Test the Node.js API.

Closes #150

lib/src/node.dart

@@ -6,10 +6,11 @@ import 'package:js/js.dart';
 
 import 'exception.dart';
 import 'executable.dart' as executable;
-import 'node/error.dart';
 import 'node/exports.dart';
-import 'node/options.dart';
+import 'node/render_error.dart';
-import 'node/result.dart';
+import 'node/render_options.dart';
+import 'node/render_result.dart';
+import 'node/utils.dart';
 import 'render.dart';
 import 'visitor/serialize.dart';
 
@@ -35,22 +36,17 @@ void main() {
 /// possible.
 ///
 /// [render]: https://github.com/sass/node-sass#options
-void _render(
+void _render(RenderOptions options,
-    NodeOptions options, void callback(NodeError error, NodeResult result)) {
+    void callback(RenderError error, RenderResult result)) {
   try {
-    var indentWidthValue = options.indentWidth;
+    var result = newRenderResult(render(options.file,
-    var indentWidth = indentWidthValue is int
+        useSpaces: options.indentType != 'tab',
-        ? indentWidthValue
+        indentWidth: _parseIndentWidth(options.indentWidth),
-        : int.parse(indentWidthValue.toString());
+        lineFeed: _parseLineFeed(options.linefeed)));
-    var lineFeed = _parseLineFeed(options.linefeed);
-    var result = newNodeResult(render(options.file,
-        useSpaces: options.indentType == 'space',
-        indentWidth: indentWidth,
-        lineFeed: lineFeed));
     callback(null, result);
   } on SassException catch (error) {
     // TODO: populate the error more thoroughly if possible.
-    callback(new NodeError(message: error.message), null);
+    callback(newRenderError(message: error.message), null);
   }
 }
 
@@ -60,23 +56,25 @@ void _render(
 /// as possible.
 ///
 /// [render]: https://github.com/sass/node-sass#options
-NodeResult _renderSync(NodeOptions options) {
+RenderResult _renderSync(RenderOptions options) {
   try {
-    var indentWidthValue = options.indentWidth;
+    return newRenderResult(render(options.file,
-    var indentWidth = indentWidthValue is int
+        useSpaces: options.indentType != 'tab',
-        ? indentWidthValue
+        indentWidth: _parseIndentWidth(options.indentWidth),
-        : int.parse(indentWidthValue.toString());
+        lineFeed: _parseLineFeed(options.linefeed)));
-    var lineFeed = _parseLineFeed(options.linefeed);
-    return newNodeResult(render(options.file,
-        useSpaces: options.indentType == 'space',
-        indentWidth: indentWidth,
-        lineFeed: lineFeed));
   } on SassException catch (error) {
     // TODO: populate the error more thoroughly if possible.
-    throw new NodeError(message: error.message);
+    jsThrow(newRenderError(message: error.message));
+    throw "unreachable";
   }
 }
 
+/// Parses the indentation width into an [int].
+int _parseIndentWidth(width) {
+  if (width == null) return null;
+  return width is int ? width : int.parse(width.toString());
+}
+
 /// Parses the name of a line feed type into a [LineFeed].
 LineFeed _parseLineFeed(String str) {
   switch (str) {

lib/src/node/function.dart

@@ -0,0 +1,13 @@
+// Copyright 2017 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'package:js/js.dart';
+
+@JS("Function")
+class JSFunction {
+  @JS("Function")
+  external JSFunction(String arg1, [String arg2, String arg3]);
+
+  external call(thisArg, [arg1, arg2]);
+}

lib/src/node/render_error.dart

@@ -4,15 +4,25 @@
 
 import 'package:js/js.dart';
 
+import 'utils.dart';
+
 @JS()
 @anonymous
-class NodeError {
+class RenderError {
   external String get message;
   external int get line;
   external int get column;
   external int get status;
   external String get file;
 
