added 3 surfaces with auto switching

surface_switching_test/main.py

@@ -0,0 +1,35 @@
+import pygame
+from surface_switching_test.surfaces import sf_1, sf_2, sf_3
+
+WINDOW_SIZE = (800, 600)
+
+VALID_SURFACES = [
+    'sf_1',
+    'sf_2',
+    'sf_3'
+]
+
+
+def main():
+    pygame.init()
+
+    window = pygame.display.set_mode(WINDOW_SIZE)
+
+    clock = pygame.time.Clock()
+
+    running = True
+    surface = globals()['sf_1'].Surface(WINDOW_SIZE)
+    while running:
+        clock.tick(15)
+        surface.update()
+        window.blit(surface, surface.get_rect())
+
+        if not surface.running:
+            next_surface = surface.next_surface
+            if next_surface not in VALID_SURFACES:
+                raise Exception('Given surface is not listed in valid surfaces!')
+            surface = globals()[next_surface].Surface(WINDOW_SIZE)
+
+        pygame.display.flip()
+
+    pygame.quit()