diff --git a/tests/test-base-64.cpp b/tests/test-base-64.cpp
index 0ab46c06..63817bf4 100644
--- a/tests/test-base-64.cpp
+++ b/tests/test-base-64.cpp
@@ -11,8 +11,7 @@ int main() {
   char out[16];
 
   /* bytes -> b64 */
-  assert(ByteStreamToBase64(NULL, 0, NULL, 0) == 0);
-  assert(ByteStreamToBase64(NULL, 0, out, sizeof(out)) == 0);
+  assert(ByteStreamToBase64(NULL, 0) == "");
 
   assert(Base64EncodingBufferSize(2)  == 4);
   assert(Base64EncodingBufferSize(4)  == 8);
@@ -23,19 +22,20 @@ int main() {
   assert(Base64EncodingBufferSize(12) == 16);
   assert(Base64EncodingBufferSize(13) == 20);
 
-  assert(ByteStreamToBase64((uint8_t *) in, in_len, out, sizeof(out)) == 8);
-  assert(memcmp(out, "dGVzdA==", 8) == 0);
+  const std::string out_str(ByteStreamToBase64((uint8_t *) in, in_len));
+  assert(out_str.size() == 8);
+  assert(out_str == "dGVzdA==");
 
   /* b64 -> bytes */
-  assert(Base64ToByteStream(NULL, 0, NULL, 0) == 0);
-  assert(Base64ToByteStream(NULL, 0, (uint8_t *) out, sizeof(out)) == 0);
+  assert(Base64ToByteStream("", NULL, 0) == 0);
+  assert(Base64ToByteStream("", (uint8_t *) out, sizeof(out)) == 0);
 
   in = "dGVzdA=="; /* valid b64 */
-  assert(Base64ToByteStream(in, strlen(in), (uint8_t *) out, sizeof(out)) == 4);
+  assert(Base64ToByteStream(in, (uint8_t *) out, sizeof(out)) == 4);
   assert(memcmp(out, "test", 4) == 0);
 
   in = "dGVzdA=";  /* invalid b64 : not padded */
-  assert(Base64ToByteStream(in, strlen(in), (uint8_t *) out, sizeof(out)) == 0);
+  assert(Base64ToByteStream(in, (uint8_t *) out, sizeof(out)) == 0);
 
   in = "dG/z.A=="; /* invalid b64 : char not from alphabet */
 //  assert(Base64ToByteStream(in, strlen(in), (uint8_t *) out, sizeof(out)) == 0);