Tests: Mir needs the window to swap at lease 1 frame for the cursor to show. So render in testwm2

test/testwm2.c

@@ -50,6 +50,7 @@ quit(int rc)
 void
 loop()
 {
+    int i;
     SDL_Event event;
         /* Check for events */
         while (SDL_PollEvent(&event)) {
@@ -100,6 +101,12 @@ loop()
                 }
             }
         }
+
+        for (i = 0; i < state->num_windows; ++i) {
+            SDL_Renderer *renderer = state->renderers[i];
+            SDL_RenderClear(renderer);
+            SDL_RenderPresent(renderer);
+        }
 #ifdef __EMSCRIPTEN__
     if (done) {
         emscripten_cancel_main_loop();
@@ -122,7 +129,6 @@ main(int argc, char *argv[])
     if (!state) {
         return 1;
     }
-    state->skip_renderer = SDL_TRUE;
     for (i = 1; i < argc;) {
         int consumed;
 
@@ -140,6 +146,12 @@ main(int argc, char *argv[])
         quit(2);
     }
 
+    for (i = 0; i < state->num_windows; ++i) {
+        SDL_Renderer *renderer = state->renderers[i];
+        SDL_SetRenderDrawColor(renderer, 0xA0, 0xA0, 0xA0, 0xFF);
+        SDL_RenderClear(renderer);
+    }
+ 
     /* Main render loop */
     done = 0;
 #ifdef __EMSCRIPTEN__