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driver.dart
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// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
import 'dart:async';
import 'dart:convert';
import 'dart:io';
import 'package:file/file.dart' as f;
import 'package:fuchsia_remote_debug_protocol/fuchsia_remote_debug_protocol.dart' as fuchsia;
import 'package:json_rpc_2/error_code.dart' as error_code;
import 'package:json_rpc_2/json_rpc_2.dart' as rpc;
import 'package:meta/meta.dart';
import 'package:path/path.dart' as p;
import 'package:vm_service_client/vm_service_client.dart';
import 'package:web_socket_channel/io.dart';
import '../common/diagnostics_tree.dart';
import '../common/error.dart';
import '../common/find.dart';
import '../common/frame_sync.dart';
import '../common/fuchsia_compat.dart';
import '../common/geometry.dart';
import '../common/gesture.dart';
import '../common/health.dart';
import '../common/message.dart';
import '../common/render_tree.dart';
import '../common/request_data.dart';
import '../common/semantics.dart';
import '../common/text.dart';
import 'common.dart';
import 'timeline.dart';
/// Timeline stream identifier.
enum TimelineStream {
/// A meta-identifier that instructs the Dart VM to record all streams.
all,
/// Marks events related to calls made via Dart's C API.
api,
/// Marks events from the Dart VM's JIT compiler.
compiler,
/// Marks events emitted using the `dart:developer` API.
dart,
/// Marks events from the Dart VM debugger.
debugger,
/// Marks events emitted using the `dart_tools_api.h` C API.
embedder,
/// Marks events from the garbage collector.
gc,
/// Marks events related to message passing between Dart isolates.
isolate,
/// Marks internal VM events.
vm,
}
const List<TimelineStream> _defaultStreams = <TimelineStream>[TimelineStream.all];
/// How long to wait before showing a message saying that
/// things seem to be taking a long time.
@visibleForTesting
const Duration kUnusuallyLongTimeout = Duration(seconds: 5);
/// The amount of time we wait prior to making the next attempt to connect to
/// the VM service.
const Duration _kPauseBetweenReconnectAttempts = Duration(seconds: 1);
// See https://github.com/dart-lang/sdk/blob/master/runtime/vm/timeline.cc#L32
String _timelineStreamsToString(List<TimelineStream> streams) {
final String contents = streams.map<String>((TimelineStream stream) {
switch (stream) {
case TimelineStream.all: return 'all';
case TimelineStream.api: return 'API';
case TimelineStream.compiler: return 'Compiler';
case TimelineStream.dart: return 'Dart';
case TimelineStream.debugger: return 'Debugger';
case TimelineStream.embedder: return 'Embedder';
case TimelineStream.gc: return 'GC';
case TimelineStream.isolate: return 'Isolate';
case TimelineStream.vm: return 'VM';
default:
throw 'Unknown timeline stream $stream';
}
}).join(', ');
return '[$contents]';
}
final Logger _log = Logger('FlutterDriver');
Future<T> _warnIfSlow<T>({
@required Future<T> future,
@required Duration timeout,
@required String message,
}) {
assert(future != null);
assert(timeout != null);
assert(message != null);
return future..timeout(timeout, onTimeout: () { _log.warning(message); return null; });
}
/// A convenient accessor to frequently used finders.
///
/// Examples:
///
/// driver.tap(find.text('Save'));
/// driver.scroll(find.byValueKey(42));
const CommonFinders find = CommonFinders._();
/// Computes a value.
///
/// If computation is asynchronous, the function may return a [Future].
///
/// See also [FlutterDriver.waitFor].
typedef EvaluatorFunction = dynamic Function();
/// Drives a Flutter Application running in another process.
class FlutterDriver {
/// Creates a driver that uses a connection provided by the given
/// [serviceClient], [_peer] and [appIsolate].
@visibleForTesting
FlutterDriver.connectedTo(
this.serviceClient,
this._peer,
this.appIsolate, {
bool printCommunication = false,
bool logCommunicationToFile = true,
}) : _printCommunication = printCommunication,
_logCommunicationToFile = logCommunicationToFile,
_driverId = _nextDriverId++;
static const String _flutterExtensionMethodName = 'ext.flutter.driver';
static const String _setVMTimelineFlagsMethodName = 'setVMTimelineFlags';
static const String _getVMTimelineMethodName = 'getVMTimeline';
static const String _clearVMTimelineMethodName = 'clearVMTimeline';
static const String _collectAllGarbageMethodName = '_collectAllGarbage';
static int _nextDriverId = 0;
// The additional blank line in the beginning is for _log.warning.
static const String _kDebugWarning = '''
┏╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍┓
┇ ⚠ THIS BENCHMARK IS BEING RUN IN DEBUG MODE ⚠ ┇
┡╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍╍┦
│ │
│ Numbers obtained from a benchmark while asserts are │
│ enabled will not accurately reflect the performance │
│ that will be experienced by end users using release ╎
│ builds. Benchmarks should be run using this command ┆
│ line: flutter drive --profile test_perf.dart ┊
│ ┊
└─────────────────────────────────────────────────╌┄┈ 🐢
''';
/// Connects to a Flutter application.
