integration_ui test is flaky #19826
Description
It failed on #19785 with (log):
2018-07-25T16:31:16.428793: stdout: [ ] /Users/flutter/.cocoon/flutter/bin/cache/dart-sdk/bin/dart /Users/flutter/.cocoon/flutter/dev/integration_tests/ui/test_driver/screenshot_test.dart --packages=/Users/flutter/.cocoon/flutter/dev/integration_tests/ui/.packages -rexpanded --preview-dart-2
2018-07-25T16:31:19.566709: stdout: [+3137 ms] 00:00 �[32m+0�[0m: FlutterDriver (setUpAll)�[0m
2018-07-25T16:31:19.610419: stderr: [ +42 ms] [info ] FlutterDriver: Connecting to Flutter application at http://127.0.0.1:55437/
2018-07-25T16:31:20.253804: stderr: [ +644 ms] [trace] FlutterDriver: Isolate found with number: 665842189
2018-07-25T16:31:20.511030: stderr: [ +257 ms] [trace] FlutterDriver: Isolate is paused at start.
2018-07-25T16:31:20.529121: stderr: [ +18 ms] [trace] FlutterDriver: Attempting to resume isolate
2018-07-25T16:31:20.546549: stderr: [ +17 ms] [trace] FlutterDriver: Waiting for service extension
2018-07-25T16:31:22.430088: stderr: [+1883 ms] [info ] FlutterDriver: Connected to Flutter application.
2018-07-25T16:31:22.443205: stdout: [ +13 ms] 00:02 �[32m+0�[0m: FlutterDriver should take screenshot�[0m
2018-07-25T16:31:30.452638: stdout: [+8009 ms] 00:10 �[32m+0�[0m�[31m -1�[0m: FlutterDriver should take screenshot �[1m�[31m[E]�[0m�[0m
2018-07-25T16:31:30.454410: stdout: [ +1 ms] JSON-RPC error -32602 (invalid parameters): Invalid params
2018-07-25T16:31:30.479301: stdout: [ +24 ms] package:json_rpc_2/src/client.dart 110:64 Client.sendRequest
2018-07-25T16:31:30.480184: stdout: [ ] package:json_rpc_2/src/peer.dart 68:15 Peer.sendRequest
stdout: [ ] package:flutter_driver/src/driver/driver.dart 627:53 FlutterDriver.screenshot
stdout: [ ] ===== asynchronous gap ===========================
2018-07-25T16:31:30.480330: stdout: [ ] dart:async/zone.dart 1055:19 _CustomZone.registerUnaryCallback
stdout: [ ] dart:async/runtime/libasync_patch.dart 77:23 _asyncThenWrapperHelper
2018-07-25T16:31:30.481558: stdout: [ ] package:flutter_driver/src/driver/driver.dart FlutterDriver.screenshot
stdout: [ ] test_driver/screenshot_test.dart 32:57 main..
stdout: [ ] ===== asynchronous gap ===========================
stdout: [ ] dart:async/zone.dart 1055:19 _CustomZone.registerUnaryCallback
stdout: [ ] dart:async/runtime/libasync_patch.dart 77:23 _asyncThenWrapperHelper
stdout: [ ] test_driver/screenshot_test.dart main..
stdout: [ ] package:test/src/backend/declarer.dart 161:27 Declarer.test...
stdout: [ ] ===== asynchronous gap ===========================
stdout: [ ] dart:async/zone.dart 1055:19 _CustomZone.registerUnaryCallback
stdout: [ ] dart:async/runtime/libasync_patch.dart 77:23 _asyncThenWrapperHelper
stdout: [ ] package:test/src/backend/declarer.dart Declarer.test...
stdout: [ ] package:test/src/backend/invoker.dart 249:15 Invoker.waitForOutstandingCallbacks.
stdout: [ ] ===== asynchronous gap ===========================
stdout: [ ] dart:async/zone.dart 1047:19 _CustomZone.registerCallback
stdout: [ ] dart:async/zone.dart 964:22 _CustomZone.bindCallbackGuarded
stdout: [ ] dart:async/timer.dart 52:45 new Timer
stdout: [ ] dart:async/timer.dart 87:9 Timer.run
stdout: [ ] dart:async/future.dart 172:11 new Future
stdout: [ ] package:test/src/backend/invoker.dart 402:15 Invoker._onRun...
