Fix audio type conversion (#259)

* Fix conversion between audio dtypes

* Run Pytest in CI

* Add pytest tests path in pyproject.toml

* Fix usages

* Use other PR's test format (more or less)

* Support legacy arguments

* Fix pyproject.toml and test location

* Omit `test` arg in CI, given by pyproject.toml

---------

Co-authored-by: Freddy Boulton <alfonsoboulton@gmail.com>

test/test_utils.py

@@ -0,0 +1,61 @@
+import numpy as np
+import pytest
+from fastrtc.utils import audio_to_float32, audio_to_int16
+
+
+def test_audio_to_float32_valid_int16():
+    audio = np.array([-32768, 0, 32767], dtype=np.int16)
+    expected = np.array([-1.0, 0.0, 32767 / 32768.0], dtype=np.float32)
+    result = audio_to_float32(audio)
+    np.testing.assert_array_almost_equal(result, expected)
+
+
+def test_audio_to_float32_valid_float32():
+    audio = np.array([-1.0, 0.0, 1.0], dtype=np.float32)
+    result = audio_to_float32(audio)
+    np.testing.assert_array_equal(result, audio)
+
+
+def test_audio_to_float32_empty_array():
+    audio = np.array([], dtype=np.int16)
+    result = audio_to_float32(audio)
+    np.testing.assert_array_equal(result, np.array([], dtype=np.float32))
+
+
+def test_audio_to_float32_invalid_dtype():
+    audio = np.array([1, 2, 3], dtype=np.int32)
+    with pytest.raises(TypeError, match="Unsupported audio data type"):
+        audio_to_float32(audio)  # type: ignore
+
+
+def test_audio_to_int16_valid_float32():
+    audio = np.array([-1.0, 0.0, 1.0], dtype=np.float32)
+    expected = np.array([-32767, 0, 32767], dtype=np.int16)
+    result = audio_to_int16(audio)
+    np.testing.assert_array_equal(result, expected)
+
+
+def test_audio_to_int16_valid_int16():
+    audio = np.array([-32768, 0, 32767], dtype=np.int16)
+    result = audio_to_int16(audio)
+    np.testing.assert_array_equal(result, audio)
+
+
+def test_audio_to_int16_empty_array():
+    audio = np.array([], dtype=np.float32)
+    result = audio_to_int16(audio)
+    np.testing.assert_array_equal(result, np.array([], dtype=np.int16))
+
+
+def test_audio_to_int16_invalid_dtype():
+    audio = np.array([1, 2, 3], dtype=np.int32)
+    with pytest.raises(TypeError, match="Unsupported audio data type"):
+        audio_to_int16(audio)  # type: ignore
+
+
+def test_legacy_arguments():
+    result = audio_to_float32((16000, np.zeros(10, dtype=np.int16)))
+    np.testing.assert_array_equal(result, np.zeros(10, dtype=np.float32))
+
+    result = audio_to_int16((16000, np.zeros(10, dtype=np.float32)))
+    np.testing.assert_array_equal(result, np.zeros(10, dtype=np.int16))