Add more CLI tests.

lib/src/executable.dart

@@ -21,8 +21,7 @@ main(List<String> args) async {
         help: 'Output style.',
         allowed: ['expanded'],
         defaultsTo: 'expanded')
-    ..addFlag('color',
-        abbr: 'c', help: 'Whether to emit terminal colors.', defaultsTo: true)
+    ..addFlag('color', abbr: 'c', help: 'Whether to emit terminal colors.')
     ..addFlag('trace', help: 'Print full Dart stack traces for exceptions.')
     ..addFlag('help',
         abbr: 'h', help: 'Print this usage information.', negatable: false)
@@ -46,7 +45,7 @@ main(List<String> args) async {
     return;
   }
 
-  var color = options['color'] as bool;
+  var color = (options['color'] as bool) ?? hasTerminal;
   try {
     var css = render(options.rest.first, color: color);
     if (css.isNotEmpty) print(css);

lib/src/io/interface.dart

@@ -20,6 +20,9 @@ class Stderr {
 /// The standard error for the current process.
 Stderr get stderr => null;
 
+/// Returns whether or not stdout is connected to an interactive terminal.
+bool get hasTerminal => false;
+
 /// Reads the file at [path].
 String readFile(String path) => null;
 

lib/src/io/node.dart

@@ -44,6 +44,11 @@ external _Stderr get _stderr;
 
 final stderr = new Stderr(_stderr);
 
+bool get hasTerminal => _hasTerminal ?? false;
+
+@JS("process.stdout.isTTY")
+external bool get _hasTerminal;
+
 @JS("process.exitCode")
 external int get exitCode;
 

lib/src/io/vm.dart

@@ -8,6 +8,8 @@ export 'dart:io' show exitCode;
 
 io.Stdout get stderr => io.stderr;
 
+bool get hasTerminal => io.stdout.hasTerminal;
+
 String readFile(String path) => new io.File(path).readAsStringSync();
 
 bool fileExists(String path) => new io.File(path).existsSync();

test/cli_shared.dart

@@ -2,20 +2,97 @@
 // MIT-style license that can be found in the LICENSE file or at
 // https://opensource.org/licenses/MIT.
 
+import 'package:scheduled_test/descriptor.dart' as d;
 import 'package:scheduled_test/scheduled_process.dart';
 import 'package:scheduled_test/scheduled_stream.dart';
 import 'package:scheduled_test/scheduled_test.dart';
 
+import 'utils.dart';
+
 /// Defines test that are shared between the Dart and Node.js CLI test suites.
-void sharedTests(
-    ScheduledProcess startExecutable(List arguments, {workingDirectory})) {
+void sharedTests(ScheduledProcess runSass(List arguments)) {
+  useSandbox();
+
   test("--help prints the usage documentation", () {
     // Checking the entire output is brittle, so just do a sanity check to make
     // sure it's not totally busted.
-    var sass = startExecutable(["--help"]);
+    var sass = runSass(["--help"]);
     sass.stdout.expect("Compile Sass to CSS.");
     sass.stdout
         .expect(consumeThrough(contains("Print this usage information.")));
     sass.shouldExit(64);
   });
+
+  test("compiles a Sass file to CSS", () {
+    d.file("test.scss", "a {b: 1 + 2}").create();
+
+    var sass = runSass(["test.scss", "test.css"]);
+    sass.stdout.expect(inOrder([
+      "a {",
+      "  b: 3;",
+      "}",
+    ]));
+    sass.shouldExit(0);
+  });
+
+  test("supports relative imports", () {
+    d.file("test.scss", "@import 'dir/test'").create();
+
+    d.dir("dir", [d.file("test.scss", "a {b: 1 + 2}")]).create();
+
+    var sass = runSass(["test.scss", "test.css"]);
+    sass.stdout.expect(inOrder([
+      "a {",
+      "  b: 3;",
+      "}",
+    ]));
+    sass.shouldExit(0);
+  });
+
+  test("gracefully reports syntax errors", () {
+    d.file("test.scss", "a {b: }").create();
+
+    var sass = runSass(["test.scss", "test.css"]);
+    sass.stderr.expect(inOrder([
+      "Error: Expected expression.",
+      "a {b: }",
+      "      ^",
+      "  test.scss 1:7",
+    ]));
+    sass.shouldExit(65);
+  });
+
+  test("gracefully reports runtime errors", () {
+    d.file("test.scss", "a {b: 1px + 1deg}").create();
+
+    var sass = runSass(["test.scss", "test.css"]);
+    sass.stderr.expect(inOrder([
+      "Error: Incompatible units deg and px.",
+      "a {b: 1px + 1deg}",
+      "      ^^^^^^^^^^",
+      "  test.scss 1:7  root stylesheet",
+    ]));
+    sass.shouldExit(65);
+  });
+
+  test("reports errors with colors with --color", () {
+    d.file("test.scss", "a {b: }").create();
+
+    var sass = runSass(["--color", "test.scss", "test.css"]);
+    sass.stderr.expect(inOrder([
+      "Error: Expected expression.",
+      "a {b: \u001b[31m\u001b[0m}",
+      "      \u001b[31m^\u001b[0m",
+      "  test.scss 1:7",
+    ]));
+    sass.shouldExit(65);
+  });
+
+  test("prints full stack traces with --trace", () {
+    d.file("test.scss", "a {b: }").create();
+
+    var sass = runSass(["--trace", "test.scss", "test.css"]);
+    sass.stderr.expect(consumeThrough(contains("\.dart")));
+    sass.shouldExit(65);
+  });
 }