stdout: [ ] 00:10 �[32m+0�[0m�[31m -1�[0m: FlutterDriver (tearDownAll)�[0m
2018-07-25T16:31:30.514731: stdout: [ +33 ms] 00:10 �[32m+0�[0m�[31m -1�[0m: �[31mSome tests failed.�[0m
2018-07-25T16:31:30.530842: stderr: [ +14 ms] Unhandled exception:
stderr: [ ] Dummy exception to set exit code.
stderr: [ ] #0 _rootHandleUncaughtError. (dart:async/zone.dart:1114:29)
stderr: [ ] #1 _microtaskLoop (dart:async/schedule_microtask.dart:41:21)
stderr: [ ] #2 _startMicrotaskLoop (dart:async/schedule_microtask.dart:50:5)
stderr: [ ] #3 _Timer._runTimers (dart:isolate/runtime/libtimer_impl.dart:391:30)
stderr: [ ] #4 _Timer._handleMessage (dart:isolate/runtime/libtimer_impl.dart:416:5)
stderr: [ ] #5 _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:165:12)
2018-07-25T16:31:30.583529: stdout: [ +53 ms] Stopping application instance.
2018-07-25T16:31:30.583612: stdout: [ ] Stopping application.
2018-07-25T16:31:30.584382: stdout: [ ] /Volumes/DevicelabAndroid/sdk/platform-tools/adb -s ZY2245H6ZS shell am force-stop com.yourcompany.integration_ui
2018-07-25T16:31:31.542652: stdout: [ +958 ms] "flutter drive" took 56,459ms.
2018-07-25T16:31:31.545161: stderr: Driver tests failed: 255
2018-07-25T16:31:31.545260: stderr:
2018-07-25T16:31:31.545769: stderr: #0 throwToolExit (package:flutter_tools/src/base/common.dart:26:3)
stderr: #1 _runTests (package:flutter_tools/src/commands/drive.dart:303:5)
stderr:
2018-07-25T16:31:31.545895: stderr: #2 DriveCommand.runCommand (package:flutter_tools/src/commands/drive.dart:126:23)
stderr:
stderr: #3 FlutterCommand.verifyThenRunCommand (package:flutter_tools/src/runner/flutter_command.dart:347:18)
stderr:
stderr: #4 FlutterCommand.run. (package:flutter_tools/src/runner/flutter_command.dart:282:33)
stderr:
2018-07-25T16:31:31.545988: stderr: #5 AppContext.run. (package:flutter_tools/src/base/context.dart:142:29)
stderr:
stderr: #6 _rootRun (dart:async/zone.dart:1126:13)
stderr: #7 _CustomZone.run (dart:async/zone.dart:1023:19)
stderr: #8 _runZoned (dart:async/zone.dart:1518:10)
stderr: #9 runZoned (dart:async/zone.dart:1465:12)
2018-07-25T16:31:31.546073: stderr: #10 AppContext.run (package:flutter_tools/src/base/context.dart:141:18)
stderr:
stderr: #11 FlutterCommand.run (package:flutter_tools/src/runner/flutter_command.dart:273:20)
stderr: #12 CommandRunner.runCommand (package:args/command_runner.dart:194:27)
stderr:
2018-07-25T16:31:31.546175: stderr: #13 FlutterCommandRunner.runCommand. (package:flutter_tools/src/runner/flutter_command_runner.dart:346:21)
stderr:
stderr: #14 AppContext.run. (package:flutter_tools/src/base/context.dart:142:29)
stderr:
stderr: #15 _rootRun (dart:async/zone.dart:1126:13)
stderr: #16 _CustomZone.run (dart:async/zone.dart:1023:19)
2018-07-25T16:31:31.546262: stderr: #17 _runZoned (dart:async/zone.dart:1518:10)