-  external factory NodeError(
+  external factory RenderError._(
       {String message, int line, int column, int status, String file});
 }
+
+RenderError newRenderError(
+    {String message, int line, int column, int status, String file}) {
+  var error = new RenderError._(
+      message: message, line: line, column: column, status: status, file: file);
+  setToString(error, () => "Error: $message");
+  return error;
+}

lib/src/node/render_options.dart

@@ -5,9 +5,13 @@
 import 'package:js/js.dart';
 
 @JS()
-class NodeOptions {
+@anonymous
+class RenderOptions {
   external String get file;
   external String get indentType;
   external dynamic get indentWidth;
   external String get linefeed;
+
+  external factory RenderOptions(
+      {String file, String indentType, indentWidth, String linefeed});
 }

lib/src/node/render_result.dart

@@ -2,6 +2,8 @@
 // MIT-style license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
+import 'dart:typed_data';
+
 import 'package:js/js.dart';
 
 @JS('Buffer.from')
@@ -9,11 +11,11 @@ external _buffer(String source, String encoding);
 
 @JS()
 @anonymous
-class NodeResult {
+class RenderResult {
-  external get buffer;
+  external Uint8List get css;
 
-  external factory NodeResult._({buffer});
+  external factory RenderResult._({css});
 }
 
-NodeResult newNodeResult(String css) =>
+RenderResult newRenderResult(String css) =>
-    new NodeResult._(buffer: _buffer(css, 'utf8'));
+    new RenderResult._(css: _buffer(css, 'utf8'));

lib/src/node/utils.dart

@@ -0,0 +1,23 @@
+// Copyright 2017 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'package:js/js.dart';
+import 'package:meta/meta.dart';
+
+import 'function.dart';
+
+/// Sets the `toString()` function for [object] to [body].
+///
+/// Dart's JS interop doesn't currently let us set toString() for custom
+/// classes, so we use this as a workaround.
+void setToString(object, String body()) =>
+    _setToString.call(object, allowInterop(body));
+
+final _setToString =
+    new JSFunction("object", "body", "object.toString = body;");
+
+/// Throws [error] like JS would, without any Dart wrappers.
+void jsThrow(error) => _jsThrow.call(error);
+
+final _jsThrow = new JSFunction("error", "throw error;");

pubspec.yaml

@@ -28,8 +28,15 @@ dev_dependencies:
   http: "^0.11.0"
   js: "^0.6.0"
   node_preamble: "^1.1.0"
+  stream_channel: "^1.0.0"
   test_descriptor: "^1.0.0"
   test_process: "^1.0.0-rc.1"
-  test: "^0.12.5"
+  test: "^0.12.24"
   xml: "^2.4.0"
   yaml: "^2.0.0"
+
+dependency_overrides:
+  test:
+    git:
+      url: git://github.com/dart-lang/test.git
+      ref: node

test/dart_cli_test.dart

@@ -2,6 +2,8 @@
 // MIT-style license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
+@TestOn('vm')
+
 import 'dart:async';
 import 'dart:io';
 

test/dart_script_test.dart

@@ -2,6 +2,8 @@
 // MIT-style license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
+@TestOn('vm')
+
 import 'package:package_resolver/package_resolver.dart';
 import 'package:path/path.dart' as p;
 import 'package:test/test.dart';

test/ensure_npm_package.dart

@@ -6,22 +6,25 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
+import 'package:stream_channel/stream_channel.dart';
 import 'package:test/test.dart';
 import 'package:yaml/yaml.dart';
 
-void hybridMain(StreamChannel channel) async {
+hybridMain(StreamChannel channel) async {
   if (!new Directory("build/npm").existsSync()) {
     throw "NPM package is not build. Run pub run grinder npm_package.";
   }
 
   var lastModified = new DateTime(0);
   var entriesToCheck = new Directory("lib").listSync(recursive: true).toList()
-    ..add("pubspec.lock");
+    ..add(new File("pubspec.lock"));
   for (var entry in entriesToCheck) {
-    if (entry is! File) continue;
+    if (entry is File) {
-    var entryLastModified = entry.lastModifiedSync();
+      var entryLastModified = entry.lastModifiedSync();
-    if (lastModified.isBefore(entryLastModified))
+      if (lastModified.isBefore(entryLastModified)) {
-      lastModified = entryLastModified;
+        lastModified = entryLastModified;
+      }
+    }
   }
 
