encoding: convert to span

Change-Id: I8bd73284fbd5acc0ff8ad2626af9b4324e9df7a1
diff --git a/tests/unit/util/sha256.t.cpp b/tests/unit/util/sha256.t.cpp
index 501a015..3340204 100644
--- a/tests/unit/util/sha256.t.cpp
+++ b/tests/unit/util/sha256.t.cpp
@@ -134,7 +134,7 @@
   auto expected = fromHex("b372edfd4d6a4db2cfeaeead6c34fdee9b9e759f7b8d799cf8067e39e7f2886c");
 
   Sha256 statefulSha256;
-  statefulSha256 << Block{input, sizeof(input)};
+  statefulSha256 << Block{input};
   ConstBufferPtr digest = statefulSha256.computeDigest();
 
   BOOST_CHECK_EQUAL(statefulSha256.empty(), false);