(): ''
+            });
+    });
+  }
+
+  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 packages paths',
+        source: new AssetId('a', 'web/main.dart'),
+        uri: 'packages/foo/foo.dart',
+        result: new AssetId('foo', 'lib/foo.dart'));

[Siggi Cherem (dart-lang), 2014/03/18 16:42:16]

seems that we didn't have enough unittests in polymer for it (we have some
end-to-end tests in the polymer/example/canonicalization* packages)

Here are some additional tests that might be useful to include:
 - it is valid to use package: inside lib/.../foo.dart
 - it is invalid to use 'packages/foo/bar' in lib/foo.html
 - but it is valid to use '../../packages/foo/bar' in lib/foo.html
 - error message when assetId is .html, but uri uses "package:" or starts with
"/" (and !allowAbsolute)
 - null result when allowAbsolute is true (normally this is allowed in cases
like hrefs to external resources like .css)

[blois, 2014/03/18 17:39:07]

Done.

+  });
+}
+
+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));
+  }
+}