diff --git a/t/t_adler.c b/t/t_adler.c
index 2b78103..e1cf29b 100644
--- a/t/t_adler.c
+++ b/t/t_adler.c
@@ -32,7 +32,6 @@
 #include <sys/types.h>
 
 #include <stdint.h>
-#include <stdio.h>
 #include <string.h>
 
 #include <cryb/endian.h>
diff --git a/t/t_aes.c b/t/t_aes.c
index 2deed0c..25c8328 100644
--- a/t/t_aes.c
+++ b/t/t_aes.c
@@ -33,7 +33,6 @@
 
 #include <stdint.h>
 #include <stdio.h>
-#include <string.h>
 
 #include <cryb/aes.h>
 
diff --git a/t/t_endian.c b/t/t_endian.c
index 17913df..0c9d6b1 100644
--- a/t/t_endian.c
+++ b/t/t_endian.c
@@ -31,9 +31,8 @@
 
 #include <sys/types.h>
 
+#include <stddef.h>
 #include <stdint.h>
-#include <stdio.h>
-#include <string.h>
 
 /* test our own code, not the compiler's */
 #undef HAVE___BUILTIN_BSWAP16
diff --git a/t/t_fletcher.c b/t/t_fletcher.c
index f133749..adae8df 100644
--- a/t/t_fletcher.c
+++ b/t/t_fletcher.c
@@ -33,7 +33,6 @@
 
 #include <stdint.h>
 #include <stdio.h>
-#include <string.h>
 
 #include <cryb/endian.h>
 #include <cryb/hash.h>
diff --git a/t/t_rc4.c b/t/t_rc4.c
index c41abba..b950e83 100644
--- a/t/t_rc4.c
+++ b/t/t_rc4.c
@@ -32,7 +32,6 @@
 #include <sys/types.h>
 
 #include <stdint.h>
-#include <stdio.h>
 #include <string.h>
 
 #include <cryb/rc4.h>
diff --git a/t/t_rfc3986.c b/t/t_rfc3986.c
index f401862..9ab6d06 100644
--- a/t/t_rfc3986.c
+++ b/t/t_rfc3986.c
@@ -33,10 +33,7 @@
 
 #include <errno.h>
 #include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
 
 #include <cryb/rfc3986.h>
 
diff --git a/t/t_rfc4648.c b/t/t_rfc4648.c
index d6d9903..4a7088f 100644
--- a/t/t_rfc4648.c
+++ b/t/t_rfc4648.c
@@ -34,10 +34,7 @@
 
 #include <errno.h>
 #include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
 
 #include <cryb/rfc4648.h>
 
diff --git a/t/t_sha224.c b/t/t_sha224.c
index ebe195f..7c92a4c 100644
--- a/t/t_sha224.c
+++ b/t/t_sha224.c
@@ -178,7 +178,7 @@ t_sha224_short_updates(char **desc CRYB_UNUSED, void *arg)
 		sha224_update(&ctx, vector->msg + i, 5);
 	sha224_update(&ctx, vector->msg + i, len - i);
 	sha224_final(&ctx, digest);
-	return (memcmp(digest, vector->digest, SHA224_DIGEST_LEN) == 0);
+	return (t_compare_mem(digest, vector->digest, SHA224_DIGEST_LEN));
 }
 #endif
 
diff --git a/t/t_sha384.c b/t/t_sha384.c
index c6ac194..5003df9 100644
--- a/t/t_sha384.c
+++ b/t/t_sha384.c
@@ -189,7 +189,7 @@ t_sha384_short_updates(char **desc CRYB_UNUSED, void *arg)
 		sha384_update(&ctx, vector->msg + i, 5);
 	sha384_update(&ctx, vector->msg + i, len - i);
 	sha384_final(&ctx, digest);
-	return (memcmp(digest, vector->digest, SHA384_DIGEST_LEN) == 0);
+	return (t_compare_mem(digest, vector->digest, SHA384_DIGEST_LEN));
 }
 #endif
 
diff --git a/t/t_string.c b/t/t_string.c
index b980b68..b1d54ab 100644
--- a/t/t_string.c
+++ b/t/t_string.c
@@ -31,9 +31,8 @@
 
 #include <sys/types.h>
 
+#include <stddef.h>
 #include <stdint.h>
-#include <stdio.h>
-#include <string.h>
 
 #include <cryb/string.h>
 
diff --git a/t/t_strlcmp.c b/t/t_strlcmp.c
index 5a11b46..264f2e1 100644
--- a/t/t_strlcmp.c
+++ b/t/t_strlcmp.c
@@ -31,9 +31,8 @@
 
 #include <sys/types.h>
 
+#include <stddef.h>
 #include <stdint.h>
-#include <stdio.h>
-#include <string.h>
 
 #undef HAVE_STRLCMP
 #include <cryb/strlcmp.h>
diff --git a/t/t_wstring.c b/t/t_wstring.c
index e2cbdaa..4089a8a 100644
--- a/t/t_wstring.c
+++ b/t/t_wstring.c
@@ -31,9 +31,8 @@
 
 #include <sys/types.h>
 
+#include <stddef.h>
 #include <stdint.h>
-#include <stdio.h>
-#include <string.h>
 #include <wchar.h>
 
 #include <cryb/wstring.h>