Check for passthrough in tests.

tests/mal_test_0.c

@@ -194,6 +194,8 @@ int do_playback_test(mal_backend backend)
             }
         }
         haveDevice = MAL_TRUE;
+
+        printf("    Is Passthrough: %s\n", (device.dsp.isPassthrough) ? "YES" : "NO");
     }
 
     printf("  Opening Decoder... ");