diff --git a/tests/suites/test_suite_md.function b/tests/suites/test_suite_md.function
index d0f08e1..a499ca0 100644
--- a/tests/suites/test_suite_md.function
+++ b/tests/suites/test_suite_md.function
@@ -131,17 +131,15 @@
 /* BEGIN_CASE */
 void md_text(int md_type, char *text_src_string, data_t *hash)
 {
-    unsigned char src_str[1000];
+    unsigned char *src = (unsigned char *) text_src_string;
+    size_t src_len = strlen(text_src_string);
     unsigned char output[MBEDTLS_MD_MAX_SIZE] = {0};
     const mbedtls_md_info_t *md_info = NULL;
 
-    memset(src_str, 0x00, 1000);
-
-    strncpy((char *) src_str, text_src_string, sizeof(src_str) - 1);
     md_info = mbedtls_md_info_from_type(md_type);
     TEST_ASSERT(md_info != NULL);
 
-    TEST_ASSERT(0 == mbedtls_md(md_info, src_str, strlen((char *) src_str), output));
+    TEST_ASSERT(0 == mbedtls_md(md_info, src, src_len, output));
 
     TEST_ASSERT(mbedtls_test_hexcmp(output, hash->x,
                                     mbedtls_md_get_size(md_info),
@@ -171,9 +169,10 @@
 void md_text_multi(int md_type, char *text_src_string,
                    data_t *hash)
 {
-    unsigned char src_str[1000];
+    unsigned char *src = (unsigned char *) text_src_string;
+    size_t src_len = strlen(text_src_string);
     unsigned char output[MBEDTLS_MD_MAX_SIZE] = {0};
-    int halfway, len;
+    size_t halfway;
 
     const mbedtls_md_info_t *md_info = NULL;
     mbedtls_md_context_t ctx, ctx_copy;
@@ -181,11 +180,7 @@
     mbedtls_md_init(&ctx);
     mbedtls_md_init(&ctx_copy);
 
-    memset(src_str, 0x00, 1000);
-
-    strncpy((char *) src_str, text_src_string, sizeof(src_str) - 1);
-    len = strlen((char *) src_str);
-    halfway = len / 2;
+    halfway = src_len / 2;
 
     md_info = mbedtls_md_info_from_type(md_type);
     TEST_ASSERT(md_info != NULL);
@@ -194,10 +189,10 @@
 
     TEST_ASSERT(0 == mbedtls_md_starts(&ctx));
     TEST_ASSERT(ctx.md_ctx != NULL);
-    TEST_ASSERT(0 == mbedtls_md_update(&ctx, src_str, halfway));
+    TEST_ASSERT(0 == mbedtls_md_update(&ctx, src, halfway));
     TEST_ASSERT(0 == mbedtls_md_clone(&ctx_copy, &ctx));
 
-    TEST_ASSERT(0 == mbedtls_md_update(&ctx, src_str + halfway, len - halfway));
+    TEST_ASSERT(0 == mbedtls_md_update(&ctx, src + halfway, src_len - halfway));
     TEST_ASSERT(0 == mbedtls_md_finish(&ctx, output));
     TEST_ASSERT(mbedtls_test_hexcmp(output, hash->x,
                                     mbedtls_md_get_size(md_info),
@@ -206,7 +201,7 @@
     /* Test clone */
     memset(output, 0x00, sizeof(output));
 
-    TEST_ASSERT(0 == mbedtls_md_update(&ctx_copy, src_str + halfway, len - halfway));
+    TEST_ASSERT(0 == mbedtls_md_update(&ctx_copy, src + halfway, src_len - halfway));
     TEST_ASSERT(0 == mbedtls_md_finish(&ctx_copy, output));
     TEST_ASSERT(mbedtls_test_hexcmp(output, hash->x,
                                     mbedtls_md_get_size(md_info),