feat: add recorder module with sounddevice audio capture

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/test_recorder.py

@@ -0,0 +1,65 @@
+import numpy as np
+import pytest
+from unittest.mock import MagicMock, patch
+
+from whisper_local.recorder import Recorder
+
+
+@pytest.fixture
+def recorder():
+    return Recorder(sample_rate=16000, channels=1, min_duration=0.5)
+
+
+class TestRecorder:
+    def test_init(self, recorder):
+        assert recorder.sample_rate == 16000
+        assert recorder.channels == 1
+        assert not recorder.is_recording
+
+    def test_start_recording(self, recorder):
+        with patch("sounddevice.InputStream") as mock_stream_cls:
+            mock_stream = MagicMock()
+            mock_stream_cls.return_value = mock_stream
+            recorder.start()
+            assert recorder.is_recording
+            assert len(recorder._chunks) == 0
+            recorder.stop()  # Cleanup
+
+    def test_stop_without_start_returns_none(self, recorder):
+        result = recorder.stop()
+        assert result is None
+
+    def test_add_chunk_and_stop(self, recorder):
+        with patch("sounddevice.InputStream") as mock_stream_cls:
+            mock_stream_cls.return_value = MagicMock()
+            recorder.start()
+            # Simuliere 1 Sekunde Audio (16000 Samples)
+            chunk = np.zeros((16000, 1), dtype=np.float32)
+            recorder._chunks.append(chunk)
+            result = recorder.stop()
+        assert result is not None
+        assert result.shape == (16000,)
+        assert result.dtype == np.float32
+
+    def test_short_audio_returns_none(self, recorder):
+        with patch("sounddevice.InputStream") as mock_stream_cls:
+            mock_stream_cls.return_value = MagicMock()
+            recorder.start()
+            # Nur 0.1s Audio — unter min_duration
+            chunk = np.zeros((1600, 1), dtype=np.float32)
+            recorder._chunks.append(chunk)
+            result = recorder.stop()
+        assert result is None
+
+    def test_multiple_chunks_concatenated(self, recorder):
+        with patch("sounddevice.InputStream") as mock_stream_cls:
+            mock_stream_cls.return_value = MagicMock()
+            recorder.start()
+            chunk1 = np.ones((8000, 1), dtype=np.float32)
+            chunk2 = np.ones((8000, 1), dtype=np.float32) * 0.5
+            recorder._chunks.extend([chunk1, chunk2])
+            result = recorder.stop()
+        assert result is not None
+        assert result.shape == (16000,)
+        assert result[0] == 1.0
+        assert result[8000] == 0.5