stderr: #18 runZoned (dart:async/zone.dart:1465:12)
stderr: #19 AppContext.run (package:flutter_tools/src/base/context.dart:141:18)
stderr:
stderr: #20 FlutterCommandRunner.runCommand (package:flutter_tools/src/runner/flutter_command_runner.dart:302:19)
stderr:
stderr: #21 CommandRunner.run. (package:args/command_runner.dart:109:29)
2018-07-25T16:31:31.546348: stderr: #22 new Future.sync (dart:async/future.dart:222:31)
stderr: #23 CommandRunner.run (package:args/command_runner.dart:109:11)
stderr: #24 FlutterCommandRunner.run (package:flutter_tools/src/runner/flutter_command_runner.dart:211:18)
stderr: #25 run. (package:flutter_tools/runner.dart:59:20)
stderr:
2018-07-25T16:31:31.546440: stderr: #26 AppContext.run. (package:flutter_tools/src/base/context.dart:142:29)
stderr:
stderr: #27 _rootRun (dart:async/zone.dart:1126:13)
stderr: #28 _CustomZone.run (dart:async/zone.dart:1023:19)
stderr: #29 _runZoned (dart:async/zone.dart:1518:10)
stderr: #30 runZoned (dart:async/zone.dart:1465:12)
2018-07-25T16:31:31.546526: stderr: #31 AppContext.run (package:flutter_tools/src/base/context.dart:141:18)
stderr:
stderr: #32 runInContext (package:flutter_tools/src/context_runner.dart:42:24)
stderr:
stderr: #33 run (package:flutter_tools/runner.dart:50:10)
stderr: #34 main (package:flutter_tools/executable.dart:51:9)
2018-07-25T16:31:31.546653: stderr:
stderr: #35 main (file:///Users/flutter/.cocoon/flutter/packages/flutter_tools/bin/flutter_tools.dart:8:3)
stderr: #36 _startIsolate. (dart:isolate/runtime/libisolate_patch.dart:277:32)
stderr: #37 _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:165:12)
stderr:
stderr:
2018-07-25T16:31:31.572344: exitcode: 255
2018-07-25T16:31:31.590162: Task failed: Executable failed with exit code 255.2018-07-25T16:31:31.590267:
Stack trace:
2018-07-25T16:31:31.626372: package:flutter_devicelab/framework/utils.dart 77:3 fail
package:flutter_devicelab/framework/utils.dart 283:5 exec
===== asynchronous gap ===========================
dart:async _AsyncAwaitCompleter.completeError
package:flutter_devicelab/framework/utils.dart exec
===== asynchronous gap ===========================
dart:async _asyncThenWrapperHelper
package:flutter_devicelab/framework/utils.dart exec
package:flutter_devicelab/framework/utils.dart 331:10 flutter
package:flutter_devicelab/tasks/integration_ui.dart 32:13 runEndToEndTests.
===== asynchronous gap ===========================
dart:async _asyncThenWrapperHelper
package:flutter_devicelab/tasks/integration_ui.dart runEndToEndTests.
package:flutter_devicelab/framework/utils.dart 369:24 inDirectory
===== asynchronous gap ===========================
dart:async _asyncThenWrapperHelper
package:flutter_devicelab/tasks/integration_ui.dart runEndToEndTests
package:flutter_devicelab/framework/framework.dart 125:32 _TaskRunner._performTask.
