Implement audio normalization and trimming functions

- Normalize audio to the range [-1, 1]
- Trim silence from audio
- Add test cases for both functions

tests/test_preprocessing.py

@@ -0,0 +1,20 @@
+import pytest
+import librosa
+from src.preprocessing.normalize import normalize_audio
+from src.preprocessing.trim import trim_audio
+from src.input.file_reader import read_audio
+
+def test_normalize_audio():
+    file_path = "samples/cafe_crowd_talk.aiff"
+    audio, _ = read_audio(file_path)
+    normalized_audio = normalize_audio(audio)
+
+    assert normalized_audio.max() <= 1.0
+    assert normalized_audio.min() >= -1.0
+
+def test_trim_audio():
+    file_path = "samples/cafe_crowd_talk.aiff"
+    audio, sr = read_audio(file_path)
+    trimmed_audio = trim_audio(audio, sr)
+
+    assert len(trimmed_audio) <= len(audio)