If there a test for appendicitis, like pushing on your belly or something?

Yes. If you have acute abdominal pain and a fever, go the emergency room or your doctor and they will examine you and take a blood test. When they push on your abdomen, they will look for a "rebound" sign or if you have tenderness on the right. If the doctor thinks you have appendicitis, they will order a ct scan of the abdomen and pelvis which is extremely sensitive at detecting acute appendicitis.