Add implementations of the front end FileSystem API.

pkg/front_end/test/memory_file_system_test.dart

+// Copyright (c) 2016, 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.
+// SharedOptions=--supermixin
+
+library front_end.test.memory_file_system_test;
+
+import 'dart:convert';
+import 'dart:io' as io;
+
+import 'package:front_end/memory_file_system.dart';
+import 'package:path/path.dart' as pathos;
+import 'package:test/test.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';

[Siggi Cherem (dart-lang), 2016/11/03 00:46:50]

I've never used this framework, we normally just use package:test alone. I'll
ask you offline later more about it. One concern I have if we later want to run
dart2js tests is whether this is using dart:mirrors, in which case it can make
the building and running of tests more expensive or slower than necessary.

[Paul Berry, 2016/11/03 15:16:41]

This framework adds a lot of functionality which has really helped make test
writing easier in analyzer (and which I believe will really help in the front
end as well).  But you're right that it comes at the cost of relying on mirrors.
 I'm going to commit it as is for now, but I agree that it would be good to talk
offline and make sure it's worth it.

+
+main() {
+  defineReflectiveSuite(() {
+    defineReflectiveTests(MemoryFileSystemTestNative);
+    defineReflectiveTests(MemoryFileSystemTestPosix);
+    defineReflectiveTests(MemoryFileSystemTestWindows);
+    defineReflectiveTests(FileTest);
+  });
+}
+
+@reflectiveTest
+class FileTest extends _BaseTestNative {
+  String path;
+  MemoryFileSystemEntity file;
+
+  setUp() {
+    super.setUp();
+    path = join(tempPath, 'file.txt');
+    file = fileSystem.entityForPath(path);
+  }
+
+  test_equals_differentPaths() {
+    expect(
+        file == fileSystem.entityForPath(join(tempPath, 'file2.txt')), isFalse);
+  }
+
+  test_equals_samePath() {
+    expect(
+        file == fileSystem.entityForPath(join(tempPath, 'file.txt')), isTrue);
+  }
+
+  test_hashCode_samePath() {
+    expect(file.hashCode,
+        fileSystem.entityForPath(join(tempPath, 'file.txt')).hashCode);
+  }
+
+  test_path() {
+    expect(file.path, path);
+  }
+
+  test_readAsBytes_badUtf8() async {
+    // A file containing invalid UTF-8 can still be read as raw bytes.
+    List<int> bytes = [0xc0, 0x40]; // Invalid UTF-8
+    file.writeAsBytesSync(bytes);
+    expect(await file.readAsBytes(), bytes);
+  }
+
+  test_readAsBytes_doesNotExist() {
+    expect(file.readAsBytes(), throwsException);
+  }
+
+  test_readAsBytes_exists() async {
+    var s = 'contents';
+    file.writeAsStringSync(s);
+    expect(await file.readAsBytes(), UTF8.encode(s));
+  }
+
+  test_readAsString_badUtf8() {
+    file.writeAsBytesSync([0xc0, 0x40]); // Invalid UTF-8
+    expect(file.readAsString(), throwsException);
+  }
+
+  test_readAsString_doesNotExist() {
+    expect(file.readAsString(), throwsException);
+  }
+
+  test_readAsString_exists() async {
+    var s = 'contents';
+    file.writeAsStringSync(s);
+    expect(await file.readAsString(), s);
+  }
+
+  test_readAsString_utf8() async {
+    file.writeAsBytesSync([0xe2, 0x82, 0xac]); // Unicode € symbol, in UTF-8
+    expect(await file.readAsString(), '\u20ac');
+  }
+
+  test_writeAsBytesSync_modifyAfterRead() async {
+    file.writeAsBytesSync([1]);
+    (await file.readAsBytes())[0] = 2;
+    expect(await file.readAsBytes(), [1]);
+  }
+
+  test_writeAsBytesSync_modifyAfterWrite() async {
+    var bytes = [1];
+    file.writeAsBytesSync(bytes);
+    bytes[0] = 2;
+    expect(await file.readAsBytes(), [1]);
+  }
+
+  test_writeAsBytesSync_overwrite() async {
+    file.writeAsBytesSync([1]);
+    file.writeAsBytesSync([2]);
+    expect(await file.readAsBytes(), [2]);
+  }
+
+  test_writeAsStringSync_overwrite() async {
+    file.writeAsStringSync('first');
+    file.writeAsStringSync('second');
+    expect(await file.readAsString(), 'second');
+  }
+
+  test_writeAsStringSync_utf8() async {
+    file.writeAsStringSync('\u20ac'); // Unicode € symbol
+    expect(await file.readAsBytes(), [0xe2, 0x82, 0xac]);
+  }
+}
+
+abstract class MemoryFileSystemTestMixin extends _BaseTest {
+  Uri tempUri;
+
+  setUp() {
+    super.setUp();
+    tempUri = fileSystem.context.toUri(tempPath);
+  }
+
+  test_entityForPath() {
+    var path = join(tempPath, 'file.txt');
+    expect(fileSystem.entityForPath(path).path, path);
+  }
+
+  test_entityForPath_absolutize() {
+    expect(fileSystem.entityForPath('file.txt').path,
+        join(fileSystem.currentDirectory, 'file.txt'));
+  }
+
+  test_entityForPath_normalize_dot() {
+    expect(fileSystem.entityForPath(join(tempPath, '.', 'file.txt')).path,
+        join(tempPath, 'file.txt'));
+  }
+
+  test_entityForPath_normalize_dotDot() {
+    expect(
+        fileSystem.entityForPath(join(tempPath, 'foo', '..', 'file.txt')).path,
+        join(tempPath, 'file.txt'));
+  }
+
+  test_entityForUri() {
+    expect(fileSystem.entityForUri(Uri.parse('$tempUri/file.txt')).path,
+        join(tempPath, 'file.txt'));
+  }
+
+  test_entityForUri_bareUri_absolute() {
+    expect(() => fileSystem.entityForUri(Uri.parse('/file.txt')),
+        throwsA(new isInstanceOf<Error>()));