///
/// Resumes the application if it is currently paused (e.g. at a breakpoint).
///
/// `dartVmServiceUrl` is the URL to Dart observatory (a.k.a. VM service). If
/// not specified, the URL specified by the `VM_SERVICE_URL` environment
/// variable is used. One or the other must be specified.
///
/// `printCommunication` determines whether the command communication between
/// the test and the app should be printed to stdout.
///
/// `logCommunicationToFile` determines whether the command communication
/// between the test and the app should be logged to `flutter_driver_commands.log`.
///
/// `isolateNumber` determines the specific isolate to connect to.
/// If this is left as `null`, will connect to the first isolate found
/// running on `dartVmServiceUrl`.
///
/// `fuchsiaModuleTarget` specifies the pattern for determining which mod to
/// control. When running on a Fuchsia device, either this or the environment
/// variable `FUCHSIA_MODULE_TARGET` must be set (the environment variable is
/// treated as a substring pattern). This field will be ignored if
/// `isolateNumber` is set, as this is already enough information to connect
/// to an isolate.
///
/// The return value is a future. This method never times out, though it may
/// fail (completing with an error). A timeout can be applied by the caller
/// using [Future.timeout] if necessary.
static Future<FlutterDriver> connect({
String dartVmServiceUrl,
bool printCommunication = false,
bool logCommunicationToFile = true,
int isolateNumber,
Pattern fuchsiaModuleTarget,
}) async {
// If running on a Fuchsia device, connect to the first isolate whose name
// matches FUCHSIA_MODULE_TARGET.
//
// If the user has already supplied an isolate number/URL to the Dart VM
// service, then this won't be run as it is unnecessary.
if (Platform.isFuchsia && isolateNumber == null) {
// TODO(awdavies): Use something other than print. On fuchsia
// `stderr`/`stdout` appear to have issues working correctly.
flutterDriverLog.listen(print);
fuchsiaModuleTarget ??= Platform.environment['FUCHSIA_MODULE_TARGET'];
if (fuchsiaModuleTarget == null) {
throw DriverError(
'No Fuchsia module target has been specified.\n'
'Please make sure to specify the FUCHSIA_MODULE_TARGET '
'environment variable.'
);
}
final fuchsia.FuchsiaRemoteConnection fuchsiaConnection =
await FuchsiaCompat.connect();
final List<fuchsia.IsolateRef> refs =
await fuchsiaConnection.getMainIsolatesByPattern(fuchsiaModuleTarget);
final fuchsia.IsolateRef ref = refs.first;
isolateNumber = ref.number;
dartVmServiceUrl = ref.dartVm.uri.toString();
await fuchsiaConnection.stop();
FuchsiaCompat.cleanup();
}
dartVmServiceUrl ??= Platform.environment['VM_SERVICE_URL'];
if (dartVmServiceUrl == null) {
throw DriverError(
'Could not determine URL to connect to application.\n'
'Either the VM_SERVICE_URL environment variable should be set, or an explicit '
'URL should be provided to the FlutterDriver.connect() method.'
);
}
// Connect to Dart VM services
_log.info('Connecting to Flutter application at $dartVmServiceUrl');
final VMServiceClientConnection connection =
await vmServiceConnectFunction(dartVmServiceUrl);
final VMServiceClient client = connection.client;
final VM vm = await client.getVM();
final VMIsolateRef isolateRef = isolateNumber ==
null ? vm.isolates.first :
vm.isolates.firstWhere(
(VMIsolateRef isolate) => isolate.number == isolateNumber);
_log.trace('Isolate found with number: ${isolateRef.number}');
VMIsolate isolate = await isolateRef.loadRunnable();
// TODO(yjbanov): vm_service_client does not support "None" pause event yet.
// It is currently reported as null, but we cannot rely on it because
// eventually the event will be reported as a non-null object. For now,
// list all the events we know about. Later we'll check for "None" event
// explicitly.