   if (lastModified

test/hybrid.dart

@@ -0,0 +1,56 @@
+// Copyright 2017 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'dart:async';
+import 'dart:convert';
+
+import 'package:test/test.dart';
+
+/// Creates a directory in the system temp directory and returns its path.
+Future<String> createTempDir() async => (await runHybridExpression(
+    '(await Directory.systemTemp.createTemp("dart_sass_")).path')) as String;
+
+/// Writes [text] to [path].
+Future writeTextFile(String path, String text) => runHybridExpression(
+    'new File(message[0]).writeAsString(message[1])', [path, text]);
+
+/// Recursively deletes the directoy at [path].
+Future deleteDirectory(String path) =>
+    runHybridExpression('new Directory(message).delete(recursive: true)', path);
+
+/// Runs [expression], which may be asynchronous, in a hybrid isolate.
+///
+/// Returns the result of [expression] if it's JSON-serializable.
+Future runHybridExpression(String expression, [message]) async {
+  var channel = spawnHybridCode(
+      '''
+    import 'dart:async';
+    import 'dart:convert';
+    import 'dart:io';
+
+    import 'package:stream_channel/stream_channel.dart';
+
+    hybridMain(StreamChannel channel, message) async {
+      var result = await ${expression};
+      channel.sink.add(_isJsonSafe(result) ? JSON.encode(result) : 'null');
+      channel.sink.close();
+    }
+
+    bool _isJsonSafe(object) {
+      if (object == null) return true;
+      if (object is String) return true;
+      if (object is num) return true;
+      if (object is bool) return true;
+      if (object is List) return object.every(_isJsonSafe);
+      if (object is Map) {
+        return object.keys.every(_isJsonSafe) &&
+            object.values.every(_isJsonSafe);
+      }
+      return false;
+    }
+  ''',
+      message: message);
+
+  return JSON.decode((await channel.stream.first) as String);
+}

test/node_api.dart

@@ -0,0 +1,33 @@
+// Copyright 2017 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+/// This library exposes Dart Sass's Node.js API, imported as JavaScript, back
+/// to Dart. This is kind of convoluted, but it allows us to test the API as it
+/// will be used in the real world without having to manually write any JS.
+
+import 'dart:typed_data';
+
+import 'package:sass/src/node/render_error.dart';
+import 'package:sass/src/node/render_options.dart';
+import 'package:sass/src/node/render_result.dart';
+
+import 'package:js/js.dart';
+import 'package:path/path.dart' as p;
+
+export 'package:sass/src/node/render_error.dart';
+export 'package:sass/src/node/render_options.dart';
+export 'package:sass/src/node/render_result.dart';
+
+/// The Sass module.
+final sass = _require(p.absolute("build/npm/sass.dart"));
+
+@JS("require")
+external Sass _require(String path);
+
+@JS()
+class Sass {
+  external RenderResult renderSync(RenderOptions args);
+  external void render(RenderOptions args,
+      void callback(RenderError error, RenderResult result));
+}

