diff --git a/apkverify/src/testing.rs b/apkverify/src/testing.rs
new file mode 100644
index 0000000..777afb8
--- /dev/null
+++ b/apkverify/src/testing.rs
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//! A collection of utilities for testing
+
+/// Asserts if `haystack.contains(needed)`
+#[macro_export]
+macro_rules! assert_contains {
+    ($haystack:expr,$needle:expr $(,)?) => {
+        match (&$haystack, &$needle) {
+            (haystack_value, needle_value) => {
+                assert!(
+                    haystack_value.contains(needle_value),
+                    "{} is not found in {}",
+                    needle_value,
+                    haystack_value
+                );
+            }
+        }
+    };
+}