diff --git a/pkgs/checks/lib/src/checks.dart b/pkgs/checks/lib/src/checks.dart
index 5ac2da29c..7103ccaf5 100644
--- a/pkgs/checks/lib/src/checks.dart
+++ b/pkgs/checks/lib/src/checks.dart
@@ -225,7 +225,7 @@ extension ContextExtension<T> on Subject<T> {
 /// specific signature varies by operation.
 ///
 ///
-/// In expectation extension methods calling [expect], [expectAync], or
+/// In expectation extension methods calling [expect], [expectAsync], or
 /// [expectUnawaited], the `predicate` callback can report a [Rejection] if the
 /// value fails to satisfy the expectation.
 /// The description will be passed in a "clause" callback.
diff --git a/pkgs/checks/lib/src/extensions/iterable.dart b/pkgs/checks/lib/src/extensions/iterable.dart
index 352496079..2ab1bfa03 100644
--- a/pkgs/checks/lib/src/extensions/iterable.dart
+++ b/pkgs/checks/lib/src/extensions/iterable.dart
@@ -70,7 +70,7 @@ extension IterableChecks<T> on Subject<Iterable<T>> {
   }
 
   /// Expects that the iterable contains a value matching each expected value
-  /// from [elelements] in the given order, with any extra elements between
+  /// from [elements] in the given order, with any extra elements between
   /// them.
   ///
   /// For example, the following will succeed:
diff --git a/pkgs/checks/test/extensions/async_test.dart b/pkgs/checks/test/extensions/async_test.dart
index 43ba5d73c..5bfe55062 100644
--- a/pkgs/checks/test/extensions/async_test.dart
+++ b/pkgs/checks/test/extensions/async_test.dart
@@ -240,7 +240,7 @@ fake trace''');
             queue,
             (Subject<StreamQueue<int>> it) =>
                 it.emitsThrough((it) => it.equals(42)));
-        check(queue).emits((it) => it.equals(0));
+        await check(queue).emits((it) => it.equals(0));
       });
       test('consumes events', () async {
         final queue = _countingStream(3);
diff --git a/pkgs/checks/test/soft_check_test.dart b/pkgs/checks/test/soft_check_test.dart
index 87c9b27b8..d919b0db3 100644
--- a/pkgs/checks/test/soft_check_test.dart
+++ b/pkgs/checks/test/soft_check_test.dart
@@ -19,7 +19,7 @@ void main() {
   });
   group('softCheckAsync', () {
     test('returns the first failure', () async {
-      check(Future.value(0)).isRejectedByAsync(
+      await check(Future.value(0)).isRejectedByAsync(
           (it) => it
             ..completes((it) => it.isGreaterThan(1))
             ..completes((it) => it.isGreaterThan(2)),
diff --git a/pkgs/test_core/lib/src/bootstrap/vm.dart b/pkgs/test_core/lib/src/bootstrap/vm.dart
index a2e9f4be9..05604f120 100644
--- a/pkgs/test_core/lib/src/bootstrap/vm.dart
+++ b/pkgs/test_core/lib/src/bootstrap/vm.dart
@@ -2,6 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'dart:async';
 import 'dart:developer';
 import 'dart:io';
 import 'dart:isolate';
@@ -41,9 +42,9 @@ void internalBootstrapNativeTest(
     ..pipe(serializeSuite(getMain));
   platformChannel.sink.add(testControlChannel.id);
 
-  platformChannel.stream.forEach((message) {
+  unawaited(platformChannel.stream.forEach((message) {
     assert(message == 'debug');
     debugger(message: 'Paused by test runner');
     platformChannel.sink.add('done');
-  });
+  }));
 }
diff --git a/pkgs/test_core/lib/src/runner/console.dart b/pkgs/test_core/lib/src/runner/console.dart
index b716aad2c..dc1bba5c1 100644
--- a/pkgs/test_core/lib/src/runner/console.dart
+++ b/pkgs/test_core/lib/src/runner/console.dart
@@ -111,7 +111,7 @@ class _Command {
   final String description;
 
