diff --git a/hash/sha256.test.js b/hash/sha256.test.js
index ba1444d..3ef324a 100644
--- a/hash/sha256.test.js
+++ b/hash/sha256.test.js
@@ -9,6 +9,14 @@ import * as env from '../environment.js'
 import * as array from '../array.js'
 import * as f from '../function.js'
 
+/**
+ * @param {t.TestCase} _tc
+ */
+export const testSelfReferencingHash = _tc => {
+  const hash = sha256.digest(string.encodeUtf8('The SHA256 for this sentence begins with: one, eight, two, a, seven, c and nine.'))
+  t.assert(buffer.toHexString(hash).startsWith('182a7c9'))
+}
+
 /**
  * @param {t.TestCase} _tc
  */