1 files changed, 96 insertions, 0 deletions
diff --git a/tests/test_segmenter.py b/tests/test_segmenter.py
new file mode 100644
index 0000000..d1f7ee5
--- /dev/null
+++ b/tests/test_segmenter.py
@@ -0,0 +1,96 @@
+from datetime import datetime, timedelta, timezone
+
+import numpy as np
+
+from mic_clipper.segmenter import Audio, End, Segmenter, Start
+
+
+SAMPLE_RATE = 16_000
+FRAME_SAMPLES = 512
+FRAME_DURATION = timedelta(seconds=FRAME_SAMPLES / SAMPLE_RATE)
+START = datetime(2026, 9, 29, 23, 59, 59, tzinfo=timezone.utc)
+
+
+def frame(value: float = 0.0) -> np.ndarray:
+    return np.full(FRAME_SAMPLES, value, dtype=np.float32)
+
+
+def push(segmenter: Segmenter, index: int, speech: bool, value: float = 0.0):
+    return segmenter.push(frame(value), speech, START + index * FRAME_DURATION)
+
+
+def test_speech_starts_segment_with_half_second_preroll():
+    segmenter = Segmenter(pre_roll_seconds=0.5, silence_seconds=1.5)
+
+    for index in range(16):
+        assert push(segmenter, index, False) == ()
+
+    events = push(segmenter, 16, True, 1.0)
+
+    assert len(events) == 1
+    assert isinstance(events[0], Start)
+    assert events[0].started_at == START + 16 * FRAME_DURATION - timedelta(seconds=0.5)
+    assert events[0].samples.shape == (8_512,)
+    assert np.all(events[0].samples[:8_000] == 0.0)
+    assert np.all(events[0].samples[8_000:] == 1.0)
+
+
+def test_short_silence_is_merged_into_active_segment():
+    segmenter = Segmenter(pre_roll_seconds=0.5, silence_seconds=1.5)
+
+    assert isinstance(push(segmenter, 0, True, 1.0)[0], Start)
+    assert isinstance(push(segmenter, 1, False)[0], Audio)
+    assert isinstance(push(segmenter, 2, True, 1.0)[0], Audio)
+    assert segmenter.active
+
+
+def test_one_point_five_seconds_of_silence_closes_segment():
+    segmenter = Segmenter(pre_roll_seconds=0.5, silence_seconds=1.5)
+
+    push(segmenter, 0, True, 1.0)
+    events = ()
+    for index in range(1, 48):
+        events = push(segmenter, index, False)
+
+    assert isinstance(events[0], Audio)
+    assert isinstance(events[-1], End)
+    assert not segmenter.active
+
+
+def test_maximum_segment_rolls_without_losing_audio():
+    segmenter = Segmenter(
+        pre_roll_seconds=0.5,
+        silence_seconds=1.5,
+        max_segment_seconds=FRAME_SAMPLES * 2 / SAMPLE_RATE,
+    )
+
+    first = push(segmenter, 0, True, 1.0)
+    second = push(segmenter, 1, True, 2.0)
+    third = push(segmenter, 2, True, 3.0)
+
+    assert isinstance(first[0], Start)
+    assert isinstance(second[0], Audio)
+    assert isinstance(third[0], End)
+    assert isinstance(third[1], Start)
+    assert np.all(third[1].samples == 3.0)
+
+
+def test_segment_start_date_is_retained_across_midnight():
+    segmenter = Segmenter(pre_roll_seconds=0.5, silence_seconds=1.5)
+
+    events = push(segmenter, 16, True, 1.0)
+
+    assert isinstance(events[0], Start)
+    assert events[0].started_at.date().isoformat() == "2026-09-29"
+
+
+def test_speech_after_a_closed_segment_keeps_terminal_silence_as_preroll():
+    segmenter = Segmenter(pre_roll_seconds=0.5, silence_seconds=1.5)
+
+    push(segmenter, 0, True, 1.0)
+    for index in range(1, 48):
+        push(segmenter, index, False)
+    events = push(segmenter, 48, True, 1.0)
+
+    assert isinstance(events[0], Start)
+    assert events[0].samples.shape == (8_512,)