//
// See: https://github.com/dart-lang/vm_service_client/issues/4
if (isolate.pauseEvent is! VMPauseStartEvent &&
isolate.pauseEvent is! VMPauseExitEvent &&
isolate.pauseEvent is! VMPauseBreakpointEvent &&
isolate.pauseEvent is! VMPauseExceptionEvent &&
isolate.pauseEvent is! VMPauseInterruptedEvent &&
isolate.pauseEvent is! VMResumeEvent) {
isolate = await isolateRef.loadRunnable();
}
final FlutterDriver driver = FlutterDriver.connectedTo(
client, connection.peer, isolate,
printCommunication: printCommunication,
logCommunicationToFile: logCommunicationToFile,
);
driver._dartVmReconnectUrl = dartVmServiceUrl;
// Attempts to resume the isolate, but does not crash if it fails because
// the isolate is already resumed. There could be a race with other tools,
// such as a debugger, any of which could have resumed the isolate.
Future<dynamic> resumeLeniently() {
_log.trace('Attempting to resume isolate');
return isolate.resume().catchError((dynamic e) {
const int vmMustBePausedCode = 101;
if (e is rpc.RpcException && e.code == vmMustBePausedCode) {
// No biggie; something else must have resumed the isolate
_log.warning(
'Attempted to resume an already resumed isolate. This may happen '
'when we lose a race with another tool (usually a debugger) that '
'is connected to the same isolate.'
);
} else {
// Failed to resume due to another reason. Fail hard.
throw e;
}
});
}
/// Waits for a signal from the VM service that the extension is registered.
/// Returns [_flutterExtensionMethodName]
Future<String> waitForServiceExtension() {
return isolate.onExtensionAdded.firstWhere((String extension) {
return extension == _flutterExtensionMethodName;
});
}
/// Tells the Dart VM Service to notify us about "Isolate" events.
///
/// This is a workaround for an issue in package:vm_service_client, which
/// subscribes to the "Isolate" stream lazily upon subscription, which
/// results in lost events.
///
/// Details: https://github.com/dart-lang/vm_service_client/issues/17
Future<void> enableIsolateStreams() async {
await connection.peer.sendRequest('streamListen', <String, String>{
'streamId': 'Isolate',
});
}
// Attempt to resume isolate if it was paused
if (isolate.pauseEvent is VMPauseStartEvent) {
_log.trace('Isolate is paused at start.');
// If the isolate is paused at the start, e.g. via the --start-paused
// option, then the VM service extension is not registered yet. Wait for
// it to be registered.
await enableIsolateStreams();
final Future<String> whenServiceExtensionReady = waitForServiceExtension();
final Future<dynamic> whenResumed = resumeLeniently();
await whenResumed;
_log.trace('Waiting for service extension');
// We will never receive the extension event if the user does not
// register it. If that happens, show a message but continue waiting.
await _warnIfSlow<String>(
future: whenServiceExtensionReady,
timeout: kUnusuallyLongTimeout,
message: 'Flutter Driver extension is taking a long time to become available. '
'Ensure your test app (often "lib/main.dart") imports '
'"package:flutter_driver/driver_extension.dart" and '
'calls enableFlutterDriverExtension() as the first call in main().',
);
} else if (isolate.pauseEvent is VMPauseExitEvent ||
isolate.pauseEvent is VMPauseBreakpointEvent ||
isolate.pauseEvent is VMPauseExceptionEvent ||
isolate.pauseEvent is VMPauseInterruptedEvent) {
// If the isolate is paused for any other reason, assume the extension is
// already there.
_log.trace('Isolate is paused mid-flight.');
await resumeLeniently();
} else if (isolate.pauseEvent is VMResumeEvent) {
_log.trace('Isolate is not paused. Assuming application is ready.');
} else {
_log.warning(
'Unknown pause event type ${isolate.pauseEvent.runtimeType}. '
'Assuming application is ready.'
);
}
// Invoked checkHealth and try to fix delays in the registration of Service
// extensions
Future<Health> checkHealth() async {
try {
// At this point the service extension must be installed. Verify it.
return await driver.checkHealth();
} on rpc.RpcException catch (e) {
if (e.code != error_code.METHOD_NOT_FOUND) {
rethrow;
}
_log.trace(
'Check Health failed, try to wait for the service extensions to be'
'registered.'