test/dart_cli_test.dart

@@ -4,12 +4,25 @@
 
 import 'dart:io';
 
+import 'package:path/path.dart' as p;
 import 'package:scheduled_test/scheduled_process.dart';
+import 'package:scheduled_test/scheduled_test.dart';
 
 import 'cli_shared.dart';
+import 'utils.dart';
 
 void main() {
-  sharedTests((arguments, {workingDirectory}) => new ScheduledProcess.start(
-      Platform.executable, <Object>["bin/sass.dart"]..addAll(arguments),
-      workingDirectory: workingDirectory, description: "sass"));
+  sharedTests(_runSass);
+
+  test("--version prints the Sass version", () {
+    var sass = _runSass(["--version"]);
+    sass.stdout.expect(matches(new RegExp(r"^\d+\.\d+\.\d+")));
+    sass.shouldExit(0);
+  });
 }
+
+ScheduledProcess _runSass(List arguments) => new ScheduledProcess.start(
+    Platform.executable,
+    <Object>[p.absolute("bin/sass.dart")]..addAll(arguments),
+    workingDirectory: sandbox,
+    description: "sass");

test/node_cli_test.dart

@@ -3,13 +3,14 @@
 // https://opensource.org/licenses/MIT.
 
 @Tags(const ['node'])
-
 import 'dart:io';
 
+import 'package:path/path.dart' as p;
 import 'package:scheduled_test/scheduled_process.dart';
 import 'package:scheduled_test/scheduled_test.dart';
 
 import 'cli_shared.dart';
+import 'utils.dart';
 
 void main() {
   setUpAll(() {
@@ -18,7 +19,16 @@ void main() {
     grinder.shouldExit(0);
   });
 
-  sharedTests((arguments, {workingDirectory}) => new ScheduledProcess.start(
-      "node", <Object>["build/npm/sass.js"]..addAll(arguments),
-      workingDirectory: workingDirectory, description: "sass"));
+  sharedTests(_runSass);
+
+  test("--version prints the Sass and dart2js versions", () {
+    var sass = _runSass(["--version"]);
+    sass.stdout.expect(matches(
+        new RegExp(r"^\d+\.\d+\.\d+.* compiled with dart2js \d+\.\d+\.\d+")));
+    sass.shouldExit(0);
+  });
 }
+
+ScheduledProcess _runSass(List arguments) => new ScheduledProcess.start(
+    "node", <Object>[p.absolute("build/npm/sass.js")]..addAll(arguments),
+    workingDirectory: sandbox, description: "sass");

test/utils.dart

@@ -0,0 +1,36 @@
+// Copyright 2016 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:io';
+
+import 'package:scheduled_test/descriptor.dart' as d;
+import 'package:scheduled_test/scheduled_test.dart';
+
+/// The path to the sandbox directory.
+///
+/// This is only set in tests for which [useSandbox] is active.
+String get sandbox => _sandbox;
+String _sandbox;
+
+/// Declares a [setUp] function that creates a sandbox diretory and sets it as
+/// the default for scheduled_test's directory descriptors.
+///
+/// This should be called outside of any tests.
+void useSandbox() {
+  setUp(() {
+    _sandbox = Directory.systemTemp.createTempSync("dart-sass-test").path;
+    d.defaultRoot = _sandbox;
+
+    currentSchedule.onComplete.schedule(() {
+      try {
+        new Directory(_sandbox).deleteSync(recursive: true);
+      } on IOException catch (_) {
+        // Silently swallow exceptions on Windows. If the test failed, there may
+        // still be lingering processes that have files in the sandbox open,
+        // which will cause this to fail on Windows.
+        if (!Platform.isWindows) rethrow;
+      }
+    }, 'deleting the sandbox directory');
+  });
+}