fixed : Divide by zero error came when string was empty, also a test

netlib/strutils.py

@@ -121,6 +121,9 @@ def escaped_str_to_bytes(data):
 
 def is_mostly_bin(s):
     # type: (bytes) -> bool
+    if not s or len(s) == 0:
+        return False
+
     return sum(
         i < 9 or 13 < i < 32 or 126 < i
         for i in six.iterbytes(s[:100])

test/netlib/test_strutils.py

@@ -85,7 +85,7 @@ def test_escaped_str_to_bytes():
 def test_is_mostly_bin():
     assert not strutils.is_mostly_bin(b"foo\xFF")
     assert strutils.is_mostly_bin(b"foo" + b"\xFF" * 10)
-
+    assert not strutils.is_mostly_bin("")
 
 def test_is_xml():
     assert not strutils.is_xml(b"foo")