PEP8Bear: Add infinite line length

Allows infinite line length when
max_line_length is set to 0.

Closes coala#2436

bears/python/PEP8Bear.py

@@ -1,4 +1,5 @@
 import autopep8
+import sys
 
 from coalib.bearlib import deprecate_settings
 from coalib.bearlib.spacing.SpacingHelper import SpacingHelper
@@ -31,13 +32,17 @@ def run(self, filename, file,
         functionality of the code in any way.
 
         :param max_line_length:   Maximum number of characters for a line.
+                                  When set to 0 allows infinite line length.
         :param indent_size:       Number of spaces per indentation level.
         :param pep_ignore:        A list of errors/warnings to ignore.
         :param pep_select:        A list of errors/warnings to exclusively
                                   apply.
         :param local_pep8_config: Set to true if autopep8 should use a config
                                   file as if run normally from this directory.
         """
+        if not max_line_length:
+            max_line_length = sys.maxsize
+
         options = {'ignore': pep_ignore,
                    'select': pep_select,
                    'max_line_length': max_line_length,

tests/python/PEP8BearTest.py

@@ -23,6 +23,11 @@ def test_line_length(self):
         self.check_invalidity(self.uut,
                               ['a = 1 + 1 + 1 + 1 + 1 + 1 + 1'])
 
+    def test_infinite_line_length(self):
+        valid_file = ['a =' + ' 1 +' * 100 + ' 1']
+        self.section.append(Setting('max_line_length', '0'))
+        self.check_validity(self.uut, valid_file)
+
     def test_indent_level(self):
         test_code = ['def func():\n',
                      '    pass\n']