);
await enableIsolateStreams();
await waitForServiceExtension();
return driver.checkHealth();
}
}
final Health health = await checkHealth();
if (health.status != HealthStatus.ok) {
await client.close();
throw DriverError('Flutter application health check failed.');
}
_log.info('Connected to Flutter application.');
return driver;
}
/// The unique ID of this driver instance.
final int _driverId;
/// Client connected to the Dart VM running the Flutter application
///
/// You can use [VMServiceClient] to check VM version, flags and get
/// notified when a new isolate has been instantiated. That could be
/// useful if your application spawns multiple isolates that you
/// would like to instrument.
final VMServiceClient serviceClient;
/// JSON-RPC client useful for sending raw JSON requests.
rpc.Peer _peer;
String _dartVmReconnectUrl;
Future<void> _restorePeerConnectionIfNeeded() async {
if (!_peer.isClosed || _dartVmReconnectUrl == null) {
return;
}
_log.warning(
'Peer connection is closed! Trying to restore the connection...'
);
final String webSocketUrl = _getWebSocketUrl(_dartVmReconnectUrl);
final WebSocket ws = await WebSocket.connect(webSocketUrl);
ws.done.whenComplete(() => _checkCloseCode(ws));
_peer = rpc.Peer(
IOWebSocketChannel(ws).cast(),
onUnhandledError: _unhandledJsonRpcError,
)..listen();
}
/// The main isolate hosting the Flutter application.
///
/// If you used the [registerExtension] API to instrument your application,
/// you can use this [VMIsolate] to call these extension methods via
/// [invokeExtension].
final VMIsolate appIsolate;
/// Whether to print communication between host and app to `stdout`.
final bool _printCommunication;
/// Whether to log communication between host and app to `flutter_driver_commands.log`.
final bool _logCommunicationToFile;
Future<Map<String, dynamic>> _sendCommand(Command command) async {
Map<String, dynamic> response;
try {
final Map<String, String> serialized = command.serialize();
_logCommunication('>>> $serialized');
final Future<Map<String, dynamic>> future = appIsolate.invokeExtension(
_flutterExtensionMethodName,
serialized,
).then<Map<String, dynamic>>((Object value) => value);
response = await _warnIfSlow<Map<String, dynamic>>(
future: future,
timeout: command.timeout ?? kUnusuallyLongTimeout,
message: '${command.kind} message is taking a long time to complete...',
);
_logCommunication('<<< $response');
} catch (error, stackTrace) {
throw DriverError(
'Failed to fulfill ${command.runtimeType} due to remote error',
error,
stackTrace,
);
}
if (response['isError'])
throw DriverError('Error in Flutter application: ${response['response']}');
return response['response'];
}
void _logCommunication(String message) {
if (_printCommunication)
_log.info(message);
if (_logCommunicationToFile) {
final f.File file = fs.file(p.join(testOutputsDirectory, 'flutter_driver_commands_$_driverId.log'));
file.createSync(recursive: true); // no-op if file exists
file.writeAsStringSync('${DateTime.now()} $message\n', mode: f.FileMode.append, flush: true);
}
}
/// Checks the status of the Flutter Driver extension.
Future<Health> checkHealth({ Duration timeout }) async {
return Health.fromJson(await _sendCommand(GetHealth(timeout: timeout)));
}
/// Returns a dump of the render tree.
Future<RenderTree> getRenderTree({ Duration timeout }) async {
return RenderTree.fromJson(await _sendCommand(GetRenderTree(timeout: timeout)));
}
/// Taps at the center of the widget located by [finder].
Future<void> tap(SerializableFinder finder, { Duration timeout }) async {
await _sendCommand(Tap(finder, timeout: timeout));
}
/// Waits until [finder] locates the target.
Future<void> waitFor(SerializableFinder finder, { Duration timeout }) async {
await _sendCommand(WaitFor(finder, timeout: timeout));
}
/// Waits until [finder] can no longer locate the target.
Future<void> waitForAbsent(SerializableFinder finder, { Duration timeout }) async {
await _sendCommand(WaitForAbsent(finder, timeout: timeout));
}
/// Waits until there are no more transient callbacks in the queue.
///
/// Use this method when you need to wait for the moment when the application
/// becomes "stable", for example, prior to taking a [screenshot].
Future<void> waitUntilNoTransientCallbacks({ Duration timeout }) async {
await _sendCommand(WaitUntilNoTransientCallbacks(timeout: timeout));
}
/// Waits until the next [Window.onReportTimings] is called.
///
/// Use this method to wait for the first frame to be rasterized during the
/// app launch.
Future<void> waitUntilFirstFrameRasterized() async {
await _sendCommand(const WaitUntilFirstFrameRasterized());
}
Future<DriverOffset> _getOffset(SerializableFinder finder, OffsetType type, { Duration timeout }) async {
final GetOffset command = GetOffset(finder, type, timeout: timeout);
final GetOffsetResult result = GetOffsetResult.fromJson(await _sendCommand(command));
return DriverOffset(result.dx, result.dy);
}
/// Returns the point at the top left of the widget identified by `finder`.
