fix the stop command tests

packages/flutter_tools/lib/src/commands/daemon.dart

diff --git a/packages/flutter_tools/lib/src/commands/daemon.dart b/packages/flutter_tools/lib/src/commands/daemon.dart
index a98069d..99fe8f3 100644
--- a/packages/flutter_tools/lib/src/commands/daemon.dart
+++ b/packages/flutter_tools/lib/src/commands/daemon.dart
@@ -236,17 +236,17 @@
   }
 
   Future<dynamic> start(Map<String, dynamic> args) async {
-    if (args['deviceId'] is! String)
-      throw "A 'deviceId' is required";
+    if (args == null || args['deviceId'] is! String)
+      throw "deviceId is required";
     Device device = await _getDevice(args['deviceId']);
     if (device == null)
-      throw "A 'projectDirectory' is required";
+      throw "device '${args['deviceId']}' not found";
 
     if (args['projectDirectory'] is! String)
-      throw "A 'projectDirectory' is required";
+      throw "projectDirectory is required";
     String projectDirectory = args['projectDirectory'];
     if (!FileSystemEntity.isDirectorySync(projectDirectory))
-      throw "The '$projectDirectory' does not exist";
+      throw "'$projectDirectory' does not exist";
 
     // We change the current working directory for the duration of the `start` command.
     // TODO(devoncarew): Make flutter_tools work better with commands run from any directory.
@@ -280,17 +280,17 @@
   }
 
   Future<bool> stop(dynamic args) async {
-    if (args['deviceId'] is! String)
-      throw "A 'deviceId' is required";
+    if (args == null || args['deviceId'] is! String)
+      throw "deviceId is required";
     Device device = await _getDevice(args['deviceId']);
     if (device == null)
-      throw "A 'projectDirectory' is required";
+      throw "device '${args['deviceId']}' not found";
 
     if (args['projectDirectory'] is! String)
-      throw "A 'projectDirectory' is required";
+      throw "projectDirectory is required";
     String projectDirectory = args['projectDirectory'];
     if (!FileSystemEntity.isDirectorySync(projectDirectory))
-      throw "The '$projectDirectory' does not exist";
+      throw "'$projectDirectory' does not exist";
 
     Directory cwd = Directory.current;
     Directory.current = new Directory(projectDirectory);

packages/flutter_tools/test/daemon_test.dart

diff --git a/packages/flutter_tools/test/daemon_test.dart b/packages/flutter_tools/test/daemon_test.dart
index 5df8a08..9f986fc 100644
--- a/packages/flutter_tools/test/daemon_test.dart
+++ b/packages/flutter_tools/test/daemon_test.dart
@@ -12,7 +12,6 @@
 import 'package:flutter_tools/src/doctor.dart';
 import 'package:flutter_tools/src/globals.dart';
 import 'package:flutter_tools/src/ios/mac.dart';
-import 'package:mockito/mockito.dart';
 import 'package:test/test.dart';
 
 import 'src/context.dart';
@@ -97,7 +96,7 @@
       });
     });
 
-    _testUsingContext('daemon.stopAll', () async {
+    _testUsingContext('daemon.stop', () async {
       DaemonCommand command = new DaemonCommand();
       applyMocksToCommand(command);
 
@@ -110,16 +109,10 @@
         notifyingLogger: notifyingLogger
       );
 
-      MockDeviceStore mockDevices = command.devices;
-
-      when(mockDevices.android.stopApp(any)).thenReturn(true);
-      when(mockDevices.iOS.stopApp(any)).thenReturn(false);
-      when(mockDevices.iOSSimulator.stopApp(any)).thenReturn(false);
-
-      commands.add({'id': 0, 'method': 'app.stopAll'});
+      commands.add(<String, dynamic>{ 'id': 0, 'method': 'app.stop' });
       Map response = await responses.stream.where(_notEvent).first;
       expect(response['id'], 0);
-      expect(response['result'], true);
+      expect(response['error'], contains('deviceId is required'));
     });
 
     _testUsingContext('device.getDevices', () async {

packages/flutter_tools/test/src/context.dart

diff --git a/packages/flutter_tools/test/src/context.dart b/packages/flutter_tools/test/src/context.dart
index 3683b10..3ede26c 100644
--- a/packages/flutter_tools/test/src/context.dart
+++ b/packages/flutter_tools/test/src/context.dart
@@ -45,8 +45,11 @@
     if (!overrides.containsKey(SimControl))
       testContext[SimControl] = new MockSimControl();
 
-    if (!overrides.containsKey(OperatingSystemUtils))
-      testContext[OperatingSystemUtils] = new MockOperatingSystemUtils();
+    if (!overrides.containsKey(OperatingSystemUtils)) {
+      MockOperatingSystemUtils os = new MockOperatingSystemUtils();
+      when(os.isWindows).thenReturn(false);
+      testContext[OperatingSystemUtils] = os;
+    }
 
     if (!overrides.containsKey(IOSSimulatorUtils)) {
       MockIOSSimulatorUtils mock = new MockIOSSimulatorUtils();

packages/flutter_tools/test/stop_test.dart

diff --git a/packages/flutter_tools/test/stop_test.dart b/packages/flutter_tools/test/stop_test.dart
index 82b733e..112a9fc 100644
--- a/packages/flutter_tools/test/stop_test.dart
+++ b/packages/flutter_tools/test/stop_test.dart
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'dart:async';
+
 import 'package:flutter_tools/src/commands/stop.dart';
 import 'package:mockito/mockito.dart';
 import 'package:test/test.dart';
@@ -17,12 +19,9 @@
     testUsingContext('returns 0 when Android is connected and ready to be stopped', () {
       StopCommand command = new StopCommand();
       applyMocksToCommand(command);
-      MockDeviceStore mockDevices = command.devices;
-
-      when(mockDevices.android.stopApp(any)).thenReturn(true);
-      when(mockDevices.iOS.stopApp(any)).thenReturn(false);
-      when(mockDevices.iOSSimulator.stopApp(any)).thenReturn(false);
-
+      MockAndroidDevice device = new MockAndroidDevice();
+      when(device.stopApp(any)).thenReturn(new Future.value(true));
+      testDeviceManager.addDevice(device);
       return createTestCommandRunner(command).run(['stop']).then((int code) {
         expect(code, equals(0));
       });
@@ -31,11 +30,9 @@
     testUsingContext('returns 0 when iOS is connected and ready to be stopped', () {
       StopCommand command = new StopCommand();
       applyMocksToCommand(command);
-      MockDeviceStore mockDevices = command.devices;
-
-      when(mockDevices.android.stopApp(any)).thenReturn(false);
-      when(mockDevices.iOS.stopApp(any)).thenReturn(true);
-      when(mockDevices.iOSSimulator.stopApp(any)).thenReturn(false);
+      MockIOSDevice device = new MockIOSDevice();
+      when(device.stopApp(any)).thenReturn(new Future.value(true));
+      testDeviceManager.addDevice(device);
 
       return createTestCommandRunner(command).run(['stop']).then((int code) {
         expect(code, equals(0));