test: add audio pass-through test with RMS validation

Co-authored-by: aider (deepseek/deepseek-reasoner) <aider@aider.chat>

tests/integration.c

@@ -180,6 +180,70 @@ static void test_clock_continue(void) {
     }
 }
 
+static int test_audio_pass_through(void) {
+    printf("Test: audio pass‑through (latency & RMS)\n");
+
+    /* check required tools */
+    if (system("which jack_sine >/dev/null 2>&1") != 0) {
+        fprintf(stderr, "  SKIP: jack_sine not installed\n");
+        return 1;
+    }
+    if (system("which jack_capture >/dev/null 2>&1") != 0) {
+        fprintf(stderr, "  SKIP: jack_capture not installed\n");
+        return 1;
+    }
+    if (system("which sox >/dev/null 2>&1") != 0) {
+        fprintf(stderr, "  SKIP: sox not installed\n");
+        return 1;
+    }
+    if (system("which python3 >/dev/null 2>&1") != 0) {
+        fprintf(stderr, "  SKIP: python3 not installed\n");
+        return 1;
+    }
+
+    pid_t pid = start_looper();
+    if (pid < 0) {
+        fprintf(stderr, "FAIL: could not start looper\n");
+        return 1;
+    }
+
+    /* connect sine generator to looper input */
+    if (system("jack_connect sine:output looper:input 2>/dev/null") != 0) {
+        fprintf(stderr, "FAIL: could not connect sine -> looper:input\n");
+        kill(pid, SIGTERM);
+        waitpid(pid, NULL, 0);
+        return 1;
+    }
+
+    /* capture 2 seconds of looper output */
+    system("jack_capture -d 2 -f /tmp/looper_test.wav 2>/dev/null");
+
+    /* compute RMS of captured WAV using Python */
+    int rms_ok = system(
+        "python3 -c '"
+        "import wave, math;"
+        "w=wave.open(\"/tmp/looper_test.wav\");"
+        "f=w.readframes(w.getnframes());"
+        "s=[int.from_bytes(f[i:i+2],\"little\",signed=True) for i in range(0,len(f),2)];"
+        "r=math.sqrt(sum(x*x for x in s)/len(s));"
+        "print(\"RMS=%%d\"%%r);"
+        "exit(0 if r>1000 else 1)'"
+        " 2>/dev/null"
+    );
+
+    /* clean up */
+    kill(pid, SIGTERM);
+    waitpid(pid, NULL, 0);
+
+    if (rms_ok == 0) {
+        printf("  PASS (RMS > 1000)\n");
+        return 0;
+    } else {
+        fprintf(stderr, "  FAIL: RMS too low or Python error\n");
+        return 1;
+    }
+}
+
 int main(void) {
     /* 1. binary must exist */
     if (system("test -x ./looper") != 0) {
@@ -204,6 +268,9 @@ int main(void) {
     test_clock_stop();
     test_clock_continue();
 
+    /* 5. Audio pass‑through test (optional tools) */
+    test_audio_pass_through();
+
     printf("All tests passed!\n");
     return 0;
 }