///
/// The offset is expressed in logical pixels and can be translated to
/// device pixels via [Window.devicePixelRatio].
Future<DriverOffset> getTopLeft(SerializableFinder finder, { Duration timeout }) async {
return _getOffset(finder, OffsetType.topLeft, timeout: timeout);
}
/// Returns the point at the top right of the widget identified by `finder`.
///
/// The offset is expressed in logical pixels and can be translated to
/// device pixels via [Window.devicePixelRatio].
Future<DriverOffset> getTopRight(SerializableFinder finder, { Duration timeout }) async {
return _getOffset(finder, OffsetType.topRight, timeout: timeout);
}
/// Returns the point at the bottom left of the widget identified by `finder`.
///
/// The offset is expressed in logical pixels and can be translated to
/// device pixels via [Window.devicePixelRatio].
Future<DriverOffset> getBottomLeft(SerializableFinder finder, { Duration timeout }) async {
return _getOffset(finder, OffsetType.bottomLeft, timeout: timeout);
}
/// Returns the point at the bottom right of the widget identified by `finder`.
///
/// The offset is expressed in logical pixels and can be translated to
/// device pixels via [Window.devicePixelRatio].
Future<DriverOffset> getBottomRight(SerializableFinder finder, { Duration timeout }) async {
return _getOffset(finder, OffsetType.bottomRight, timeout: timeout);
}
/// Returns the point at the center of the widget identified by `finder`.
///
/// The offset is expressed in logical pixels and can be translated to
/// device pixels via [Window.devicePixelRatio].
Future<DriverOffset> getCenter(SerializableFinder finder, { Duration timeout }) async {
return _getOffset(finder, OffsetType.center, timeout: timeout);
}
/// Returns a JSON map of the [DiagnosticsNode] that is associated with the
/// [RenderObject] identified by `finder`.
///
/// The `subtreeDepth` argument controls how many layers of children will be
/// included in the result. It defaults to zero, which means that no children
/// of the [RenderObject] identified by `finder` will be part of the result.
///
/// The `includeProperties` argument controls whether properties of the
/// [DiagnosticsNode]s will be included in the result. It defaults to true.
///
/// [RenderObject]s are responsible for positioning, layout, and painting on
/// the screen, based on the configuration from a [Widget]. Callers that need
/// information about size or position should use this method.
///
/// A widget may indirectly create multiple [RenderObject]s, which each
/// implement some aspect of the widget configuration. A 1:1 relationship
/// should not be assumed.
///
/// See also:
///
/// * [getWidgetDiagnostics], which gets the [DiagnosticsNode] of a [Widget].
Future<Map<String, Object>> getRenderObjectDiagnostics(
SerializableFinder finder, {
int subtreeDepth = 0,
bool includeProperties = true,
Duration timeout,
}) async {
return _sendCommand(GetDiagnosticsTree(
finder,
DiagnosticsType.renderObject,
subtreeDepth: subtreeDepth,
includeProperties: includeProperties,
timeout: timeout,
));
}
/// Returns a JSON map of the [DiagnosticsNode] that is associated with the
/// [Widget] identified by `finder`.
///
/// The `subtreeDepth` argument controls how many layers of children will be
/// included in the result. It defaults to zero, which means that no children
/// of the [Widget] identified by `finder` will be part of the result.
///
/// The `includeProperties` argument controls whether properties of the
/// [DiagnosticsNode]s will be included in the result. It defaults to true.
///
/// [Widget]s describe configuration for the rendering tree. Individual
/// widgets may create multiple [RenderObject]s to actually layout and paint
/// the desired configuration.
///
/// See also:
///
/// * [getRenderObjectDiagnostics], which gets the [DiagnosticsNode] of a
/// [RenderObject].
Future<Map<String, Object>> getWidgetDiagnostics(
SerializableFinder finder, {
int subtreeDepth = 0,
bool includeProperties = true,
Duration timeout,
}) async {
return _sendCommand(GetDiagnosticsTree(
finder,
DiagnosticsType.renderObject,
subtreeDepth: subtreeDepth,
includeProperties: includeProperties,
timeout: timeout,
));
}
/// Tell the driver to perform a scrolling action.
///
/// A scrolling action begins with a "pointer down" event, which commonly maps
/// to finger press on the touch screen or mouse button press. A series of
/// "pointer move" events follow. The action is completed by a "pointer up"
/// event.
