diff --git a/compositor/weston.h b/compositor/weston.h
index aadb80b5..26807203 100644
--- a/compositor/weston.h
+++ b/compositor/weston.h
@@ -98,12 +98,6 @@ text_backend_destroy(struct text_backend *text_backend);
 int
 wet_main(int argc, char *argv[], const struct weston_testsuite_data *test_data);
 
-
-/* test suite utilities */
-
-/** Opaque type for a test suite to define. */
-struct wet_testsuite_data;
-
 #ifdef  __cplusplus
 }
 #endif
diff --git a/include/libweston/libweston.h b/include/libweston/libweston.h
index 6a900ef1..101b2b72 100644
--- a/include/libweston/libweston.h
+++ b/include/libweston/libweston.h
@@ -203,7 +203,7 @@ struct weston_testsuite_quirks {
  */
 struct weston_testsuite_data {
 	struct weston_testsuite_quirks test_quirks;
-	struct wet_testsuite_data *test_private_data;
+	void *test_private_data;
 };
 
 /** Represents a head, usually a display connector
diff --git a/libweston/compositor.c b/libweston/compositor.c
index 9e91cdf8..64342592 100644
--- a/libweston/compositor.c
+++ b/libweston/compositor.c
@@ -7334,9 +7334,9 @@ debug_scene_graph_cb(struct weston_log_subscription *sub, void *data)
  *  1. The struct weston_testsuite_quirks, which can be used by the tests to
  *  change certain behavior of Weston when running these tests.
  *
- *  2. The struct wet_testsuite_data member, which can be used by the test suite
+ *  2. The void *test_private_data member which can be used by the test suite
  *  of projects that uses libweston in order to give arbitrary test data to the
- *  compositor.
+ *  compositor. Its type should be defined by the test suite of the project.
  *
  * This function can be called at most once per compositor instance, just after
  * creating the weston_compositor object and never again. This happens because