[flutter_tools] dont require a device for screenshot type skia/rasterizer (#80153)

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

@@ -65,9 +65,13 @@ class ScreenshotCommand extends FlutterCommand {
 
   Device device;
 
-  static void validateOptions(String screenshotType, Device device, String observatoryUri) {
+  Future<void> _validateOptions(String screenshotType, String observatoryUri) async {
     switch (screenshotType) {
       case _kDeviceType:
+        if (observatoryUri != null) {
+          throwToolExit('Observatory URI cannot be provided for screenshot type $screenshotType');
+        }
+        device = await findTargetDevice();
         if (device == null) {
           throwToolExit('Must have a connected device for screenshot type $screenshotType');
         }
@@ -87,8 +91,7 @@ class ScreenshotCommand extends FlutterCommand {
 
   @override
   Future<FlutterCommandResult> verifyThenRunCommand(String commandPath) async {
-    device = await findTargetDevice();
-    validateOptions(stringArg(_kType), device, stringArg(_kObservatoryUri));
+    await _validateOptions(stringArg(_kType), stringArg(_kObservatoryUri));
     return super.verifyThenRunCommand(commandPath);
   }
 

packages/flutter_tools/test/commands.shard/hermetic/screenshot_command_test.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// @dart = 2.8
+
+import 'package:flutter_tools/src/base/io.dart';
+import 'package:flutter_tools/src/base/logger.dart';
+import 'package:flutter_tools/src/cache.dart';
+import 'package:flutter_tools/src/commands/screenshot.dart';
+import 'package:flutter_tools/src/vmservice.dart';
+
+import '../../src/common.dart';
+import '../../src/context.dart';
+import '../../src/test_flutter_command_runner.dart';
+
+void main() {
+  setUpAll(() {
+    Cache.disableLocking();
+  });
+
+  group('Validate screenshot options', () {
+    testUsingContext('rasterizer and skia screenshots do not require a device', () async {
+      // Throw a specific exception when attempting to make a VM Service connection to
+      // verify that we've made it past the initial validation.
+      openChannelForTesting = (String url, {CompressionOptions compression, Logger logger}) async {
+        expect(url, 'ws://localhost:8181/ws');
+        throw Exception('dummy');
+      };
+
+      await expectLater(() => createTestCommandRunner(ScreenshotCommand())
+        .run(<String>['screenshot', '--type=skia', '--observatory-uri=http://localhost:8181']),
+        throwsA(isA<Exception>().having((dynamic exception) => exception.toString(), 'message', contains('dummy'))),
+      );
+
+      await expectLater(() => createTestCommandRunner(ScreenshotCommand())
+        .run(<String>['screenshot', '--type=rasterizer', '--observatory-uri=http://localhost:8181']),
+        throwsA(isA<Exception>().having((dynamic exception) => exception.toString(), 'message', contains('dummy'))),
+      );
+    });
+
+
+    testUsingContext('rasterizer and skia screenshots require observatory uri', () async {
+      await expectLater(() => createTestCommandRunner(ScreenshotCommand())
+        .run(<String>['screenshot', '--type=skia']),
+        throwsToolExit(message: 'Observatory URI must be specified for screenshot type skia')
+      );
+
+      await expectLater(() => createTestCommandRunner(ScreenshotCommand())
+        .run(<String>['screenshot', '--type=rasterizer',]),
+        throwsToolExit(message: 'Observatory URI must be specified for screenshot type rasterizer'),
+      );
+    });
+
+    testUsingContext('device screenshots require device', () async {
+      await expectLater(() => createTestCommandRunner(ScreenshotCommand())
+        .run(<String>['screenshot']),
+        throwsToolExit(message: 'Must have a connected device for screenshot type device'),
+      );
+    });
+
+    testUsingContext('device screenshots cannot provided Observatory', () async {
+      await expectLater(() => createTestCommandRunner(ScreenshotCommand())
+        .run(<String>['screenshot',  '--observatory-uri=http://localhost:8181']),
+        throwsToolExit(message: 'Observatory URI cannot be provided for screenshot type device'),
+      );
+    });
+  });
+}

packages/flutter_tools/test/general.shard/screenshot_command_test.dart

-// Copyright 2014 The Flutter Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// @dart = 2.8
-
-import 'package:flutter_tools/src/commands/screenshot.dart';
-
-import '../src/common.dart';
-import '../src/context.dart';
-
-void main() {
-  group('Validate screenshot options', () {
-    testUsingContext('rasterizer and skia screenshots do not require a device', () async {
-      ScreenshotCommand.validateOptions('rasterizer', null, 'dummy_observatory_uri');
-      ScreenshotCommand.validateOptions('skia', null, 'dummy_observatory_uri');
-    });
-
-    testUsingContext('rasterizer and skia screenshots require observatory uri', () async {
-      expect(
-          () => ScreenshotCommand.validateOptions('rasterizer', null, null),
-          throwsToolExit(
-              message:
-                  'Observatory URI must be specified for screenshot type rasterizer'));
-      expect(
-          () => ScreenshotCommand.validateOptions('skia', null, null),
-          throwsToolExit(
-              message:
-                  'Observatory URI must be specified for screenshot type skia'));
-      expect(() => ScreenshotCommand.validateOptions('skia', null, ''),
-          throwsToolExit(message: 'Observatory URI "" is invalid'));
-    });
-
-    testUsingContext('device screenshots require device', () async {
-      expect(() => ScreenshotCommand.validateOptions('device', null, null), throwsToolExit());
-    });
-  });
-}