///
/// [dx] and [dy] specify the total offset for the entire scrolling action.
///
/// [duration] specifies the length of the action.
///
/// The move events are generated at a given [frequency] in Hz (or events per
/// second). It defaults to 60Hz.
Future<void> scroll(SerializableFinder finder, double dx, double dy, Duration duration, { int frequency = 60, Duration timeout }) async {
await _sendCommand(Scroll(finder, dx, dy, duration, frequency, timeout: timeout));
}
/// Scrolls the Scrollable ancestor of the widget located by [finder]
/// until the widget is completely visible.
///
/// If the widget located by [finder] is contained by a scrolling widget
/// that lazily creates its children, like [ListView] or [CustomScrollView],
/// then this method may fail because [finder] doesn't actually exist.
/// The [scrollUntilVisible] method can be used in this case.
Future<void> scrollIntoView(SerializableFinder finder, { double alignment = 0.0, Duration timeout }) async {
await _sendCommand(ScrollIntoView(finder, alignment: alignment, timeout: timeout));
}
/// Repeatedly [scroll] the widget located by [scrollable] by [dxScroll] and
/// [dyScroll] until [item] is visible, and then use [scrollIntoView] to
/// ensure the item's final position matches [alignment].
///
/// The [scrollable] must locate the scrolling widget that contains [item].
/// Typically `find.byType('ListView')` or `find.byType('CustomScrollView')`.
///
/// At least one of [dxScroll] and [dyScroll] must be non-zero.
///
/// If [item] is below the currently visible items, then specify a negative
/// value for [dyScroll] that's a small enough increment to expose [item]
/// without potentially scrolling it up and completely out of view. Similarly
/// if [item] is above, then specify a positive value for [dyScroll].
///
/// If [item] is to the right of the currently visible items, then
/// specify a negative value for [dxScroll] that's a small enough increment to
/// expose [item] without potentially scrolling it up and completely out of
/// view. Similarly if [item] is to the left, then specify a positive value
/// for [dyScroll].
///
/// The [timeout] value should be long enough to accommodate as many scrolls
/// as needed to bring an item into view. The default is to not time out.
Future<void> scrollUntilVisible(
SerializableFinder scrollable,
SerializableFinder item, {
double alignment = 0.0,
double dxScroll = 0.0,
double dyScroll = 0.0,
Duration timeout,
}) async {
assert(scrollable != null);
assert(item != null);
assert(alignment != null);
assert(dxScroll != null);
assert(dyScroll != null);
assert(dxScroll != 0.0 || dyScroll != 0.0);
// Kick off an (unawaited) waitFor that will complete when the item we're
// looking for finally scrolls onscreen. We add an initial pause to give it
// the chance to complete if the item is already onscreen; if not, scroll
// repeatedly until we either find the item or time out.
bool isVisible = false;
waitFor(item, timeout: timeout).then<void>((_) { isVisible = true; });
await Future<void>.delayed(const Duration(milliseconds: 500));
while (!isVisible) {
await scroll(scrollable, dxScroll, dyScroll, const Duration(milliseconds: 100));
await Future<void>.delayed(const Duration(milliseconds: 500));
}
return scrollIntoView(item, alignment: alignment);
}
/// Returns the text in the `Text` widget located by [finder].
Future<String> getText(SerializableFinder finder, { Duration timeout }) async {
return GetTextResult.fromJson(await _sendCommand(GetText(finder, timeout: timeout))).text;
}
/// Enters `text` into the currently focused text input, such as the
/// [EditableText] widget.
///
/// This method does not use the operating system keyboard to enter text.
/// Instead it emulates text entry by sending events identical to those sent
/// by the operating system keyboard (the "TextInputClient.updateEditingState"
/// method channel call).
///
/// Generally the behavior is dependent on the implementation of the widget
/// receiving the input. Usually, editable widgets, such as [EditableText] and
/// those built on top of it would replace the currently entered text with the
/// provided `text`.
///
/// It is assumed that the widget receiving text input is focused prior to
/// calling this method. Typically, a test would activate a widget, e.g. using
/// [tap], then call this method.
///
/// For this method to work, text emulation must be enabled (see
/// [setTextEntryEmulation]). Text emulation is enabled by default.