   /// The callback to run when the command is invoked.
-  final Function body;
+  final dynamic Function() body;
 
   _Command(this.name, this.description, this.body);
 }
diff --git a/pkgs/test_core/lib/src/runner/engine.dart b/pkgs/test_core/lib/src/runner/engine.dart
index 0aa29e604..6a6362761 100644
--- a/pkgs/test_core/lib/src/runner/engine.dart
+++ b/pkgs/test_core/lib/src/runner/engine.dart
@@ -387,7 +387,9 @@ class Engine {
     await Future(() {});
 
     if (!_restarted.contains(liveTest)) {
-      if (_stopOnFirstFailure && liveTest.state.result.isFailing) close();
+      if (_stopOnFirstFailure && liveTest.state.result.isFailing) {
+        unawaited(close());
+      }
       return;
     }
     await _runLiveTest(suiteController, liveTest.copy(),
diff --git a/pkgs/test_core/lib/src/runner/load_suite.dart b/pkgs/test_core/lib/src/runner/load_suite.dart
index d4263ea01..550881e0c 100644
--- a/pkgs/test_core/lib/src/runner/load_suite.dart
+++ b/pkgs/test_core/lib/src/runner/load_suite.dart
@@ -14,7 +14,6 @@ import 'package:test_api/src/backend/suite.dart'; // ignore: implementation_impo
 import 'package:test_api/src/backend/suite_platform.dart'; // ignore: implementation_imports
 import 'package:test_api/src/backend/test.dart'; // ignore: implementation_imports
 
-import '../util/async.dart';
 import '../util/io_stub.dart' if (dart.library.io) '../util/io.dart';
 import '../util/pair.dart';
 import 'load_exception.dart';
diff --git a/pkgs/test_core/lib/src/runner/runner_test.dart b/pkgs/test_core/lib/src/runner/runner_test.dart
index f140c0155..2823983e2 100644
--- a/pkgs/test_core/lib/src/runner/runner_test.dart
+++ b/pkgs/test_core/lib/src/runner/runner_test.dart
@@ -43,23 +43,24 @@ class RunnerTest extends Test {
       _channel.sink.add({'command': 'run', 'channel': testChannel.id});
 
       testChannel.stream.listen((message) {
-        switch (message['type'] as String) {
+        final msg = message as Map;
+        switch (msg['type'] as String) {
           case 'error':
             var asyncError = RemoteException.deserialize(
-                message['error'] as Map<String, dynamic>);
+                msg['error'] as Map<String, dynamic>);
             var stackTrace = asyncError.stackTrace;
             controller.addError(asyncError.error, stackTrace);
             break;
 
           case 'state-change':
-            controller.setState(State(Status.parse(message['status'] as String),
-                Result.parse(message['result'] as String)));
+            controller.setState(State(Status.parse(msg['status'] as String),
+                Result.parse(msg['result'] as String)));
             break;
 
           case 'message':
             controller.message(Message(
-                MessageType.parse(message['message-type'] as String),
-                message['text'] as String));
+                MessageType.parse(msg['message-type'] as String),
+                msg['text'] as String));
             break;
 
