diff --git a/test/default/cmptest.h b/test/default/cmptest.h
index 6f5bebe4..4625d551 100644
--- a/test/default/cmptest.h
+++ b/test/default/cmptest.h
@@ -35,7 +35,7 @@
 
 int xmain(void);
 
-static void *guard_page;
+static unsigned char *guard_page;
 
 #ifdef BENCHMARKS
 
@@ -167,9 +167,9 @@ static FILE *fp_res;
 
 int main(void)
 {
-    FILE *fp_out;
-    void *_guard_page;
-    int   c;
+    FILE          *fp_out;
+    unsigned char *_guard_page;
+    int           c;
 
     if ((fp_res = fopen(TEST_NAME_RES, "w+")) == NULL) {
         perror("fopen(" TEST_NAME_RES ")");
@@ -178,11 +178,11 @@ int main(void)
     if (sodium_init() != 0) {
         return 99;
     }
-    if ((_guard_page = sodium_malloc(0)) == NULL) {
+    if ((_guard_page = (unsigned char *) sodium_malloc(0)) == NULL) {
         perror("sodium_malloc()");
         return 99;
     }
-    guard_page = (void *) (((unsigned char *) _guard_page) + 1);
+    guard_page = _guard_page + 1;
     if (xmain() != 0) {
         return 99;
     }
diff --git a/test/default/misuse.c b/test/default/misuse.c
index 8767c5e9..407d526f 100644
--- a/test/default/misuse.c
+++ b/test/default/misuse.c
@@ -45,7 +45,8 @@ sigabrt_handler_12(int sig)
 # else
     signal(SIGABRT, sigabrt_handler_13);
 # endif
-    assert(crypto_pwhash_str_alg(guard_page, "", 0U, 1U, 1U, -1) == -1);
+    assert(crypto_pwhash_str_alg((char *) guard_page,
+                                 "", 0U, 1U, 1U, -1) == -1);
     exit(1);
 }
 
@@ -76,7 +77,7 @@ sigabrt_handler_9(int sig)
 {
     (void) sig;
     signal(SIGABRT, sigabrt_handler_10);
-    assert(sodium_base642bin(guard_page, 1, guard_page, 1,
+    assert(sodium_base642bin(guard_page, 1, (const char *) guard_page, 1,
                              NULL, NULL, NULL, -1) == -1);
     exit(1);
 }
@@ -86,7 +87,7 @@ sigabrt_handler_8(int sig)
 {
     (void) sig;
     signal(SIGABRT, sigabrt_handler_9);
-    assert(sodium_bin2base64(guard_page, 1, guard_page, 1,
+    assert(sodium_bin2base64((char *) guard_page, 1, guard_page, 1,
                              sodium_base64_VARIANT_ORIGINAL) == NULL);
     exit(1);
 }
@@ -96,7 +97,8 @@ sigabrt_handler_7(int sig)
 {
     (void) sig;
     signal(SIGABRT, sigabrt_handler_8);
-    assert(sodium_bin2base64(guard_page, 1, guard_page, 1, -1) == NULL);
+    assert(sodium_bin2base64((char *) guard_page, 1,
+                             guard_page, 1, -1) == NULL);
     exit(1);
 }
 
diff --git a/test/default/pwhash_argon2id.c b/test/default/pwhash_argon2id.c
index f4e7450f..95463492 100644
--- a/test/default/pwhash_argon2id.c
+++ b/test/default/pwhash_argon2id.c
@@ -480,19 +480,19 @@ main(void)
     assert(crypto_pwhash_alg_argon2id13() != crypto_pwhash_alg_argon2i13());
     assert(crypto_pwhash_alg_argon2id13() == crypto_pwhash_alg_default());
 
-    assert(crypto_pwhash_argon2id(guard_page, 0, guard_page, 0, guard_page,
+    assert(crypto_pwhash_argon2id(guard_page, 0, (const char *) guard_page, 0, guard_page,
                                   crypto_pwhash_argon2id_OPSLIMIT_INTERACTIVE,
                                   crypto_pwhash_argon2id_MEMLIMIT_INTERACTIVE,
                                   0) == -1);
-    assert(crypto_pwhash_argon2id(guard_page, 0, guard_page, 0, guard_page,
+    assert(crypto_pwhash_argon2id(guard_page, 0, (const char *) guard_page, 0, guard_page,
                                  crypto_pwhash_argon2id_OPSLIMIT_INTERACTIVE,
                                  crypto_pwhash_argon2id_MEMLIMIT_INTERACTIVE,
                                  crypto_pwhash_ALG_ARGON2I13) == -1);
-    assert(crypto_pwhash_argon2i(guard_page, 0, guard_page, 0, guard_page,
+    assert(crypto_pwhash_argon2i(guard_page, 0, (const char *) guard_page, 0, guard_page,
                                  crypto_pwhash_argon2id_OPSLIMIT_INTERACTIVE,
                                  crypto_pwhash_argon2id_MEMLIMIT_INTERACTIVE,
                                  0) == -1);
-    assert(crypto_pwhash_argon2i(guard_page, 0, guard_page, 0, guard_page,
+    assert(crypto_pwhash_argon2i(guard_page, 0, (const char *) guard_page, 0, guard_page,
                                  crypto_pwhash_argon2id_OPSLIMIT_INTERACTIVE,
                                  crypto_pwhash_argon2id_MEMLIMIT_INTERACTIVE,
                                  crypto_pwhash_ALG_ARGON2ID13) == -1);