[scheglov, 2016/11/03 02:15:24]

Maybe just test for the specific isArgumentError that is current thrown.

[Paul Berry, 2016/11/03 15:16:41]

The interface contract is that we simply throw an instance of `Error`.  If we
want to tighten the test, we should tighten the interface contract too, and IMHO
that's not worth doing.

Leaving as is, but I'm open to being convinced if you feel strongly about this.

+  }
+
+  test_entityForUri_bareUri_relative() {
+    expect(() => fileSystem.entityForUri(Uri.parse('file.txt')),
+        throwsA(new isInstanceOf<Error>()));
+  }
+
+  test_entityForUri_nonFileUri() {
+    expect(() => fileSystem.entityForUri(Uri.parse('package:foo/bar.dart')),
+        throwsA(new isInstanceOf<Error>()));
+  }
+
+  test_entityForUri_normalize_dot() {
+    expect(fileSystem.entityForUri(Uri.parse('$tempUri/./file.txt')).path,
+        join(tempPath, 'file.txt'));
+  }
+
+  test_entityForUri_normalize_dotDot() {
+    expect(fileSystem.entityForUri(Uri.parse('$tempUri/foo/../file.txt')).path,
+        join(tempPath, 'file.txt'));
+  }
+}
+
+@reflectiveTest
+class MemoryFileSystemTestNative extends _BaseTestNative
+    with MemoryFileSystemTestMixin {}
+
+@reflectiveTest
+class MemoryFileSystemTestPosix extends _BaseTestPosix
+    with MemoryFileSystemTestMixin {}
+
+@reflectiveTest
+class MemoryFileSystemTestWindows extends _BaseTestWindows
+    with MemoryFileSystemTestMixin {}
+
+abstract class _BaseTest {
+  MemoryFileSystem get fileSystem;
+  String get tempPath;
+  String join(String path1, String path2, [String path3, String path4]);
+  void setUp();
+}
+
+class _BaseTestNative extends _BaseTest {
+  MemoryFileSystem fileSystem;
+  String tempPath;
+
+  String join(String path1, String path2, [String path3, String path4]) =>
+      pathos.join(path1, path2, path3, path4);
+
+  setUp() {
+    tempPath = pathos.join(io.Directory.systemTemp.path, 'test_file_system');
+    fileSystem =
+        new MemoryFileSystem(pathos.context, io.Directory.current.path);
+  }
+}
+
+class _BaseTestPosix extends _BaseTest {
+  MemoryFileSystem fileSystem;
+  String tempPath;
+
+  String join(String path1, String path2, [String path3, String path4]) =>
+      pathos.posix.join(path1, path2, path3, path4);
+
+  void setUp() {
+    tempPath = '/test_file_system';
+    fileSystem = new MemoryFileSystem(pathos.posix, '/cwd');
+  }
+}
+
+class _BaseTestWindows extends _BaseTest {
+  MemoryFileSystem fileSystem;
+  String tempPath;
+
+  String join(String path1, String path2, [String path3, String path4]) =>
+      pathos.windows.join(path1, path2, path3, path4);
+
+  void setUp() {
+    tempPath = r'c:\test_file_system';
+    fileSystem = new MemoryFileSystem(pathos.windows, r'c:\cwd');
+  }
+}