           case 'complete':
@@ -70,9 +71,8 @@ class RunnerTest extends Test {
             // When we kill the isolate that the test lives in, that will close
             // this virtual channel and cause the spawned isolate to close as
             // well.
-            spawnHybridUri(message['url'] as String, message['message'], suite)
-                .pipe(testChannel
-                    .virtualChannel((message['channel'] as num).toInt()));
+            spawnHybridUri(msg['url'] as String, msg['message'], suite).pipe(
+                testChannel.virtualChannel((msg['channel'] as num).toInt()));
             break;
         }
       }, onDone: () {
diff --git a/pkgs/test_core/lib/src/runner/vm/platform.dart b/pkgs/test_core/lib/src/runner/vm/platform.dart
index aa4eeb81a..85f691d7a 100644
--- a/pkgs/test_core/lib/src/runner/vm/platform.dart
+++ b/pkgs/test_core/lib/src/runner/vm/platform.dart
@@ -59,7 +59,7 @@ class VMPlatform extends PlatformPlugin {
         process =
             await _spawnExecutable(path, suiteConfig.metadata, serverSocket);
       } catch (error) {
-        serverSocket.close();
+        unawaited(serverSocket.close());
         rethrow;
       }
       process.stdout.listen(stdout.add);
@@ -100,8 +100,8 @@ class VMPlatform extends PlatformPlugin {
       for (var fn in cleanupCallbacks) {
         fn();
       }
-      eventSub?.cancel();
-      client?.dispose();
+      unawaited(eventSub?.cancel());
+      unawaited(client?.dispose());
       sink.close();
     }));
 
diff --git a/pkgs/test_core/lib/src/scaffolding.dart b/pkgs/test_core/lib/src/scaffolding.dart
index b72d9eab3..93343fef1 100644
--- a/pkgs/test_core/lib/src/scaffolding.dart
+++ b/pkgs/test_core/lib/src/scaffolding.dart
@@ -16,7 +16,6 @@ import 'runner/plugin/environment.dart';
 import 'runner/reporter/expanded.dart';
 import 'runner/runner_suite.dart';
 import 'runner/suite.dart';
-import 'util/async.dart';
 import 'util/os.dart';
 import 'util/print_sink.dart';
 
diff --git a/pkgs/test_core/lib/src/util/async.dart b/pkgs/test_core/lib/src/util/async.dart
index 422de0e23..036d2b1cf 100644
--- a/pkgs/test_core/lib/src/util/async.dart
+++ b/pkgs/test_core/lib/src/util/async.dart
@@ -30,5 +30,3 @@ Stream<T> inCompletionOrder<T>(Iterable<CancelableOperation<T>> operations) {
 
   return controller.stream;
 }
-
-void unawaited(Future<void> f) {}
diff --git a/pkgs/test_core/lib/src/util/io.dart b/pkgs/test_core/lib/src/util/io.dart
index d6be8431d..a082dd310 100644
--- a/pkgs/test_core/lib/src/util/io.dart
+++ b/pkgs/test_core/lib/src/util/io.dart
@@ -44,10 +44,11 @@ final String sdkDir = p.dirname(p.dirname(Platform.resolvedExecutable));
 /// The current operating system.
 final currentOS = OperatingSystem.findByIoName(Platform.operatingSystem);
 
-/// Returns a [SuitePlatform] with the given [runtime], and with [os] and
-/// [inGoogle] determined automatically.
+/// Returns a [SuitePlatform] with the given [runtime], and with
+/// [SuitePlatform.os] and [inGoogle] determined automatically.
 ///
-/// If [runtime] is a browser, this will set [os] to [OperatingSystem.none].
+/// If [runtime] is a browser, this will set [SuitePlatform.os] to
+/// [OperatingSystem.none].
 // TODO: https://github.com/dart-lang/test/issues/2119 - require compiler
 SuitePlatform currentPlatform(Runtime runtime, [Compiler? compiler]) =>
     SuitePlatform(runtime,
@@ -223,7 +224,8 @@ Future<Uri> getRemoteDebuggerUrl(Uri base) async {
     var response = await request.close();
     var jsonObject =
         await json.fuse(utf8).decoder.bind(response).single as List;
-    return base.resolve(jsonObject.first['devtoolsFrontendUrl'] as String);
+    return base
+        .resolve((jsonObject.first as Map)['devtoolsFrontendUrl'] as String);
   } catch (_) {
     // If we fail to talk to the remote debugger protocol, give up and return
     // the raw URL rather than crashing.