It previously flaked on #19721 with (log):
2018-07-25T11:43:50.558193: stdout: [ ] /Users/flutter/.cocoon/flutter/bin/cache/dart-sdk/bin/dart /Users/flutter/.cocoon/flutter/dev/integration_tests/ui/test_driver/screenshot_test.dart --packages=/Users/flutter/.cocoon/flutter/dev/integration_tests/ui/.packages -rexpanded --preview-dart-2
2018-07-25T11:43:53.776589: stdout: [+3218 ms] 00:00 �[32m+0�[0m: FlutterDriver (setUpAll)�[0m
2018-07-25T11:43:53.825194: stderr: [ +47 ms] [info ] FlutterDriver: Connecting to Flutter application at http://127.0.0.1:58659/
2018-07-25T11:43:54.477321: stdout: [ +653 ms] 00:00 �[32m+0�[0m�[31m -1�[0m: FlutterDriver (setUpAll) �[1m�[31m[E]�[0m�[0m
2018-07-25T11:43:54.477980: stdout: [ ] Bad state: No element
2018-07-25T11:43:54.502289: stdout: [ +23 ms] dart:core/runtime/libarray.dart 165:5 List.first
2018-07-25T11:43:54.502688: stdout: [ ] package:flutter_driver/src/driver/driver.dart 181:28 FlutterDriver.connect
stdout: [ ] ===== asynchronous gap ===========================
stdout: [ ] dart:async/future_impl.dart 22:43 _Completer.completeError
stdout: [ ] dart:async/runtime/libasync_patch.dart 40:18 _AsyncAwaitCompleter.completeError
stdout: [ ] package:flutter_driver/src/driver/driver.dart FlutterDriver.connect
stdout: [ ] ===== asynchronous gap ===========================
stdout: [ ] dart:async/zone.dart 1055:19 _CustomZone.registerUnaryCallback
stdout: [ ] dart:async/runtime/libasync_patch.dart 77:23 _asyncThenWrapperHelper
stdout: [ ] package:flutter_driver/src/driver/driver.dart FlutterDriver.connect
stdout: [ ] test_driver/screenshot_test.dart 14:36 main..
stdout: [ ] ===== asynchronous gap ===========================
stdout: [ ] dart:async/zone.dart 1055:19 _CustomZone.registerUnaryCallback
stdout: [ ] dart:async/zone.dart 969:22 _CustomZone.bindUnaryCallbackGuarded
stdout: [ ] dart:async/future.dart 522:34 Future.doWhile
stdout: [ ] dart:async/future.dart 482:12 Future.forEach
stdout: [ ] package:test/src/backend/declarer.dart 272:36 Declarer._setUpAll..
stdout: [ ] dart:async/zone.dart 1126:13 _rootRun
stdout: [ ] dart:async/zone.dart 1023:19 _CustomZone.run
stdout: [ ] dart:async/zone.dart 1518:10 _runZoned
2018-07-25T11:43:54.502804: stdout: [ ] dart:async/zone.dart 1465:12 runZoned
stdout: [ ] package:test/src/backend/declarer.dart 272:14 Declarer._setUpAll.
stdout: [ ] package:test/src/backend/invoker.dart 403:25 Invoker._onRun....
2018-07-25T11:43:54.502889: stdout: [ ] ===== asynchronous gap ===========================
stdout: [ ] dart:async/zone.dart 1047:19 _CustomZone.registerCallback
stdout: [ ] dart:async/zone.dart 964:22 _CustomZone.bindCallbackGuarded
stdout: [ ] dart:async/timer.dart 52:45 new Timer
2018-07-25T11:43:54.502988: stdout: [ ] dart:async/timer.dart 87:9 Timer.run
2018-07-25T11:43:54.503066: stdout: [ ] dart:async/future.dart 172:11 new Future
stdout: [ ] package:test/src/backend/invoker.dart 402:15 Invoker._onRun...
2018-07-25T11:43:54.505365: stdout: [ +2 ms] 00:00 �[32m+0�[0m�[31m -1�[0m: FlutterDriver (tearDownAll)�[0m
2018-07-25T11:43:54.531740: stdout: [ +26 ms] 00:00 �[32m+0�[0m�[31m -2�[0m: FlutterDriver (tearDownAll) �[1m�[31m[E]�[0m�[0m
2018-07-25T11:43:54.537536: stdout: [ +5 ms] NoSuchMethodError: The method 'close' was called on null.
