diff --git a/tests/display-test.c b/tests/display-test.c
index c2def44..89606c7 100644
--- a/tests/display-test.c
+++ b/tests/display-test.c
@@ -924,7 +924,7 @@ TEST(versions)
 }
 
 static void
-check_error_on_destroyed_object(void *data)
+check_error_on_destroyed_object(void)
 {
 	struct client *c;
 	struct wl_seat *seat;
@@ -1043,7 +1043,7 @@ TEST(filtered_global_is_hidden)
 		      1, d, bind_data_offer);
 	wl_display_set_global_filter(d->wl_display, global_filter, NULL);
 
-	client_create_noarg(d, get_globals);
+	client_create(d, get_globals, NULL);
 	display_run(d);
 
 	wl_global_destroy(g);
@@ -1052,13 +1052,13 @@ TEST(filtered_global_is_hidden)
 }
 
 static void
-get_dynamic_globals(void *data)
+get_dynamic_globals(void)
 {
 	struct client *c = client_connect();
 	struct wl_registry *registry;
 
 	registry = wl_display_get_registry(c->wl_display);
-	wl_registry_add_listener(registry, &registry_listener_filtered, data);
+	wl_registry_add_listener(registry, &registry_listener_filtered, NULL);
 	wl_display_roundtrip(c->wl_display);
 
 	/* Wait for the server to create a new global */
@@ -1206,7 +1206,7 @@ static const struct wl_registry_listener zombie_fd_registry_listener = {
 };
 
 static void
-zombie_client(void *data)
+zombie_client(void)
 {
 	struct client *c = client_connect();
 	struct wl_registry *registry;
@@ -1376,7 +1376,7 @@ static const struct wl_registry_listener double_zombie_fd_registry_listener = {
 };
 
 static void
-double_zombie_client(void *data)
+double_zombie_client(void)
 {
 	struct client *c = client_connect();
 	struct wl_registry *registry;
@@ -1436,7 +1436,7 @@ static const struct wl_registry_listener bind_interface_mismatch_registry_listen
 };
 
 static void
-registry_bind_interface_mismatch_client(void *data)
+registry_bind_interface_mismatch_client(void)
 {
 	struct client *c = client_connect();
 	struct wl_registry *registry;
@@ -1598,7 +1598,7 @@ static const struct wl_registry_listener global_remove_before_registry_listener
 };
 
 static void
-global_remove_before_client(void *data)
+global_remove_before_client(void)
 {
 	struct client *c = client_connect();
 	struct wl_registry *registry;
@@ -1648,7 +1648,7 @@ static const struct wl_registry_listener global_remove_after_registry_listener =
 };
 
 static void
-global_remove_after_client(void *data)
+global_remove_after_client(void)
 {
 	struct client *c = client_connect();
 	struct wl_registry *registry;
diff --git a/tests/test-compositor.c b/tests/test-compositor.c
index 8648fb6..8ec0631 100644
--- a/tests/test-compositor.c
+++ b/tests/test-compositor.c
@@ -507,7 +507,7 @@ static const struct wl_registry_listener registry_listener =
 	NULL
 };
 
-struct client *client_connect()
+struct client *client_connect(void)
 {
 	struct wl_registry *reg;
 	struct client *c = calloc(1, sizeof *c);
diff --git a/tests/test-compositor.h b/tests/test-compositor.h
index 3fb390c..662a81c 100644
--- a/tests/test-compositor.h
+++ b/tests/test-compositor.h
@@ -118,5 +118,17 @@ struct client_info *client_create_with_name(struct display *d,
 					    void *data,
 					    const char *name);
 #define client_create(d, c, data) client_create_with_name((d), (c), data, (#c))
+static inline void noarg_cb(void *data)
+{
+	void (*cb)(void) = data;
+	cb();
+}
+static inline struct client_info *client_create_with_name_noarg(struct display *d,
+								void (*client_main)(void),
+								const char *name)
+{
+	return client_create_with_name(d, noarg_cb, client_main, name);
+}
+
 #define client_create_noarg(d, c) \
-	client_create_with_name((d), (void(*)(void *)) (c), NULL, (#c))
+	client_create_with_name_noarg((d), (c), (#c))