diff --git a/tests/suites/test_suite_cipher.chacha20.data b/tests/suites/test_suite_cipher.chacha20.data
index dfa0e76ad..11bbfa231 100644
--- a/tests/suites/test_suite_cipher.chacha20.data
+++ b/tests/suites/test_suite_cipher.chacha20.data
@@ -116,20 +116,20 @@ enc_dec_buf_multipart:MBEDTLS_CIPHER_CHACHA20:256:16:16:-1:16:16:16:16
 
 ChaCha20 IV Length 0
 depends_on:MBEDTLS_CHACHA20_C
-check_iv:MBEDTLS_CIPHER_CHACHA20:"CHACHA20":0:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
+iv_len_validity:MBEDTLS_CIPHER_CHACHA20:"CHACHA20":0:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
 
 ChaCha20 IV Length 11
 depends_on:MBEDTLS_CHACHA20_C
-check_iv:MBEDTLS_CIPHER_CHACHA20:"CHACHA20":11:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
+iv_len_validity:MBEDTLS_CIPHER_CHACHA20:"CHACHA20":11:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
 
 ChaCha20 IV Length 12
 depends_on:MBEDTLS_CHACHA20_C
-check_iv:MBEDTLS_CIPHER_CHACHA20:"CHACHA20":12:0
+iv_len_validity:MBEDTLS_CIPHER_CHACHA20:"CHACHA20":12:0
 
 ChaCha20 IV Length 13
 depends_on:MBEDTLS_CHACHA20_C
-check_iv:MBEDTLS_CIPHER_CHACHA20:"CHACHA20":13:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
+iv_len_validity:MBEDTLS_CIPHER_CHACHA20:"CHACHA20":13:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
 
 ChaCha20 IV Length 16
 depends_on:MBEDTLS_CHACHA20_C
-check_iv:MBEDTLS_CIPHER_CHACHA20:"CHACHA20":16:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
+iv_len_validity:MBEDTLS_CIPHER_CHACHA20:"CHACHA20":16:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
diff --git a/tests/suites/test_suite_cipher.chachapoly.data b/tests/suites/test_suite_cipher.chachapoly.data
index 908951a18..df7891792 100644
--- a/tests/suites/test_suite_cipher.chachapoly.data
+++ b/tests/suites/test_suite_cipher.chachapoly.data
@@ -124,20 +124,20 @@ decrypt_test_vec:MBEDTLS_CIPHER_CHACHA20_POLY1305:-1:"1c9240a5eb55d38af333888604
 
 ChaCha20+Poly1305 IV Length 0
 depends_on:MBEDTLS_CHACHAPOLY_C
-check_iv:MBEDTLS_CIPHER_CHACHA20_POLY1305:"CHACHA20-POLY1305":0:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
+iv_len_validity:MBEDTLS_CIPHER_CHACHA20_POLY1305:"CHACHA20-POLY1305":0:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
 
 ChaCha20+Poly1305 IV Length 11
 depends_on:MBEDTLS_CHACHAPOLY_C
-check_iv:MBEDTLS_CIPHER_CHACHA20_POLY1305:"CHACHA20-POLY1305":11:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
+iv_len_validity:MBEDTLS_CIPHER_CHACHA20_POLY1305:"CHACHA20-POLY1305":11:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
 
 ChaCha20+Poly1305 IV Length 12
 depends_on:MBEDTLS_CHACHAPOLY_C
-check_iv:MBEDTLS_CIPHER_CHACHA20_POLY1305:"CHACHA20-POLY1305":12:0
+iv_len_validity:MBEDTLS_CIPHER_CHACHA20_POLY1305:"CHACHA20-POLY1305":12:0
 
 ChaCha20+Poly1305 IV Length 13
 depends_on:MBEDTLS_CHACHAPOLY_C
-check_iv:MBEDTLS_CIPHER_CHACHA20_POLY1305:"CHACHA20-POLY1305":13:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
+iv_len_validity:MBEDTLS_CIPHER_CHACHA20_POLY1305:"CHACHA20-POLY1305":13:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
 
 ChaCha20+Poly1305 IV Length 16
 depends_on:MBEDTLS_CHACHAPOLY_C
-check_iv:MBEDTLS_CIPHER_CHACHA20_POLY1305:"CHACHA20-POLY1305":16:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
+iv_len_validity:MBEDTLS_CIPHER_CHACHA20_POLY1305:"CHACHA20-POLY1305":16:MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
diff --git a/tests/suites/test_suite_cipher.function b/tests/suites/test_suite_cipher.function
index 03c17331a..93bff1e02 100644
--- a/tests/suites/test_suite_cipher.function
+++ b/tests/suites/test_suite_cipher.function
@@ -1599,12 +1599,15 @@ void check_padding( int pad_mode, data_t * input, int ret, int dlen_check
 /* END_CASE */
 
 /* BEGIN_CASE */
-void check_iv( int cipher_id, char * cipher_string,
+void iv_len_validity( int cipher_id, char * cipher_string,
                int iv_len_val, int ret )
 {
     size_t iv_len = iv_len_val;
     unsigned char iv[16];
 
+    /* Initialise iv buffer */
+    memset( iv, 0, sizeof( iv ) );
+
     const mbedtls_cipher_info_t *cipher_info;
     mbedtls_cipher_context_t ctx_dec;
     mbedtls_cipher_context_t ctx_enc;
diff --git a/tests/suites/test_suite_md.function b/tests/suites/test_suite_md.function
index d918ce3b9..8cbdbe4c7 100644
--- a/tests/suites/test_suite_md.function
+++ b/tests/suites/test_suite_md.function
@@ -16,6 +16,7 @@ void mbedtls_md_process(  )
     unsigned char buf[150];
 
     mbedtls_md_init( &ctx );
+    memset( buf, 0, sizeof( buf ) );
 
     /*
      * Very minimal testing of mbedtls_md_process, just make sure the various