Add a timeout to bot tests. (#16666)

This will catch the case where tests hang -- and it will
force them to fail so that we see the output from the test.

dev/bots/test.dart

@@ -32,6 +32,9 @@ const Map<String, ShardRunner> _kShards = const <String, ShardRunner>{
   'coverage': _runCoverage,
 };
 
+const Duration _kLongTimeout = const Duration(minutes: 45);
+const Duration _kShortTimeout = const Duration(minutes: 5);
+
 /// When you call this, you can pass additional arguments to pass custom
 /// arguments to flutter test. For example, you might want to call this
 /// script with the parameter --local-engine=host_debug_unopt to
@@ -143,35 +146,41 @@ Future<Null> _runTests({List<String> options: const <String>[]}) async {
     options: options,
     expectFailure: true,
     printOutput: false,
+    timeout: _kShortTimeout,
   );
   await _runFlutterTest(automatedTests,
     script: path.join('test_smoke_test', 'pass_test.dart'),
     options: options,
     printOutput: false,
+    timeout: _kShortTimeout,
   );
   await _runFlutterTest(automatedTests,
     script: path.join('test_smoke_test', 'crash1_test.dart'),
     options: options,
     expectFailure: true,
     printOutput: false,
+    timeout: _kShortTimeout,
   );
   await _runFlutterTest(automatedTests,
     script: path.join('test_smoke_test', 'crash2_test.dart'),
     options: options,
     expectFailure: true,
     printOutput: false,
+    timeout: _kShortTimeout,
   );
   await _runFlutterTest(automatedTests,
     script: path.join('test_smoke_test', 'syntax_error_test.broken_dart'),
     options: options,
     expectFailure: true,
     printOutput: false,
+    timeout: _kShortTimeout,
   );
   await _runFlutterTest(automatedTests,
     script: path.join('test_smoke_test', 'missing_import_test.broken_dart'),
     options: options,
     expectFailure: true,
     printOutput: false,
+    timeout: _kShortTimeout,
   );
   await _runCommand(flutter,
     <String>['drive', '--use-existing-app']
@@ -180,6 +189,7 @@ Future<Null> _runTests({List<String> options: const <String>[]}) async {
     workingDirectory: path.join(flutterRoot, 'packages', 'flutter_driver'),
     expectFailure: true,
     printOutput: false,
+    timeout: _kShortTimeout,
   );
 
   // Verify that we correctly generated the version file.
@@ -313,6 +323,7 @@ Future<Null> _runCommand(String executable, List<String> arguments, {
   bool expectFailure: false,
   bool printOutput: true,
   bool skip: false,
+  Duration timeout: _kLongTimeout,
 }) async {
   final String commandDescription = '${path.relative(executable, from: workingDirectory)} ${arguments.join(' ')}';
   final String relativeWorkingDir = path.relative(workingDirectory);
@@ -336,11 +347,14 @@ Future<Null> _runCommand(String executable, List<String> arguments, {
     savedStderr = process.stderr.toList();
   }
 
-  final int exitCode = await process.exitCode;
+  final int exitCode = await process.exitCode.timeout(timeout, onTimeout: () {
+    stderr.writeln('Process timed out after $timeout');
+    return expectFailure ? 0 : 1;
+  });
   if ((exitCode == 0) == expectFailure) {
     if (!printOutput) {
-      print(utf8.decode((await savedStdout).expand((List<int> ints) => ints).toList()));
-      print(utf8.decode((await savedStderr).expand((List<int> ints) => ints).toList()));
+      stdout.writeln(utf8.decode((await savedStdout).expand((List<int> ints) => ints).toList()));
+      stderr.writeln(utf8.decode((await savedStderr).expand((List<int> ints) => ints).toList()));
     }
     print(
       '$red━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━$reset\n'
@@ -357,6 +371,7 @@ Future<Null> _runFlutterTest(String workingDirectory, {
   bool printOutput: true,
   List<String> options: const <String>[],
   bool skip: false,
+  Duration timeout: _kLongTimeout,
 }) {
   final List<String> args = <String>['test']..addAll(options);
   if (flutterTestArgs != null && flutterTestArgs.isNotEmpty)
@@ -368,6 +383,7 @@ Future<Null> _runFlutterTest(String workingDirectory, {
     expectFailure: expectFailure,
     printOutput: printOutput,
     skip: skip,
+    timeout: timeout,
   );
 }