diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index cdbc48a..9a9f8f2 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -11,14 +11,15 @@ build:image:
     - docker login -u gitlab-ci-token -p $CI_BUILD_TOKEN registry.gitlab.com
     - docker build -t registry.gitlab.com/danielsiepmann/neotags .
     - docker push registry.gitlab.com/danielsiepmann/neotags:latest
-  # only:
-  #   - master
+  only:
+    changes:
+      - Dockerfile
 
 lint:coding-guideline:
   image: 'registry.gitlab.com/danielsiepmann/neotags:latest'
   stage: test
   script:
-    - pep8 .
+    - pycodestyle --show-source --show-pep8 .
 
 test:
   image: 'registry.gitlab.com/danielsiepmann/neotags:latest'
diff --git a/Dockerfile b/Dockerfile
index cd7049c..b673e0e 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -5,4 +5,4 @@ LABEL Description="This image should provide environment to lint neotags" Vendor
 
 # Install dependencies
 RUN pip install --upgrade pip
-RUN pip install --no-cache-dir pep8 pynvim pyfakefs==3.1
+RUN pip install --no-cache-dir pycodestyle==2.5.0 pynvim pyfakefs==3.1
diff --git a/readme.rst b/readme.rst
index 1afbfbc..e9def63 100644
--- a/readme.rst
+++ b/readme.rst
@@ -48,4 +48,4 @@ Install dependencies:
 
 Run tests:
 
-``cd rplugin && python -m unittest test.test_neotags``
+``docker run -it --rm -v $PWD/rplugin:/project -w /project registry.gitlab.com/danielsiepmann/neotags:latest python -m unittest test.test_neotags``
diff --git a/rplugin/python3/neotags.py b/rplugin/python3/neotags.py
index a04a57e..3e174c9 100644
--- a/rplugin/python3/neotags.py
+++ b/rplugin/python3/neotags.py
@@ -24,7 +24,7 @@ class NeotagsPlugin(object):
         for option, default in self.options.items():
             try:
                 variable = 'neotags_%s' % option
-                self.options[option] = self.nvim.vars[variable]
+                self.options[option] = self.nvim.eval('g:%s' % variable)
             except pynvim.api.nvim.NvimError:
                 self.options[option] = default
 
@@ -36,11 +36,11 @@ class NeotagsPlugin(object):
         self.debug('Triggered for "%s"' % filename)
 
         pwd = self.nvim.funcs.execute('pwd').strip()
-        relative_filename = filename.replace(pwd, '').lstrip('\/')
+        relative_filename = filename.replace(pwd, '').lstrip(r'\/')
 
         try:
             tags_file = self.get_tags_file(filename)
-        except:
+        except BaseException:
             self.error(
                 'Could not determine tags file to update for "%s"' % (
                     filename
@@ -53,7 +53,7 @@ class NeotagsPlugin(object):
             self.strip_existing_tags(tags_file, relative_filename)
             self.generate_tags(tags_file, relative_filename)
             self.debug('Tags updated for "%s"' % filename)
-        except:
+        except BaseException:
             self.error(
                 'Failed to update tags for "%s", reason: %s' % (
                     filename, traceback.format_exc()
diff --git a/rplugin/test/test_neotags.py b/rplugin/test/test_neotags.py
index af2766d..ba52754 100644
--- a/rplugin/test/test_neotags.py
+++ b/rplugin/test/test_neotags.py
@@ -1,3 +1,4 @@
+import unittest
 from unittest.mock import Mock
 from unittest.mock import MagicMock
 from pyfakefs import fake_filesystem_unittest
@@ -18,22 +19,42 @@ class TestNeotagsPlugin(fake_filesystem_unittest.TestCase):
         self.plugin = NeotagsPlugin(Mock(pynvim.api.nvim))
 
     def test_default_options(self):
-        self.assertEqual('ctags', self.plugin.options['ctags_cmd'])
         self.assertEqual('tags', self.plugin.options['tags_filename'])
+        self.assertEqual('ctags', self.plugin.options['ctags_cmd'])
         self.assertEqual(False, self.plugin.options['logging'])
 
     def test_custom_options(self):
-        self.plugin.nvim.configure_mock(vars={})
-        self.plugin.nvim.vars['neotags_tags_filename'] = 'new_tags'
-        self.plugin.nvim.vars['neotags_ctags_cmd'] = 'new_ctags'
-        self.plugin.nvim.vars['neotags_logging'] = True
+        def eval(argument):
+            if argument == 'g:neotags_tags_filename':
+                return 'new_tags'
+            if argument == 'g:neotags_ctags_cmd':
+                return 'new_ctags'
+            if argument == 'g:neotags_logging':
+                return True
 
+        self.plugin.nvim.configure_mock(eval=eval)
         self.plugin.update_settings()
 
         self.assertEqual('new_tags', self.plugin.options['tags_filename'])
         self.assertEqual('new_ctags', self.plugin.options['ctags_cmd'])
         self.assertEqual(True, self.plugin.options['logging'])
 
+    def test_fallback_option(self):
+        def eval(argument):
+            if argument == 'g:neotags_tags_filename':
+                return 'new_tags'
+            if argument == 'g:neotags_ctags_cmd':
+                raise pynvim.api.nvim.NvimError('')
+            if argument == 'g:neotags_logging':
+                return True
+
+        self.plugin.nvim.configure_mock(eval=eval)
+        self.plugin.update_settings()
+
+        self.assertEqual('new_tags', self.plugin.options['tags_filename'])
+        self.assertEqual('ctags', self.plugin.options['ctags_cmd'])
+        self.assertEqual(True, self.plugin.options['logging'])
+
     def test_debug_logs_to_nvim_when_logging_is_active(self):
         self.plugin.options['logging'] = True
         self.plugin.nvim.out_write = MagicMock()
@@ -128,3 +149,7 @@ class TestNeotagsPlugin(fake_filesystem_unittest.TestCase):
         self.plugin.strip_existing_tags(tags_file, os.path.basename(filename))
         with open(tags_file) as f, open(expected_tags_file) as e:
             self.assertEqual(e.read(), f.read())
+
+
+if __name__ == '__main__':
+    unittest.main()