diff --git a/test/dart_kollection_test.dart b/test/dart_kollection_test.dart
index 63f387a7..29f09263 100644
--- a/test/dart_kollection_test.dart
+++ b/test/dart_kollection_test.dart
@@ -18,6 +18,8 @@ import 'collections_test.dart' as collections_test;
 import 'comparisons_test.dart' as comparisons_test;
 import 'exceptions_test.dart' as exceptions_test;
 import 'tuples_test.dart' as tuples_test;
+import 'util/annotation_test.dart' as annotation_test;
+import 'util/hash_test.dart' as hash_test;
 
 void main() {
   collection_mutable_test.main();
@@ -38,4 +40,6 @@ void main() {
   comparisons_test.main();
   exceptions_test.main();
   tuples_test.main();
+  annotation_test.main();
+  hash_test.main();
 }
diff --git a/test/util/annotation_test.dart b/test/util/annotation_test.dart
new file mode 100644
index 00000000..81ea2177
--- /dev/null
+++ b/test/util/annotation_test.dart
@@ -0,0 +1,19 @@
+import 'package:dart_kollection/src/util/annotations.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test("nullable is _Nullable", () {
+    expect(nullable.runtimeType.toString(), equals("_Nullable"));
+  });
+  test("nonNull is _NonNull", () {
+    expect(nonNull.runtimeType.toString(), equals("_NonNull"));
+  });
+  test("tooGeneric is TooGeneric", () {
+    expect(tooGeneric, equals(const TypeMatcher<TooGeneric>()));
+  });
+  test("TooGeneric has extensionForType property", () {
+    const annotation = TooGeneric(extensionForType: "SomeType");
+    expect(annotation, equals(const TypeMatcher<TooGeneric>()));
+    expect(annotation.extensionForType, equals("SomeType"));
+  });
+}
diff --git a/test/util/hash_test.dart b/test/util/hash_test.dart
new file mode 100644
index 00000000..8a474da4
--- /dev/null
+++ b/test/util/hash_test.dart
@@ -0,0 +1,23 @@
+import 'package:dart_kollection/src/util/hash.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test("hash2", () {
+    expect(hash2("foo", "bar"), equals(422905972));
+    expect(hashObjects(["foo", "bar"]), equals(422905972));
+    expect(hash2("bar", "foo"), equals(293502445));
+    expect(hashObjects(["bar", "foo"]), equals(293502445));
+  });
+  test("hash3", () {
+    expect(hash3("foo", "bar", "baz"), equals(247754790));
+    expect(hashObjects(["foo", "bar", "baz"]), equals(247754790));
+    expect(hash3("baz", "bar", "foo"), equals(413548564));
+    expect(hashObjects(["baz", "bar", "foo"]), equals(413548564));
+  });
+  test("hash4", () {
+    expect(hash4("foo", "bar", "baz", "qux"), equals(263375993));
+    expect(hashObjects(["foo", "bar", "baz", "qux"]), equals(263375993));
+    expect(hash4("baz", "bar", "foo", "qux"), equals(264235936));
+    expect(hashObjects(["baz", "bar", "foo", "qux"]), equals(264235936));
+  });
+}