Add comment and tighten sox testing spec

Author: samanklesaria

.github/scripts/unittest-linux/run_test.sh

@@ -30,5 +30,5 @@ fi
 
 (
     cd test
-    pytest torchaudio_unittest -k "not backend and not /io/ and not prototype and not ffmpeg and not fairseq and not hdemucs and not (torchscript and rnnt) and not torchscript_consistency"
+    pytest torchaudio_unittest -k "not backend and not (sox and not compatibility) and not /io/ and not prototype and not ffmpeg and not fairseq and not hdemucs and not (torchscript and rnnt) and not torchscript_consistency"
 )

src/torchaudio/_internal/module_utils.py

@@ -97,6 +97,8 @@ def decorator(func):
     {func.__doc__}
     """
 
+        # This is a temporary fix to avoid depending on sox during testing.
+        # It will be removed once the sox dependency is removed from the rest of the codebase.
         if 'sox' not in func.__module__:
             UNSUPPORTED.append(wrapped)
         return wrapped