Detach tone-test savers on reconnect

tonetest_test.go

@@ -24,3 +24,27 @@ func TestNewAudioFileSaverReportsUnavailableOutputPath(t *testing.T) {
 		t.Fatalf("got saver=%v err=%v", saver, err)
 	}
 }
+
+type testDetacher struct{ detached bool }
+
+func (d *testDetacher) Detach() { d.detached = true }
+
+// Regression: reconnecting tone-test mode kept prior savers attached to the
+// shared audio listener list, causing callbacks to write to closed files.
+func TestCleanupToneTestAudioDetachesSaver(t *testing.T) {
+	saver, err := NewAudioFileSaver(filepath.Join(t.TempDir(), "tone.pcm"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	detacher := &testDetacher{}
+	b := &Barnard{toneTestSaver: saver, toneTestSaverDetach: detacher}
+
+	b.cleanupToneTestAudio()
+	if !detacher.detached {
+		t.Fatal("tone saver listener was not detached")
+	}
+	if b.toneTestSaver != nil || b.toneTestSaverDetach != nil {
+		t.Fatal("tone saver cleanup retained connection state")
+	}
+	b.cleanupToneTestAudio()
+}