--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dictation/audio_test.py	Mon Aug 17 10:58:47 2026 -0700
@@ -0,0 +1,50 @@
+import unittest
+
+import numpy as np
+
+from dictation.audio import AudioEventKind, AudioSegmenter
+
+
+class AudioSegmenterTest(unittest.TestCase):
+    def test_emits_partial_and_final_events(self):
+        segmenter = AudioSegmenter(
+            sample_rate=1000,
+            speech_threshold=0.01,
+            silence_ms=200,
+            partial_interval_ms=500,
+            max_utterance_seconds=5,
+            pre_roll_ms=100,
+        )
+        silence = np.zeros(100, dtype=np.float32)
+        speech = np.full(250, 0.2, dtype=np.float32)
+
+        self.assertEqual(segmenter.feed(silence), [])
+        events = segmenter.feed(speech)
+        self.assertEqual(events[0].kind, AudioEventKind.SPEECH_STARTED)
+        events = segmenter.feed(speech)
+        self.assertIn(AudioEventKind.PARTIAL_READY, [event.kind for event in events])
+        events = segmenter.feed(np.zeros(200, dtype=np.float32))
+        self.assertEqual(events[-1].kind, AudioEventKind.FINAL_READY)
+        self.assertFalse(segmenter.speaking)
+
+    def test_max_duration_bounds_utterance(self):
+        segmenter = AudioSegmenter(
+            sample_rate=100,
+            speech_threshold=0.01,
+            silence_ms=500,
+            partial_interval_ms=10000,
+            max_utterance_seconds=3,
+            pre_roll_ms=0,
+        )
+        events = []
+        for _ in range(3):
+            events.extend(
+                segmenter.feed(np.full(100, 0.2, dtype=np.float32))
+            )
+        final = [event for event in events if event.kind == AudioEventKind.FINAL_READY]
+        self.assertEqual(len(final), 1)
+        self.assertLessEqual(final[0].samples.size, 300)
+
+
+if __name__ == "__main__":
+    unittest.main()