Throw when an async matcher is used with isNot

pkgs/matcher/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.12.21-wip
+
+* Throw an `ArgumentError` when `isNot` or `anyOf` is used with an `AsyncMatcher`.
+
 ## 0.12.20
 
 * Allow exceptions from `operator ==` to bubble up and fail the test instead of

pkgs/matcher/lib/src/operator_matchers.dart

@@ -2,11 +2,18 @@
 // 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 'expect/async_matcher.dart';
 import 'interfaces.dart';
 import 'util.dart';
 
 /// Returns a matcher that inverts [valueOrMatcher] to its logical negation.
-Matcher isNot(Object? valueOrMatcher) => _IsNot(wrapMatcher(valueOrMatcher));
+Matcher isNot(Object? valueOrMatcher) {
+  final matcher = wrapMatcher(valueOrMatcher);
+  if (matcher is AsyncMatcher) {
+    throw ArgumentError('isNot cannot be used with AsyncMatchers');
+  }
+  return _IsNot(matcher);
+}
 
 class _IsNot extends Matcher {
   final Matcher _matcher;
@@ -108,6 +115,9 @@ class _AnyOf extends Matcher {
   @override
   bool matches(dynamic item, Map matchState) {
     for (var matcher in _matchers) {
+      if (matcher is AsyncMatcher) {
+        throw ArgumentError('anyOf cannot be used with AsyncMatchers');
+      }
       if (matcher.matches(item, matchState)) {
         return true;
       }

pkgs/matcher/pubspec.yaml

@@ -1,5 +1,5 @@
 name: matcher
-version: 0.12.20
+version: 0.12.21-wip
 description: >-
   Support for specifying test expectations via an extensible Matcher class.
   Also includes a number of built-in Matcher implementations for common cases.

pkgs/matcher/test/expect_test.dart

@@ -34,9 +34,5 @@ void main() {
         throwsA(isTestFailure(anything)),
       );
     });
-
-    test('can be used with synchronous operators', () {
-      expect(() {}, isNot(throwsA(anything)));
-    });
   });
 }

pkgs/matcher/test/operator_matchers_test.dart

@@ -2,8 +2,9 @@
 // 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 'package:matcher/expect.dart' show expect, throwsA, throwsArgumentError;
 import 'package:matcher/matcher.dart';
-import 'package:test/test.dart' show expect, test, throwsArgumentError;
+import 'package:test/test.dart' show test;
 
 import 'test_utils.dart';
 
@@ -86,4 +87,13 @@ void main() {
       throwsArgumentError,
     );
   });
+
+  test('isNot throws ArgumentError for AsyncMatcher', () {
+    expect(() => isNot(throwsA(anything)), throwsArgumentError);
+  });
+
+  test('anyOf throws ArgumentError for AsyncMatcher', () {
+    final matcher = anyOf(throwsA(anything));
+    expect(() => matcher.matches(null, {}), throwsArgumentError);
+  });
 }