diff --git a/pkgs/checks/lib/src/extensions/iterable.dart b/pkgs/checks/lib/src/extensions/iterable.dart
index 634ca5f..b37364e 100644
--- a/pkgs/checks/lib/src/extensions/iterable.dart
+++ b/pkgs/checks/lib/src/extensions/iterable.dart
@@ -21,7 +21,7 @@
 
   void isNotEmpty() {
     context.expect(() => const ['is not empty'], (actual) {
-      if (actual.isEmpty) return null;
+      if (actual.isNotEmpty) return null;
       return Rejection(actual: literal(actual), which: ['is not empty']);
     });
   }
diff --git a/pkgs/checks/test/extensions/iterable_test.dart b/pkgs/checks/test/extensions/iterable_test.dart
new file mode 100644
index 0000000..0dbed3e
--- /dev/null
+++ b/pkgs/checks/test/extensions/iterable_test.dart
@@ -0,0 +1,56 @@
+// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
+// 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:checks/checks.dart';
+import 'package:checks/context.dart';
+import 'package:test/scaffolding.dart';
+
+import '../test_shared.dart';
+
+Iterable<int> get _testIterable => Iterable.generate(2, (i) => i);
+
+void main() {
+  test('length', () {
+    checkThat(_testIterable).length.equals(2);
+  });
+  test('first', () {
+    checkThat(_testIterable).first.equals(0);
+  });
+  test('last', () {
+    checkThat(_testIterable).last.equals(1);
+  });
+  test('single', () {
+    checkThat([42]).single.equals(42);
+  });
+
+  test('isEmpty', () {
+    checkThat([]).isEmpty();
+    checkThat(
+      softCheck<Iterable<int>>(_testIterable, (p0) => p0.isEmpty()),
+    ).isARejection(actual: '(0, 1)', which: ['is not empty']);
+  });
+
+  test('isNotEmpty', () {
+    checkThat(_testIterable).isNotEmpty();
+    checkThat(
+      softCheck<Iterable<int>>(Iterable<int>.empty(), (p0) => p0.isNotEmpty()),
+    ).isARejection(actual: '()', which: ['is not empty']);
+  });
+
+  test('contains', () {
+    checkThat(_testIterable).contains(0);
+    checkThat(
+      softCheck<Iterable<int>>(_testIterable, (p0) => p0.contains(2)),
+    ).isARejection(actual: '(0, 1)', which: ['does not contain <2>']);
+  });
+  test('contains', () {
+    checkThat(_testIterable).any((p0) => p0.equals(1));
+    checkThat(
+      softCheck<Iterable<int>>(
+        _testIterable,
+        (p0) => p0.any((p1) => p1.equals(2)),
+      ),
+    ).isARejection(actual: '(0, 1)', which: ['Contains no matching element']);
+  });
+}