test/node_api_test.dart

@@ -0,0 +1,166 @@
+// Copyright 2017 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+@TestOn('node')
+@Tags(const ['node'])
+
+import 'dart:async';
+import 'dart:convert';
+
+import 'package:js/js.dart';
+import 'package:path/path.dart' as p;
+import 'package:test/test.dart';
+
+import 'ensure_npm_package.dart';
+import 'hybrid.dart';
+import 'node_api.dart';
+
+String sandbox;
+String sassPath;
+
+void main() {
+  setUpAll(ensureNpmPackage);
+
+  setUp(() async {
+    sandbox = await createTempDir();
+    sassPath = p.join(sandbox, 'test.scss');
+    await writeTextFile(sassPath, 'a {b: c}');
+  });
+
+  tearDown(() async {
+    if (sandbox != null) await deleteDirectory(sandbox);
+  });
+
+  group("renderSync()", () {
+    test("renders a file", () {
+      expect(_renderSync(new RenderOptions(file: sassPath)), equals('''
+a {
+  b: c;
+}'''));
+    });
+
+    test("allows tab indentation", () {
+      expect(_renderSync(new RenderOptions(file: sassPath, indentType: 'tab')),
+          equals('''
+a {
+\t\tb: c;
+}'''));
+    });
+
+    test("allows unknown indentation names", () {
+      expect(_renderSync(new RenderOptions(file: sassPath, indentType: 'asdf')),
+          equals('''
+a {
+  b: c;
+}'''));
+    });
+
+    group("linefeed allows", () {
+      test("cr", () {
+        expect(_renderSync(new RenderOptions(file: sassPath, linefeed: 'cr')),
+            equals('a {\r  b: c;\r}'));
+      });
+
+      test("crlf", () {
+        expect(_renderSync(new RenderOptions(file: sassPath, linefeed: 'crlf')),
+            equals('a {\r\n  b: c;\r\n}'));
+      });
+
+      test("lfcr", () {
+        expect(_renderSync(new RenderOptions(file: sassPath, linefeed: 'lfcr')),
+            equals('a {\n\r  b: c;\n\r}'));
+      });
+
+      test("unknown names", () {
+        expect(_renderSync(new RenderOptions(file: sassPath, linefeed: 'asdf')),
+            equals('a {\n  b: c;\n}'));
+      });
+    });
+
+    group("indentWidth allows", () {
+      test("a number", () {
+        expect(_renderSync(new RenderOptions(file: sassPath, indentWidth: 10)),
+            equals('''
+a {
+          b: c;
+}'''));
+      });
+
+      test("a string", () {
+        expect(_renderSync(new RenderOptions(file: sassPath, indentWidth: '1')),
+            equals('''
+a {
+ b: c;
+}'''));
+      });
+    });
+
+    group("throws an error that", () {
+      setUp(() => writeTextFile(sassPath, 'a {b: }'));
+
+      test("has a useful toString", () {
+        var error = _renderSyncError(new RenderOptions(file: sassPath));
+        expect(error.toString(), equals("Error: Expected expression."));
+      });
+
+      test("has a useful message", () {
+        var error = _renderSyncError(new RenderOptions(file: sassPath));
+        expect(error.message, equals("Expected expression."));
+      });
+    });
+  });
+
+  group("render()", () {
+    test("renders a file", () async {
+      expect(await _render(new RenderOptions(file: sassPath)), equals('''
+a {
+  b: c;
+}'''));
+    });
+
+    test("throws an error that has a useful toString", () async {
+      await writeTextFile(sassPath, 'a {b: }');
+
+      var error = await _renderError(new RenderOptions(file: sassPath));
+      expect(error.toString(), equals("Error: Expected expression."));
+    });
+  });
+}
+
+/// Returns the result of rendering via [options] as a string.
+Future<String> _render(RenderOptions options) {
+  var completer = new Completer<String>();
+  sass.render(options, allowInterop((error, result) {
+    expect(error, isNull);
+    completer.complete(UTF8.decode(result.css));
+  }));
+  return completer.future;
+}
+
+/// Asserts that rendering via [options] produces an error, and returns that
+/// error.
+Future<RenderError> _renderError(RenderOptions options) {
+  var completer = new Completer<RenderError>();
+  sass.render(options, allowInterop((error, result) {
+    expect(result, isNull);
+    completer.complete(error as RenderError);
+  }));
+  return completer.future;
+}
+
+/// Returns the result of rendering via [options] as a string.
+String _renderSync(RenderOptions options) =>
+    UTF8.decode(sass.renderSync(options).css);
+
+/// Asserts that rendering via [options] produces an error, and returns that
+/// error.
+RenderError _renderSyncError(RenderOptions options) {
+  try {
+    sass.renderSync(options);
+  } catch (error) {
+    return error as RenderError;
+  }
+
+  throw "Expected renderSync() to throw an error.";
+}

test/node_cli_test.dart

@@ -2,7 +2,9 @@
 // MIT-style license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
+@TestOn('vm')
 @Tags(const ['node'])
+
 import 'dart:async';
 import 'dart:io';