diff --git a/test/API/H5_api_test.c b/test/API/H5_api_test.c
index 8b300c0fb0b..42055b3434b 100644
--- a/test/API/H5_api_test.c
+++ b/test/API/H5_api_test.c
@@ -208,7 +208,9 @@ main(int argc, char **argv)
 
     snprintf(H5_api_test_filename, H5_API_TEST_FILENAME_MAX_LENGTH, "%s%s", test_path_prefix, TEST_FILE_NAME);
 
-    if (NULL == (vol_connector_string = getenv(HDF5_VOL_CONNECTOR))) {
+    vol_connector_string = getenv(HDF5_VOL_CONNECTOR);
+
+    if (!vol_connector_string || *vol_connector_string == '\0') {
         printf("No VOL connector selected; using native VOL connector\n");
         vol_connector_name = "native";
         vol_connector_info = NULL;
diff --git a/test/vol.c b/test/vol.c
index 368e6f44f38..82d49908396 100644
--- a/test/vol.c
+++ b/test/vol.c
@@ -2047,7 +2047,7 @@ test_async_vol_props(void)
 
     /* Override possible environment variable & re-initialize default VOL connector */
     conn_env_str = getenv(HDF5_VOL_CONNECTOR);
-    if (conn_env_str) {
+    if (conn_env_str && *conn_env_str) {
         if (NULL == (conn_env_str = strdup(conn_env_str)))
             TEST_ERROR;
         if (HDunsetenv(HDF5_VOL_CONNECTOR) < 0)
@@ -2292,7 +2292,7 @@ test_get_vol_name(void)
     TESTING("getting connector name");
 
     conn_env_str = getenv(HDF5_VOL_CONNECTOR);
-    if (NULL == (conn_env_str = getenv("HDF5_VOL_CONNECTOR")))
+    if (!conn_env_str || *conn_env_str == '\0')
         conn_env_str = "native";
 
     /* Skip the connectors other than the native and pass_through connector */
diff --git a/testpar/API/H5_api_test_parallel.c b/testpar/API/H5_api_test_parallel.c
index e1f217ee2d6..d9c675a31cd 100644
--- a/testpar/API/H5_api_test_parallel.c
+++ b/testpar/API/H5_api_test_parallel.c
@@ -296,7 +296,9 @@ main(int argc, char **argv)
     snprintf(H5_api_test_parallel_filename, H5_API_TEST_FILENAME_MAX_LENGTH, "%s%s", test_path_prefix,
              PARALLEL_TEST_FILE_NAME);
 
-    if (NULL == (vol_connector_string = getenv(HDF5_VOL_CONNECTOR))) {
+    vol_connector_string = getenv(HDF5_VOL_CONNECTOR);
+
+    if (!vol_connector_string || *vol_connector_string == '\0') {
         if (MAINPROCESS)
             printf("No VOL connector selected; using native VOL connector\n");
         vol_connector_name = "native";