Added a test for clean_filename.

tests/test_misc.py

@@ -0,0 +1,20 b''
+import re
+import nose.tools as nt
+from converters.base import clean_filename
+
+
+def test_clean_filename():
+    good_chars = re.compile('^[a-zA-Z0-9_]+$')
+
+    def check_str(s):
+        nt.assert_true(good_chars.match(clean_filename(s)) is not None)
+
+    strings = [
+        'abCaBdX0753--$++()',
+        '()$(@dasdk_%^^&&($#*@',
+        '%(#)@#@%^(^#DKDOPSfks0943k',
+        '439DDxsx___dsaigfj6&^',
+        '\'sdf594,,<<.>>/"""\'\'{}||]]'
+    ]
+    for s in strings:
+        yield check_str, s