From f68d1a66ccd75b0920cd9dab543207bce9989be2 Mon Sep 17 00:00:00 2001
From: Yegor <yjbanov@google.com>
Date: Tue, 1 Jun 2021 10:46:06 -0700
Subject: [PATCH] suppress output from intentionally failing tests
 (flutter/engine#26253)

* suppress output from intentionally failing tests
---
 .../flutter/lib/web_ui/dev/test_runner.dart   | 46 +++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/engine/src/flutter/lib/web_ui/dev/test_runner.dart b/engine/src/flutter/lib/web_ui/dev/test_runner.dart
index e56f400811c..5712d2a653a 100644
--- a/engine/src/flutter/lib/web_ui/dev/test_runner.dart
+++ b/engine/src/flutter/lib/web_ui/dev/test_runner.dart
@@ -10,8 +10,21 @@ import 'package:args/command_runner.dart';
 import 'package:meta/meta.dart';
 import 'package:path/path.dart' as path;
 import 'package:pool/pool.dart';
+
+// TODO(yjbanov): remove hacks when this is fixed:
+//                https://github.com/dart-lang/test/issues/1521
+import 'package:test_api/src/backend/live_test.dart'
+    as hack;
+import 'package:test_api/src/backend/group.dart'
+    as hack;
+import 'package:test_core/src/runner/configuration/reporters.dart'
+    as hack;
+import 'package:test_core/src/runner/engine.dart'
+    as hack;
 import 'package:test_core/src/runner/hack_register_platform.dart'
     as hack;
+import 'package:test_core/src/runner/reporter.dart'
+    as hack;
 import 'package:test_api/src/backend/runtime.dart';
 import 'package:test_core/src/executable.dart'
     as test;
@@ -770,6 +783,9 @@ class TestCommand extends Command<bool> with ArgUtils {
       ...<String>['-r', 'compact'],
       '--concurrency=$concurrency',
       if (isDebug) '--pause-after-load',
+      // Don't pollute logs with output from tests that are expected to fail.
+      if (expectFailure)
+        '--reporter=name-only',
       '--platform=${SupportedBrowsers.instance.supportedBrowserToPlatform[browser]}',
       '--precompiled=${environment.webUiRootDir.path}/build',
       SupportedBrowsers.instance.browserToConfiguration[browser],
@@ -777,6 +793,15 @@ class TestCommand extends Command<bool> with ArgUtils {
       ...testFiles.map((f) => f.relativeToWebUi).toList(),
     ];
 
+    if (expectFailure) {
+      hack.registerReporter(
+        'name-only',
+        hack.ReporterDetails(
+        'Prints the name of the test, but suppresses all other test output.',
+        (_, hack.Engine engine, __) => NameOnlyReporter(engine)),
+      );
+    }
+
     hack.registerPlatformPlugin(<Runtime>[
       SupportedBrowsers.instance.supportedBrowsersToRuntimes[browser]
     ], () {
@@ -801,6 +826,7 @@ class TestCommand extends Command<bool> with ArgUtils {
     if (expectFailure) {
       if (io.exitCode != 0) {
         // It failed, as expected.
+        print('Test successfully failed, as expected.');
         io.exitCode = 0;
       } else {
         io.stderr.writeln(
@@ -850,3 +876,23 @@ class TestBuildInput {
 }
 
 class TestFailureException implements Exception {}
+
+/// Prints the name of the test, but suppresses all other test output.
+///
+/// This is useful to prevent pollution of logs by tests that are expected to
+/// fail.
+class NameOnlyReporter implements hack.Reporter {
+  NameOnlyReporter(hack.Engine testEngine) {
+    testEngine.onTestStarted.listen(_printTestName);
+  }
+
+  void _printTestName(hack.LiveTest test) {
+    print('Running ${test.groups.map((hack.Group group) => group.name).join(' ')} ${test.individualName}');
+  }
+
+  @override
+  void pause() {}
+
+  @override
+  void resume() {}
+}