extract resource path test utils

pkg/analyzer/test/resource_utils.dart

+// Copyright (c) 2015, 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 analyzer.test.resource_utils;
+
+import 'dart:core' hide Resource;
+
+import 'package:analyzer/file_system/file_system.dart';
+import 'package:analyzer/file_system/memory_file_system.dart';
+import 'package:analyzer/src/util/absolute_path.dart';
+import 'package:path/path.dart' as path;
+import 'package:unittest/unittest.dart';
+
+
+bool get isWindows => path.Style.platform == path.Style.windows;
+
+/**
+ * Assert that the given path is posix and absolute.
+ */
+void expectAbsolutePosixPath(String posixPath) {
+  expect(posixPath, startsWith('/'),
+      reason: 'Expected absolute posix path, but found $posixPath');
+}
+
+/**
+ * Assert that the given path is posix.
+ */
+void expectPosixPath(String posixPath) {
+  expect(posixPath.indexOf('\\'), -1,
+      reason: 'Expected posix path, but found $posixPath');
+}
+
+/**
+ * Translate the given posixPath to a path appropriate for the
+ * platform on which the tests are executing.
+ */
+String posixToOSPath(String posixPath) {
+  expectPosixPath(posixPath);
+  if (isWindows) {
+    String windowsPath = posixPath.replaceAll('/', '\\');
+    if (posixPath.startsWith('/')) {
+      return 'C:$windowsPath';
+    }
+    return windowsPath;
+  }
+  return posixPath;
+}
+
+/**
+ * Translate the given posixPath to a file URI appropriate for the
+ * platform on which the tests are executing.
+ */
+String posixToOSFileUri(String posixPath) {
+  expectPosixPath(posixPath);
+  return isWindows ? 'file:///C:$posixPath' : 'file://$posixPath';
+}
+
+/**
+ * A convenience utility for setting up a test [MemoryResourceProvider].
+ * All supplied paths are assumed to be in [path.posix] format
+ * and are automatically translated to [path.context].
+ *
+ * This class intentionally does not implement [ResourceProvider]
+ * directly or indirectly so that it cannot be used as a resource provider.
+ * We do not want functionality under test to interact with a resource provider
+ * that automatically translates paths.
+ */
+class TestPathTranslator {
+  final MemoryResourceProvider _provider;
+
+  TestPathTranslator(this._provider);
+
+  Resource getResource(String posixPath) =>
+      _provider.getResource(posixToOSPath(posixPath));
+
+  File newFile(String posixPath, String content) =>
+      _provider.newFile(posixToOSPath(posixPath), content);
+
+  Folder newFolder(String posixPath) =>
+      _provider.newFolder(posixToOSPath(posixPath));
+}
+
+/**
+ * A resource provider for testing that asserts that any supplied paths
+ * are appropriate for the OS platform on which the tests are running.
+ */
+class TestResourceProvider implements ResourceProvider {
+  final ResourceProvider _provider;
+
+  TestResourceProvider(this._provider) {
+    expect(_provider.absolutePathContext.separator, isWindows ? '\\' : '/');
+  }
+
+  @override
+  AbsolutePathContext get absolutePathContext => _provider.absolutePathContext;
+
+  @override
+  File getFile(String path) => _provider.getFile(_assertPath(path));
+
+  @override
+  Folder getFolder(String path) => _provider.getFolder(_assertPath(path));
+
+  @override
+  Resource getResource(String path) => _provider.getResource(_assertPath(path));
+
+  @override
+  Folder getStateLocation(String pluginId) =>
+      _provider.getStateLocation(pluginId);
+
+  @override
+  path.Context get pathContext => _provider.pathContext;
+
+  /**
+   * Assert that the given path is valid for the OS platform on which the
+   * tests are running.
+   */
+  String _assertPath(String path) {
+    if (isWindows) {
+      if (path.contains('/')) {
+        fail('Expected windows path, but found: $path');
+      }
+    } else {
+      if (path.contains('\\')) {
+        fail('Expected posix path, but found: $path');
+      }
+    }
+    return path;
+  }
+}