add audio test file

tests/sdl_audio.c

@@ -0,0 +1,38 @@
+#include <stdio.h>
+#include <SDL/SDL.h>
+#include <SDL/SDL_mixer.h>
+#include <assert.h>
+#include <emscripten.h>
+
+Mix_Chunk *sound;
+
+void play() {
+  int channel = Mix_PlayChannel(-1, sound, 1);
+  assert(channel >= 0);
+}
+
+int main() {
+  SDL_Init(SDL_INIT_AUDIO);
+
+  int ret = Mix_OpenAudio(0, 0, 0, 0); // we ignore all these..
+  assert(ret == 0);
+
+  sound = Mix_LoadWAV("sound.ogg");
+  assert(sound);
+
+  play();
+
+  emscripten_run_script("element = document.createElement('input');"
+                        "element.setAttribute('type', 'button');"
+                        "element.setAttribute('value', 'replay!');"
+                        "element.setAttribute('onclick', '_play()');"
+                        "document.body.appendChild(element);");
+
+  printf("you should hear a victory sound. press the button to replay!\n");
+
+  int result = 1;
+  REPORT_RESULT();
+
+  return 0;
+}
+