Re-allow for relative paths for exclude

Previously, all testing was done from the directory in which the
configuration file lived, so this bug went unnoticed. However, if you
run Flake8 against its own source from a directory above, you would
notice that the patterns in the exclude config value in tox.ini were
ignored. This is because we (like any reasonable person) are using
relative paths. The path is relative, however, to the directory in
which the configuration file was located. So we keep track of which
directory that is and use that to normalize the paths in the config
file.

Yes, there is an unrelated change to our tox.ini in this commit as
well. ;-)

Closes #194

2 files changed, 10 insertions, 5 deletions

diff --git a/src/flake8/options/config.py b/src/flake8/options/config.py
index d1408fe..8306251 100644
--- a/src/flake8/options/config.py
+++ b/src/flake8/options/config.py
@@ -43,6 +43,8 @@ class ConfigFileFinder(object):
         # List of filenames to find in the local/project directory
         self.project_filenames = ('setup.cfg', 'tox.ini', self.program_config)
 
+        self.local_directory = os.path.abspath(os.curdir)
+
         if not args:
             args = ['.']
         self.parent = self.tail = os.path.abspath(os.path.commonprefix(args))
@@ -78,6 +80,7 @@ class ConfigFileFinder(object):
                 if os.path.exists(filename):
                     yield filename
                     found_config_files = True
+                    self.local_directory = parent
             (parent, tail) = os.path.split(parent)
 
     def local_config_files(self):
@@ -160,9 +163,11 @@ class MergedConfigParser(object):
         self.config_finder = ConfigFileFinder(self.program_name, self.args,
                                               self.extra_config_files)
 
-    @staticmethod
-    def _normalize_value(option, value):
-        final_value = option.normalize(value)
+    def _normalize_value(self, option, value):
+        final_value = option.normalize(
+            value,
+            self.config_finder.local_directory,
+        )
         LOG.debug('%r has been normalized to %r for option "%s"',
                   value, final_value, option.config_name)
         return final_value
diff --git a/src/flake8/options/manager.py b/src/flake8/options/manager.py
index 58d8b2d..de9356e 100644
--- a/src/flake8/options/manager.py
+++ b/src/flake8/options/manager.py
@@ -121,14 +121,14 @@ class Option(object):
             return self.long_option_name[2:].replace('-', '_')
         return self.short_option_name[1]
 
-    def normalize(self, value):
+    def normalize(self, value, *normalize_args):
         """Normalize the value based on the option configuration."""
         if self.normalize_paths:
             # Decide whether to parse a list of paths or a single path
             normalize = utils.normalize_path
             if self.comma_separated_list:
                 normalize = utils.normalize_paths
-            return normalize(value)
+            return normalize(value, *normalize_args)
         elif self.comma_separated_list:
             return utils.parse_comma_separated_list(value)
         return value