warn if object to convert is not a number, test it

tests/test_files.py

@@ -64,5 +64,11 @@ def test_nonexistent_path(tmpdir):
 @pytest.mark.parametrize("size_num", list(range(0, 10)) + [i/3 for i in range(0, 10)])
 def test_filesize_to_str_int(size_num):
     """ Works with int and returns str """
-    print(size_num)
     assert isinstance(filesize_to_str(size_num), str)
+
+
+@pytest.mark.parametrize("obj", ["test", [], tuple()])
+def test_filesize_to_str_other(obj):
+    """ Returns the original object if it's not an int or float and warns """
+    with pytest.warns(UserWarning):
+        assert filesize_to_str(obj) == obj

ubiquerg/files.py

@@ -2,6 +2,7 @@
 
 from hashlib import md5
 import os
+from warnings import warn
 
 __all__ = ["checksum", "size", "filesize_to_str"]
 FILE_SIZE_UNITS = ['B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB']
@@ -66,4 +67,5 @@ def filesize_to_str(size):
             if size < 1024:
                 return "{}{}".format(round(size, 1), unit)
             size /= 1024
+    warn("size argument was neither an int nor a float, returning the original object")
     return size