diff --git a/tests/suites/test_suite_blowfish.function b/tests/suites/test_suite_blowfish.function
index 028ae1a..1d1422a 100644
--- a/tests/suites/test_suite_blowfish.function
+++ b/tests/suites/test_suite_blowfish.function
@@ -12,6 +12,9 @@
 {
     mbedtls_blowfish_context ctx;
     unsigned char buf[16] = { 0 };
+    size_t const valid_keylength = sizeof( buf ) * 8;
+    size_t valid_mode = MBEDTLS_BLOWFISH_ENCRYPT;
+    size_t invalid_mode = 42;
     size_t off;
     ((void) off);
 
@@ -21,53 +24,53 @@
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_setkey( NULL,
                                                      buf,
-                                                     128 ) );
+                                                     valid_keylength ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_setkey( &ctx,
                                                      NULL,
-                                                     128 ) );
+                                                     valid_keylength ) );
 
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_ecb( NULL,
-                                                     MBEDTLS_BLOWFISH_ENCRYPT,
+                                                     valid_mode,
                                                      buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_ecb( &ctx,
-                                                        42,
+                                                        invalid_mode,
                                                         buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_ecb( &ctx,
-                                                        MBEDTLS_BLOWFISH_ENCRYPT,
+                                                        valid_mode,
                                                         NULL, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_ecb( &ctx,
-                                                        MBEDTLS_BLOWFISH_ENCRYPT,
+                                                        valid_mode,
                                                         buf, NULL ) );
 
 #if defined(MBEDTLS_CIPHER_MODE_CBC)
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cbc( NULL,
-                                                        MBEDTLS_BLOWFISH_ENCRYPT,
+                                                        valid_mode,
                                                         sizeof( buf ),
                                                         buf, buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cbc( &ctx,
-                                                        42,
+                                                        invalid_mode,
                                                         sizeof( buf ),
                                                         buf, buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cbc( &ctx,
-                                                        MBEDTLS_BLOWFISH_ENCRYPT,
+                                                        valid_mode,
                                                         sizeof( buf ),
                                                         NULL, buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cbc( &ctx,
-                                                        MBEDTLS_BLOWFISH_ENCRYPT,
+                                                        valid_mode,
                                                         sizeof( buf ),
                                                         buf, NULL, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cbc( &ctx,
-                                                        MBEDTLS_BLOWFISH_ENCRYPT,
+                                                        valid_mode,
                                                         sizeof( buf ),
                                                         buf, buf, NULL ) );
 #endif /* MBEDTLS_CIPHER_MODE_CBC */
@@ -75,37 +78,37 @@
 #if defined(MBEDTLS_CIPHER_MODE_CFB)
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cfb64( NULL,
-                                                          MBEDTLS_BLOWFISH_ENCRYPT,
+                                                          valid_mode,
                                                           sizeof( buf ),
                                                           &off, buf,
                                                           buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cfb64( &ctx,
-                                                          42,
+                                                          invalid_mode,
                                                           sizeof( buf ),
                                                           &off, buf,
                                                           buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cfb64( &ctx,
-                                                          MBEDTLS_BLOWFISH_ENCRYPT,
+                                                          valid_mode,
                                                           sizeof( buf ),
                                                           NULL, buf,
                                                           buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cfb64( &ctx,
-                                                          MBEDTLS_BLOWFISH_ENCRYPT,
+                                                          valid_mode,
                                                           sizeof( buf ),
                                                           &off, NULL,
                                                           buf, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cfb64( &ctx,
-                                                          MBEDTLS_BLOWFISH_ENCRYPT,
+                                                          valid_mode,
                                                           sizeof( buf ),
                                                           &off, buf,
                                                           NULL, buf ) );
     TEST_INVALID_PARAM_RET( MBEDTLS_ERR_BLOWFISH_BAD_INPUT_DATA,
                             mbedtls_blowfish_crypt_cfb64( &ctx,
-                                                          MBEDTLS_BLOWFISH_ENCRYPT,
+                                                          valid_mode,
                                                           sizeof( buf ),
                                                           &off, buf,
                                                           buf, NULL ) );