make integration_test_driver_extended.dart support writeResponseData--(done) (#128382)

*Replace this paragraph with a description of what this PR is changing or adding, and why. Consider including before/after screenshots.*

*List which issues are fixed by this PR. You must list at least one issue.*
- flutter/flutter#128381

*If you had to change anything in the [flutter/tests] repo, include a link to the migration guide as per the [breaking change policy].*

Author: linchen2chris

dev/bots/test.dart

@@ -1181,13 +1181,29 @@ Future<void> _runWebLongRunningTests() async {
         driver: path.join('test_driver', 'integration_test.dart'),
         buildMode: buildMode,
         renderer: 'canvaskit',
+        expectWriteResponseFile: true,
+        expectResponseFileContent: 'null',
       ),
       () => _runFlutterDriverWebTest(
         testAppDirectory: path.join('packages', 'integration_test', 'example'),
         target: path.join('integration_test', 'extended_test.dart'),
         driver: path.join('test_driver', 'extended_integration_test.dart'),
         buildMode: buildMode,
         renderer: 'canvaskit',
+        expectWriteResponseFile: true,
+        expectResponseFileContent: '''
+{
+  "screenshots": [
+    {
+      "screenshotName": "platform_name",
+      "bytes": []
+    },
+    {
+      "screenshotName": "platform_name_2",
+      "bytes": []
+    }
+  ]
+}''',
       ),
     ],
 
@@ -1321,13 +1337,20 @@ Future<void> _runFlutterDriverWebTest({
   String? driver,
   bool expectFailure = false,
   bool silenceBrowserOutput = false,
+  bool expectWriteResponseFile = false,
+  String expectResponseFileContent = '',
 }) async {
   printProgress('${green}Running integration tests $target in $buildMode mode.$reset');
   await runCommand(
     flutter,
     <String>[ 'clean' ],
     workingDirectory: testAppDirectory,
   );
+  final String responseFile =
+      path.join(testAppDirectory, 'build', 'integration_response_data.json');
+  if (File(responseFile).existsSync()) {
+    File(responseFile).deleteSync();
+  }
   await runCommand(
     flutter,
     <String>[
@@ -1356,6 +1379,20 @@ Future<void> _runFlutterDriverWebTest({
       return false;
     },
   );
+  if (expectWriteResponseFile) {
+    if (!File(responseFile).existsSync()) {
+      foundError(<String>[
+        '$bold${red}Command did not write the response file but expected response file written.$reset',
+      ]);
+    } else {
+      final String response = File(responseFile).readAsStringSync();
+      if (response != expectResponseFileContent) {
+        foundError(<String>[
+          '$bold${red}Command write the response file with $response but expected response file with $expectResponseFileContent.$reset',
+        ]);
+      }
+    }
+  }
 }
 
 // Compiles a sample web app and checks that its JS doesn't contain certain

packages/integration_test/example/test_driver/extended_integration_test.dart

@@ -25,5 +25,5 @@ Future<void> main() async {
       }
       return true;
     },
-  );
+    writeResponseOnFailure: true);
 }

packages/integration_test/example/test_driver/integration_test.dart

@@ -4,4 +4,4 @@
 
 import 'package:integration_test/integration_test_driver.dart';
 
-Future<void> main() => integrationDriver();
+Future<void> main() => integrationDriver(writeResponseOnFailure: true);

packages/integration_test/lib/integration_test_driver.dart

@@ -67,9 +67,14 @@ Future<void> writeResponseData(
 ///
 /// `responseDataCallback` is the handler for processing [Response.data].
 /// The default value is `writeResponseData`.
+///
+/// `writeResponseOnFailure` determines whether the `responseDataCallback`
+/// function will be called to process the [Response.data] when a test fails.
+/// The default value is `false`.
 Future<void> integrationDriver({
   Duration timeout = const Duration(minutes: 20),
   ResponseDataCallback? responseDataCallback = writeResponseData,
+  bool writeResponseOnFailure = false,
 }) async {
   final FlutterDriver driver = await FlutterDriver.connect();
   final String jsonResult = await driver.requestData(null, timeout: timeout);
@@ -85,6 +90,9 @@ Future<void> integrationDriver({
     exit(0);
   } else {
     print('Failure Details:\n${response.formattedFailureDetails}');
+    if (responseDataCallback != null && writeResponseOnFailure) {
+      await responseDataCallback(response.data);
+    }
     exit(1);
   }
 }

