diff --git a/src/utils.rs b/src/utils.rs
index a619b5e..8b425b2 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -62,4 +62,24 @@ pub mod shasum {
 
         out
     }
+
+    #[cfg(test)]
+    mod test {
+        use crate::utils::shasum::sha256sum_to_hex_string;
+
+        #[test]
+        fn sha256sum_string() {
+            let null_sha = sha256sum_to_hex_string(&[0; 32]);
+            let full_sha = sha256sum_to_hex_string(&[0xff; 32]);
+
+            assert_eq!(
+                null_sha,
+                "0000000000000000000000000000000000000000000000000000000000000000"
+            );
+            assert_eq!(
+                full_sha,
+                "ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"
+            );
+        }
+    }
 }