2018-07-25T11:43:54.537700: stdout: [ ] Receiver: null
stdout: [ ] Tried calling: close()
2018-07-25T11:43:54.544266: stdout: [ +5 ms] dart:core/runtime/libobject_patch.dart 46:5 Object.noSuchMethod
stdout: [ ] test_driver/screenshot_test.dart 18:20 main..
stdout: [ ] ===== asynchronous gap ===========================
stdout: [ ] dart:async/future_impl.dart 22:43 _Completer.completeError
stdout: [ ] dart:async/runtime/libasync_patch.dart 43:20 _AsyncAwaitCompleter.completeError.
stdout: [ ] package:stack_trace/src/stack_zone_specification.dart 209:15 StackZoneSpecification._run
stdout: [ ] package:stack_trace/src/stack_zone_specification.dart 119:48 StackZoneSpecification._registerCallback.
stdout: [ ] dart:async/zone.dart 1122:38 _rootRun
stdout: [ ] dart:async/zone.dart 1023:19 _CustomZone.run
stdout: [ ] dart:async/zone.dart 925:7 _CustomZone.runGuarded
stdout: [ ] dart:async/zone.dart 965:23 _CustomZone.bindCallbackGuarded.
stdout: [ ] package:stack_trace/src/stack_zone_specification.dart 209:15 StackZoneSpecification._run
stdout: [ ] package:stack_trace/src/stack_zone_specification.dart 119:48 StackZoneSpecification._registerCallback.
2018-07-25T11:43:54.544574: stdout: [ ] dart:async/zone.dart 1126:13 _rootRun
stdout: [ ] dart:async/zone.dart 1023:19 _CustomZone.run
2018-07-25T11:43:54.544690: stdout: [ ] dart:async/zone.dart 925:7 _CustomZone.runGuarded
2018-07-25T11:43:54.544830: stdout: [ ] dart:async/zone.dart 965:23 _CustomZone.bindCallbackGuarded.
2018-07-25T11:43:54.545441: stdout: [ ] dart:async/schedule_microtask.dart 41:21 _microtaskLoop
stdout: [ ] dart:async/schedule_microtask.dart 50:5 _startMicrotaskLoop
stdout: [ ] dart:isolate/runtime/libtimer_impl.dart 391:30 _Timer._runTimers
stdout: [ ] dart:isolate/runtime/libtimer_impl.dart 416:5 _Timer._handleMessage
stdout: [ ] dart:isolate/runtime/libisolate_patch.dart 165:12 _RawReceivePortImpl._handleMessage
stdout: [ ] ===== asynchronous gap ===========================
2018-07-25T11:43:54.546005: stdout: [ ] dart:async/zone.dart 1047:19 _CustomZone.registerCallback
stdout: [ ] dart:async/zone.dart 964:22 _CustomZone.bindCallbackGuarded
stdout: [ ] dart:async/schedule_microtask.dart 147:47 scheduleMicrotask
stdout: [ ] dart:async/runtime/libasync_patch.dart 42:7 _AsyncAwaitCompleter.completeError
stdout: [ ] test_driver/screenshot_test.dart main..
stdout: [ ] ===== asynchronous gap ===========================
stdout: [ ] dart:async/zone.dart 1047:19 _CustomZone.registerCallback
stdout: [ ] dart:async/zone.dart 964:22 _CustomZone.bindCallbackGuarded
2018-07-25T11:43:54.546131: stdout: [ ] dart:async/timer.dart 52:45 new Timer
stdout: [ ] dart:async/timer.dart 87:9 Timer.run
stdout: [ ] dart:async/future.dart 172:11 new Future
2018-07-25T11:43:54.546292: stdout: [ ] package:test/src/backend/invoker.dart 402:15 Invoker._onRun...
2018-07-25T11:43:54.558615: stdout: [ +12 ms] 00:00 �[32m+0�[0m�[31m -2�[0m: �[31mSome tests failed.�[0m
2018-07-25T11:43:54.560950: stderr: [ +2 ms] Unhandled exception:
2018-07-25T11:43:54.561593: stderr: [ ] Dummy exception to set exit code.
