Ruffification and fixed bug

tests/utils.py

@@ -4,35 +4,33 @@ import subprocess
 from subprocess import PIPE
 import json
 
-FFPROBE = 'ffprobe'
+FFPROBE = "ffprobe"
 
 
 def ffprobe(path):
-    arguments = [FFPROBE, "-of", "json", 
-                 "-show_format", "-show_streams", path]
-    if int(sys.version[0]) <  3:
+    arguments = [FFPROBE, "-of", "json", "-show_format", "-show_streams", path]
+    if int(sys.version[0]) < 3:
         process = subprocess.Popen(arguments, stdout=PIPE)
         process.wait()
         if process.returncode == 0:
             output = process.communicate()[0]
             if output:
-                output_str = output.decode('utf-8')
+                output_str = output.decode("utf-8")
                 return json.loads(output_str)
         else:
             return None
-    else: 
-        process = subprocess.run(arguments, stdin=None, 
-                                 stdout=PIPE, stderr=PIPE)
+    else:
+        process = subprocess.run(arguments, stdin=None, stdout=PIPE, stderr=PIPE)
         if process.returncode == 0:
-            output_str = process.stdout.decode('utf-8')
+            output_str = process.stdout.decode("utf-8")
             return json.loads(output_str)
         else:
             return None
 
 
 def all_files():
-    for dirpath, _, filenames in os.walk('tests/test_files'):
+    for dirpath, _, filenames in os.walk("tests/test_files"):
         for filename in filenames:
             _, ext = os.path.splitext(filename)
-            if ext in ['.wav', '.WAV']:
+            if ext in [".wav", ".WAV"]:
                 yield os.path.join(dirpath, filename)