///
/// Example:
///
/// ```dart
/// test('enters text in a text field', () async {
/// var textField = find.byValueKey('enter-text-field');
/// await driver.tap(textField); // acquire focus
/// await driver.enterText('Hello!'); // enter text
/// await driver.waitFor(find.text('Hello!')); // verify text appears on UI
/// await driver.enterText('World!'); // enter another piece of text
/// await driver.waitFor(find.text('World!')); // verify new text appears
/// });
/// ```
Future<void> enterText(String text, { Duration timeout }) async {
await _sendCommand(EnterText(text, timeout: timeout));
}
/// Configures text entry emulation.
///
/// If `enabled` is true, enables text entry emulation via [enterText]. If
/// `enabled` is false, disables it. By default text entry emulation is
/// enabled.
///
/// When disabled, [enterText] will fail with a [DriverError]. When an
/// [EditableText] is focused, the operating system's configured keyboard
/// method is invoked, such as an on-screen keyboard on a phone or a tablet.
///
/// When enabled, the operating system's configured keyboard will not be
/// invoked when the widget is focused, as the [SystemChannels.textInput]
/// channel will be mocked out.
Future<void> setTextEntryEmulation({ @required bool enabled, Duration timeout }) async {
assert(enabled != null);
await _sendCommand(SetTextEntryEmulation(enabled, timeout: timeout));
}
/// Sends a string and returns a string.
///
/// This enables generic communication between the driver and the application.
/// It's expected that the application has registered a [DataHandler]
/// callback in [enableFlutterDriverExtension] that can successfully handle
/// these requests.
Future<String> requestData(String message, { Duration timeout }) async {
return RequestDataResult.fromJson(await _sendCommand(RequestData(message, timeout: timeout))).message;
}
/// Turns semantics on or off in the Flutter app under test.
///
/// Returns true when the call actually changed the state from on to off or
/// vice versa.
Future<bool> setSemantics(bool enabled, { Duration timeout }) async {
final SetSemanticsResult result = SetSemanticsResult.fromJson(await _sendCommand(SetSemantics(enabled, timeout: timeout)));
return result.changedState;
}
/// Retrieves the semantics node id for the object returned by `finder`, or
/// the nearest ancestor with a semantics node.
///
/// Throws an error if `finder` returns multiple elements or a semantics
/// node is not found.
///
/// Semantics must be enabled to use this method, either using a platform
/// specific shell command or [setSemantics].
Future<int> getSemanticsId(SerializableFinder finder, { Duration timeout }) async {
final Map<String, dynamic> jsonResponse = await _sendCommand(GetSemanticsId(finder, timeout: timeout));
final GetSemanticsIdResult result = GetSemanticsIdResult.fromJson(jsonResponse);
return result.id;
}
/// Take a screenshot.
///
/// The image will be returned as a PNG.
Future<List<int>> screenshot() async {
// HACK: this artificial delay here is to deal with a race between the
// driver script and the GPU thread. The issue is that driver API
// synchronizes with the framework based on transient callbacks, which
// are out of sync with the GPU thread. Here's the timeline of events
// in ASCII art:
//
// -------------------------------------------------------------------
// Without this delay:
// -------------------------------------------------------------------
// UI : <-- build -->
// GPU : <-- rasterize -->
// Gap : | random |
// Driver: <-- screenshot -->
//
// In the diagram above, the gap is the time between the last driver
// action taken, such as a `tap()`, and the subsequent call to
// `screenshot()`. The gap is random because it is determined by the
// unpredictable network communication between the driver process and
// the application. If this gap is too short, which it typically will
// be, the screenshot is taken before the GPU thread is done
// rasterizing the frame, so the screenshot of the previous frame is
// taken, which is wrong.
//
// -------------------------------------------------------------------
// With this delay, if we're lucky:
// -------------------------------------------------------------------
// UI : <-- build -->
// GPU : <-- rasterize -->
// Gap : | 2 seconds or more |
// Driver: <-- screenshot -->
//
// The two-second gap should be long enough for the GPU thread to
// finish rasterizing the frame, but not longer than necessary to keep
// driver tests as fast a possible.
//
// -------------------------------------------------------------------
// With this delay, if we're not lucky:
// -------------------------------------------------------------------
// UI : <-- build -->
// GPU : <-- rasterize randomly slow today -->
// Gap : | 2 seconds or more |
// Driver: <-- screenshot -->
//
// In practice, sometimes the device gets really busy for a while and
// even two seconds isn't enough, which means that this is still racy
// and a source of flakes.
await Future<void>.delayed(const Duration(seconds: 2));
final Map<String, dynamic> result = await _peer.sendRequest('_flutter.screenshot');
return base64.decode(result['screenshot']);
}
/// Returns the Flags set in the Dart VM as JSON.
///
/// See the complete documentation for [the `getFlagList` Dart VM service
/// method][getFlagList].