stderr: [ ] #0 _rootHandleUncaughtError. (dart:async/zone.dart:1114:29)
stderr: [ ] #1 _microtaskLoop (dart:async/schedule_microtask.dart:41:21)
stderr: [ ] #2 _startMicrotaskLoop (dart:async/schedule_microtask.dart:50:5)
stderr: [ ] #3 _Timer._runTimers (dart:isolate/runtime/libtimer_impl.dart:391:30)
stderr: [ ] #4 _Timer._handleMessage (dart:isolate/runtime/libtimer_impl.dart:416:5)
stderr: [ ] #5 _RawReceivePortImpl._handleMessage (dart:isolate/runtime/libisolate_patch.dart:165:12)
Also flaked on #19565 with(log):
2018-07-20T16:12:55.934015: stdout: [ ] /Users/flutter/.cocoon/flutter/bin/cache/dart-sdk/bin/dart /Users/flutter/.cocoon/flutter/dev/integration_tests/ui/test_driver/screenshot_test.dart --packages=/Users/flutter/.cocoon/flutter/dev/integration_tests/ui/.packages -rexpanded --preview-dart-2
2018-07-20T16:12:59.353712: stdout: [+3419 ms] 00:00 �[32m+0�[0m: FlutterDriver (setUpAll)�[0m
2018-07-20T16:12:59.405960: stderr: [ +51 ms] [info ] FlutterDriver: Connecting to Flutter application at http://127.0.0.1:53932/
2018-07-20T16:13:00.062502: stdout: [ +657 ms] 00:00 �[32m+0�[0m�[31m -1�[0m: FlutterDriver (setUpAll) �[1m�[31m[E]�[0m�[0m
2018-07-20T16:13:00.063222: stdout: [ ] Bad state: No element
2018-07-20T16:13:00.089837: stdout: [ +26 ms] dart:core/runtime/libarray.dart 165:5 List.first
2018-07-20T16:13:00.090789: stdout: [ ] package:flutter_driver/src/driver/driver.dart 181:28 FlutterDriver.connect
stdout: [ ] ===== asynchronous gap ===========================
stdout: [ ] dart:async/future_impl.dart 22:43 _Completer.completeError
stdout: [ ] dart:async/runtime/libasync_patch.dart 40:18 _AsyncAwaitCompleter.completeError
stdout: [ ] package:flutter_driver/src/driver/driver.dart FlutterDriver.connect
stdout: [ ] ===== asynchronous gap ===========================
stdout: [ ] dart:async/zone.dart 1055:19 _CustomZone.registerUnaryCallback
stdout: [ ] dart:async/runtime/libasync_patch.dart 77:23 _asyncThenWrapperHelper
stdout: [ ] package:flutter_driver/src/driver/driver.dart FlutterDriver.connect
stdout: [ ] test_driver/screenshot_test.dart 14:36 main..
stdout: [ ] ===== asynchronous gap ===========================
stdout: [ ] dart:async/zone.dart 1055:19 _CustomZone.registerUnaryCallback
stdout: [ ] dart:async/zone.dart 969:22 _CustomZone.bindUnaryCallbackGuarded
stdout: [ ] dart:async/future.dart 522:34 Future.doWhile
2018-07-20T16:13:00.091398: stdout: [ ] dart:async/future.dart 482:12 Future.forEach
stdout: [ ] package:test/src/backend/declarer.dart 272:36 Declarer._setUpAll..
2018-07-20T16:13:00.092343: stdout: [ ] dart:async/zone.dart 1126:13 _rootRun
stdout: [ ] dart:async/zone.dart 1023:19 _CustomZone.run
stdout: [ ] dart:async/zone.dart 1518:10 _runZoned
2018-07-20T16:13:00.092460: stdout: [ ] dart:async/zone.dart 1465:12 runZoned
2018-07-20T16:13:00.093053: stdout: [ ] package:test/src/backend/declarer.dart 272:14 Declarer._setUpAll.
stdout: [ ] package:test/src/backend/invoker.dart 403:25 Invoker._onRun....
stdout: [ ] ===== asynchronous gap ===========================
stdout: [ ] dart:async/zone.dart 1047:19 _CustomZone.registerCallback
stdout: [ ] dart:async/zone.dart 964:22 _CustomZone.bindCallbackGuarded
stdout: [ ] dart:async/timer.dart 52:45 new Timer
stdout: [ ] dart:async/timer.dart 87:9 Timer.run
stdout: [ ] dart:async/future.dart 172:11 new Future
stdout: [ ] package:test/src/backend/invoker.dart 402:15 Invoker._onRun...