packages/integration_test/lib/integration_test_driver_extended.dart

@@ -6,12 +6,45 @@
 // ignore_for_file: avoid_print
 
 import 'dart:async';
+import 'dart:convert';
 import 'dart:io';
 
 import 'package:flutter_driver/flutter_driver.dart';
+import 'package:path/path.dart' as path;
 
 import 'common.dart';
 
+/// Flutter Driver test output directory.
+///
+/// Tests should write any output files to this directory. Defaults to the path
+/// set in the FLUTTER_TEST_OUTPUTS_DIR environment variable, or `build` if
+/// unset.
+String testOutputsDirectory =
+    Platform.environment['FLUTTER_TEST_OUTPUTS_DIR'] ?? 'build';
+
+/// The callback type to handle [Response.data] after the test
+/// succeeds.
+typedef ResponseDataCallback = FutureOr<void> Function(Map<String, dynamic>?);
+
+/// Writes a json-serializable data to
+/// [testOutputsDirectory]/`testOutputFilename.json`.
+///
+/// This is the default `responseDataCallback` in [integrationDriver].
+Future<void> writeResponseData(
+  Map<String, dynamic>? data, {
+  String testOutputFilename = 'integration_response_data',
+  String? destinationDirectory,
+}) async {
+  destinationDirectory ??= testOutputsDirectory;
+  await fs.directory(destinationDirectory).create(recursive: true);
+  final File file = fs.file(path.join(
+    destinationDirectory,
+    '$testOutputFilename.json',
+  ));
+  final String resultString = _encodeJson(data, true);
+  await file.writeAsString(resultString);
+}
+
 /// Adaptor to run an integration test using `flutter drive`.
 ///
 /// To an integration test `<test_name>.dart` using `flutter drive`, put a file named
@@ -43,8 +76,19 @@ import 'common.dart';
 /// and it returns `true` if both images are equal.
 ///
 /// As a result, returning `false` from `onScreenshot` will make the test fail.
-Future<void> integrationDriver(
-    {FlutterDriver? driver, ScreenshotCallback? onScreenshot}) async {
+///
+/// `responseDataCallback` is the handler for processing [Response.data].
+/// The default value is `writeResponseData`.
+///
+/// `writeResponseOnFailure` determines whether the `responseDataCallback`
+/// function will be called to process the [Response.data] when a test fails.
+/// The default value is `false`.
+Future<void> integrationDriver({
+  FlutterDriver? driver,
+  ScreenshotCallback? onScreenshot,
+  ResponseDataCallback? responseDataCallback = writeResponseData,
+  bool writeResponseOnFailure = false,
+}) async {
   driver ??= await FlutterDriver.connect();
   // Test states that it's waiting on web driver commands.
   // [DriverTestMessage] is converted to string since json format causes an
@@ -130,9 +174,21 @@ Future<void> integrationDriver(
 
   if (response.allTestsPassed) {
     print('All tests passed.');
+    if (responseDataCallback != null) {
+      await responseDataCallback(response.data);
+    }
     exit(0);
   } else {
     print('Failure Details:\n${response.formattedFailureDetails}');
+    if (responseDataCallback != null && writeResponseOnFailure) {
+      await responseDataCallback(response.data);
+    }
     exit(1);
   }
 }
+
+const JsonEncoder _prettyEncoder = JsonEncoder.withIndent('  ');
+
+String _encodeJson(Map<String, dynamic>? jsonObject, bool pretty) {
+  return pretty ? _prettyEncoder.convert(jsonObject) : json.encode(jsonObject);
+}