Add basic I/O test for sigmf_convert_wav (fixes #50) (#123)

* Add basic I/O test for sigmf_convert_wav (fixes #50)
* black & isort

---------

Co-authored-by: Kyle A Logue <kyle.a.logue@aero.org>

Author: aic1994

tests/test_convert_wav.py

@@ -0,0 +1,46 @@
+# Copyright: Multiple Authors
+#
+# This file is part of sigmf-python. https://github.com/sigmf/sigmf-python
+#
+# SPDX-License-Identifier: LGPL-3.0-or-later
+
+"""Tests wav formatted audio conversion"""
+
+import os
+import tempfile
+
+import numpy as np
+import pytest
+from scipy.io import wavfile
+
+from sigmf.apps.convert_wav import convert_wav
+
+
+def test_wav_to_sigmf_basic():
+    """Basic smoke-test: convert a tiny WAV → SIGMF, assert file created."""
+    fs = 48_000
+    t = np.linspace(0, 0.1, int(fs * 0.1))  # 0.1 s
+    sine = np.sin(2 * np.pi * 1000 * t)
+    sine_int = (sine * 32767).astype(np.int16)
+
+    # Create temp file and close it before use
+    with tempfile.NamedTemporaryFile(suffix=".wav", delete=False) as tmp_wav:
+        tmp_wav_path = tmp_wav.name
+
+    # Write to the closed file
+    wavfile.write(tmp_wav_path, fs, sine_int)
+    tmp_sigmf = tmp_wav_path.replace(".wav", ".sigmf")
+
+    try:
+        # Run converter
+        convert_wav(tmp_wav_path, tmp_sigmf)
+
+        # Assert SIGMF file exists and non-zero
+        assert os.path.exists(tmp_sigmf), "SIGMF file not created"
+        assert os.path.getsize(tmp_sigmf) > 0, "SIGMF file is empty"
+    finally:
+        # Clean up both files
+        if os.path.exists(tmp_wav_path):
+            os.remove(tmp_wav_path)
+        if os.path.exists(tmp_sigmf):
+            os.remove(tmp_sigmf)