2018-07-20T16:13:00.095890: stdout: [ +4 ms] 00:00 �[32m+0�[0m�[31m -1�[0m: FlutterDriver (tearDownAll)�[0m
2018-07-20T16:13:00.111793: stdout: [ +15 ms] 00:00 �[32m+0�[0m�[31m -2�[0m: FlutterDriver (tearDownAll) �[1m�[31m[E]�[0m�[0m
2018-07-20T16:13:00.118202: stdout: [ +6 ms] NoSuchMethodError: The method 'close' was called on null.
2018-07-20T16:13:00.118469: stdout: [ ] Receiver: null
stdout: [ ] Tried calling: close()
2018-07-20T16:13:00.125533: stdout: [ +7 ms] dart:core/runtime/libobject_patch.dart 46:5 Object.noSuchMethod
2018-07-20T16:13:00.125709: stdout: [ ] test_driver/screenshot_test.dart 18:20 main..
2018-07-20T16:13:00.127355: stdout: [ ] ===== asynchronous gap ===========================
stdout: [ ] dart:async/future_impl.dart 22:43 _Completer.completeError
stdout: [ ] dart:async/runtime/libasync_patch.dart 43:20 _AsyncAwaitCompleter.completeError.
stdout: [ ] package:stack_trace/src/stack_zone_specification.dart 209:15 StackZoneSpecification._run
stdout: [ ] package:stack_trace/src/stack_zone_specification.dart 119:48 StackZoneSpecification._registerCallback.
stdout: [ ] dart:async/zone.dart 1122:38 _rootRun
stdout: [ ] dart:async/zone.dart 1023:19 _CustomZone.run
stdout: [ ] dart:async/zone.dart 925:7 _CustomZone.runGuarded
stdout: [ ] dart:async/zone.dart 965:23 _CustomZone.bindCallbackGuarded.
stdout: [ ] package:stack_trace/src/stack_zone_specification.dart 209:15 StackZoneSpecification._run
stdout: [ ] package:stack_trace/src/stack_zone_specification.dart 119:48 StackZoneSpecification._registerCallback.
stdout: [ ] dart:async/zone.dart 1126:13 _rootRun
stdout: [ ] dart:async/zone.dart 1023:19 _CustomZone.run
stdout: [ ] dart:async/zone.dart 925:7 _CustomZone.runGuarded
stdout: [ ] dart:async/zone.dart 965:23 _CustomZone.bindCallbackGuarded.
stdout: [ ] dart:async/schedule_microtask.dart 41:21 _microtaskLoop
stdout: [ ] dart:async/schedule_microtask.dart 50:5 _startMicrotaskLoop
stdout: [ ] dart:isolate/runtime/libtimer_impl.dart 391:30 _Timer._runTimers
stdout: [ ] dart:isolate/runtime/libtimer_impl.dart 416:5 _Timer._handleMessage
stdout: [ ] dart:isolate/runtime/libisolate_patch.dart 165:12 _RawReceivePortImpl._handleMessage
stdout: [ ] ===== asynchronous gap ===========================
stdout: [ ] dart:async/zone.dart 1047:19 _CustomZone.registerCallback
stdout: [ ] dart:async/zone.dart 964:22 _CustomZone.bindCallbackGuarded
stdout: [ ] dart:async/schedule_microtask.dart 147:47 scheduleMicrotask
stdout: [ ] dart:async/runtime/libasync_patch.dart 42:7 _AsyncAwaitCompleter.completeError
stdout: [ ] test_driver/screenshot_test.dart main..
stdout: [ ] ===== asynchronous gap ===========================
stdout: [ ] dart:async/zone.dart 1047:19 _CustomZone.registerCallback
2018-07-20T16:13:00.127736: stdout: [ ] dart:async/zone.dart 964:22 _CustomZone.bindCallbackGuarded
stdout: [ ] dart:async/timer.dart 52:45 new Timer
stdout: [ ] dart:async/timer.dart 87:9 Timer.run
stdout: [ ] dart:async/future.dart 172:11 new Future
stdout: [ ] package:test/src/backend/invoker.dart 402:15 Invoker._onRun...
2018-07-20T16:13:00.141180: stdout: [ +13 ms] 00:00 �[32m+0�[0m�[31m -2�[0m: �[31mSome tests failed.�[0m