diff --git a/stdlib/SHA/src/SHA.jl b/stdlib/SHA/src/SHA.jl
index 7edaab403156a..ac93fdf13f442 100644
--- a/stdlib/SHA/src/SHA.jl
+++ b/stdlib/SHA/src/SHA.jl
@@ -124,7 +124,7 @@ for (f, ctx) in [(:sha1, :SHA1_CTX),
         end
         function $g(key::Vector{UInt8}, io::IO, chunk_size=4*1024)
             ctx = HMAC_CTX($ctx(), key)
-            buff = Vector{UInt8}(chunk_size)
+            buff = Vector{UInt8}(undef, chunk_size)
             while !eof(io)
                 num_read = readbytes!(io, buff)
                 update!(ctx, buff, num_read)
diff --git a/stdlib/SHA/test/runtests.jl b/stdlib/SHA/test/runtests.jl
index 2430f8d0b1089..49ab05e47b739 100644
--- a/stdlib/SHA/test/runtests.jl
+++ b/stdlib/SHA/test/runtests.jl
@@ -230,15 +230,17 @@ for (key, msg, fun, hash) in (
     (b"key", b"The quick brown fox jumps over the lazy dog", hmac_sha256, "f7bc83f430538424b13298e6aa6fb143ef4d59a14946175997479dbc2d1a3cd8"),
 )
     global nerrors
-    digest = bytes2hex(fun(Vector(key), Vector(msg)))
-    if digest != hash
+    digest1 = bytes2hex(fun(Vector(key), Vector(msg)))
+    digest2 = bytes2hex(fun(Vector(key), IOBuffer(Vector(msg))))
+    if digest1 != hash || digest2 != hash
         print("\n")
         @warn(
         """
         For $fun($(String(key)), $(String(msg))) expected:
             $hash
         Calculated:
-            $digest
+            $digest1
+            $digest2
         """)
         nerrors += 1
     else