///
/// Example return value:
///
/// [
/// {
/// "name": "timeline_recorder",
/// "comment": "Select the timeline recorder used. Valid values: ring, endless, startup, and systrace.",
/// "modified": false,
/// "_flagType": "String",
/// "valueAsString": "ring"
/// },
/// ...
/// ]
///
/// [getFlagList]: https://github.com/dart-lang/sdk/blob/master/runtime/vm/service/service.md#getflaglist
Future<List<Map<String, dynamic>>> getVmFlags() async {
await _restorePeerConnectionIfNeeded();
final Map<String, dynamic> result = await _peer.sendRequest('getFlagList');
return result != null
? result['flags'].cast<Map<String,dynamic>>()
: const <Map<String, dynamic>>[];
}
/// Starts recording performance traces.
///
/// The `timeout` argument causes a warning to be displayed to the user if the
/// operation exceeds the specified timeout; it does not actually cancel the
/// operation.
Future<void> startTracing({
List<TimelineStream> streams = _defaultStreams,
Duration timeout = kUnusuallyLongTimeout,
}) async {
assert(streams != null && streams.isNotEmpty);
assert(timeout != null);
try {
await _warnIfSlow<void>(
future: _peer.sendRequest(_setVMTimelineFlagsMethodName, <String, String>{
'recordedStreams': _timelineStreamsToString(streams),
}),
timeout: timeout,
message: 'VM is taking an unusually long time to respond to being told to start tracing...',
);
} catch (error, stackTrace) {
throw DriverError(
'Failed to start tracing due to remote error',
error,
stackTrace,
);
}
}
/// Stops recording performance traces and downloads the timeline.
///
/// The `timeout` argument causes a warning to be displayed to the user if the
/// operation exceeds the specified timeout; it does not actually cancel the
/// operation.
Future<Timeline> stopTracingAndDownloadTimeline({
Duration timeout = kUnusuallyLongTimeout,
}) async {
assert(timeout != null);
try {
await _warnIfSlow<void>(
future: _peer.sendRequest(_setVMTimelineFlagsMethodName, <String, String>{'recordedStreams': '[]'}),
timeout: timeout,
message: 'VM is taking an unusually long time to respond to being told to stop tracing...',
);
return Timeline.fromJson(await _peer.sendRequest(_getVMTimelineMethodName));
} catch (error, stackTrace) {
throw DriverError(
'Failed to stop tracing due to remote error',
error,
stackTrace,
);
}
}
Future<bool> _isPrecompiledMode() async {
final List<Map<String, dynamic>> flags = await getVmFlags();
for(Map<String, dynamic> flag in flags) {
if (flag['name'] == 'precompiled_mode') {
return flag['valueAsString'] == 'true';
}
}
return false;
}
/// Runs [action] and outputs a performance trace for it.
///
/// Waits for the `Future` returned by [action] to complete prior to stopping
/// the trace.
///
/// This is merely a convenience wrapper on top of [startTracing] and
/// [stopTracingAndDownloadTimeline].
///
/// [streams] limits the recorded timeline event streams to only the ones
/// listed. By default, all streams are recorded.
///
/// If [retainPriorEvents] is true, retains events recorded prior to calling
/// [action]. Otherwise, prior events are cleared before calling [action]. By
/// default, prior events are cleared.
///
/// If this is run in debug mode, a warning message will be printed to suggest
/// running the benchmark in profile mode instead.
Future<Timeline> traceAction(
Future<dynamic> action(), {
List<TimelineStream> streams = _defaultStreams,
bool retainPriorEvents = false,
}) async {
if (!retainPriorEvents) {
await clearTimeline();
}
await startTracing(streams: streams);
await action();
if (!(await _isPrecompiledMode())) {
_log.warning(_kDebugWarning);
}
return stopTracingAndDownloadTimeline();
}
/// Clears all timeline events recorded up until now.
///
/// The `timeout` argument causes a warning to be displayed to the user if the
/// operation exceeds the specified timeout; it does not actually cancel the
/// operation.
Future<void> clearTimeline({
Duration timeout = kUnusuallyLongTimeout,
}) async {
assert(timeout != null);
try {
await _warnIfSlow<void>(
future: _peer.sendRequest(_clearVMTimelineMethodName, <String, String>{}),
timeout: timeout,
message: 'VM is taking an unusually long time to respond to being told to clear its timeline buffer...',
);
} catch (error, stackTrace) {
throw DriverError(
'Failed to clear event timeline due to remote error',
error,
stackTrace,
);
}
}