File watching package.

pkg/watcher/test/utils.dart

+// Copyright (c) 2012, 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 watcher.test.utils;
+
+import 'dart:async';
+import 'dart:io';
+
+import 'package:pathos/path.dart' as pathos;
+import 'package:scheduled_test/scheduled_test.dart';
+import 'package:unittest/compact_vm_config.dart';
+import 'package:watcher/watcher.dart';
+import 'package:watcher/src/stat.dart';
+
+/// The path to the temporary sandbox created for each test. All file
+/// operations are implicitly relative to this directory.
+String _sandboxDir;
+
+/// The [DirectoryWatcher] being used for the current scheduled test.
+DirectoryWatcher _watcher;
+
+/// The index in [_watcher]'s event stream for the next event. When event
+/// expectations are set using [expectEvent] (et. al.), they use this to
+/// expect a series of events in order.
+var _nextEvent = 0;
+
+/// The mock modification times (in milliseconds since epoch) for each file.
+///
+/// The actual file system has pretty coarse granularity for file modification
+/// times. This means using the real file system requires us to put delays in
+/// the tests to ensure we wait long enough between operations for the mod time
+/// to be different.
+///
+/// Instead, we'll just mock that out. Each time a file is written, we manually
+/// increment the mod time for that file instantly.
+Map<String, int> _mockFileModificationTimes;
+
+void initConfig() {
+  useCompactVMConfiguration();
+}
+
+/// Creates a new [DirectoryWatcher] that watches a temporary directory.
+///
+/// Normally, this will pause the schedule until the watcher is done scanning
+/// and is polling for changes. If you pass `false` for [waitForReady], it will
+/// not schedule this delay.
+DirectoryWatcher createWatcher({bool waitForReady}) {
+  _ensureSandbox();
+  _watcher = new DirectoryWatcher(_sandboxDir);
+
+  // Wait until the scan is finished so that we don't miss changes to files
+  // that could occur before the scan completes.
+  if (waitForReady != false) {
+    schedule(() => _watcher.ready);
+  }
+
+  currentSchedule.onComplete.schedule(() {
+    _nextEvent = 0;
+    _watcher = null;
+  }, "reset watcher");
+
+  return _watcher;
+}
+
+void expectEvent(ChangeType type, String path) {
+  // Immediately create the future. This ensures we don't register too late and
+  // drop the event before we receive it.
+  var future = _watcher.events.elementAt(_nextEvent++).then((event) {
+    expect(event, new _ChangeMatcher(type, path));
+  });
+
+  // Make sure the schedule is watching it in case it fails.
+  currentSchedule.wrapFuture(future);
+
+  // Schedule it so that later file modifications don't occur until after this
+  // event is received.
+  schedule(() => future);
+}
+
+void expectAddEvent(String path) {
+  expectEvent(ChangeType.ADD, pathos.join(_sandboxDir, path));
+}
+
+void expectModifyEvent(String path) {
+  expectEvent(ChangeType.MODIFY, pathos.join(_sandboxDir, path));
+}
+
+void expectRemoveEvent(String path) {
+  expectEvent(ChangeType.REMOVE, pathos.join(_sandboxDir, path));
+}
+
+/// Schedules writing a file in the sandbox at [path] with [contents].
+///
+/// If [contents] is omitted, creates an empty file. If [updatedModified] is
+/// `false`, the mock file modification time is not changed.
+void writeFile(String path, {String contents, bool updateModified}) {
+  if (contents == null) contents = "";
+  if (updateModified == null) updateModified = true;
+
+  _ensureSandbox();
+  schedule(() {
+    var fullPath = pathos.join(_sandboxDir, path);
+
+    // Create any needed subdirectories.
+    var dir = new Directory(pathos.dirname(fullPath));
+    if (!dir.existsSync()) {
+      dir.createSync(recursive: true);
+    }
+
+    new File(fullPath).writeAsStringSync(contents);
+
+    // Manually update the mock modification time for the file.
+    if (updateModified) {
+      var milliseconds = _mockFileModificationTimes.putIfAbsent(path, () => 0);
+      _mockFileModificationTimes[path]++;
+    }
+  });
+}
+
+/// Schedules deleting a file in the sandbox at [path].
+void deleteFile(String path) {
+  _ensureSandbox();
+  schedule(() {
+    new File(pathos.join(_sandboxDir, path)).deleteSync();
+  });
+}
+
+/// Schedules renaming a file in the sandbox from [from] to [to].
+///
+/// If [contents] is omitted, creates an empty file.
+void renameFile(String from, String to) {
+  _ensureSandbox();
+  schedule(() {
+    new File(pathos.join(_sandboxDir, from)).renameSync(
+        pathos.join(_sandboxDir, to));
+
+    // Manually update the mock modification time for the file.
+    var milliseconds = _mockFileModificationTimes.putIfAbsent(to, () => 0);
+    _mockFileModificationTimes[to]++;
+  });
+}
+
+/// Makes sure the sandbox directory has been created for this schedule.
+void _ensureSandbox() {
+  if (_sandboxDir != null) return;
+
+  var dir = new Directory("").createTempSync();
+  _sandboxDir = dir.path;
+
+  _mockFileModificationTimes = new Map<String, int>();
+  mockGetModificationTime((path) {
+    path = pathos.relative(path, from: _sandboxDir);
+
+    // Make sure we got a path in the sandbox.
+    assert(pathos.isRelative(path)  && !path.startsWith(".."));
+
+    return new DateTime.fromMillisecondsSinceEpoch(
+        _mockFileModificationTimes[path]);
+  });
+
+  currentSchedule.onComplete.schedule(() {
+    if (_sandboxDir != null) {
+      new Directory(_sandboxDir).deleteSync(recursive: true);
+      _sandboxDir = null;
+    }
+
+    _mockFileModificationTimes = null;
+    mockGetModificationTime(null);
+  }, "delete sandbox");
+}
+
+/// A [Matcher] for [WatchEvent]s.
+class _ChangeMatcher extends BaseMatcher {
+  /// The expected change.
+  final ChangeType type;
+
+  /// The expected path.
+  final String path;
+
+  _ChangeMatcher(this.type, this.path);
+
+  Description describe(Description description) {
+    description.add("$type $path");
+  }
+
+  bool matches(item, Map matchState) =>
+      item is WatchEvent && item.type == type && item.path == path;
+}