Python 2.6 broke. I am taking this as a chance to drop support for it

and python3.3 but will be supported pypy3 and python3.6

.travis.yml

@@ -1,14 +1,18 @@
 language: python
 matrix:
   include:
+    - python: 2.7
+      env: TOXENV=py27
+    - python: 3.4
+      env: TOXENV=py34
     - python: 3.5
       env: TOXENV=py35
-env:
-  - TOXENV=py26
-  - TOXENV=py27
-  - TOXENV=py33
-  - TOXENV=py34
-  - TOXENV=pypy
+    - python: 3.6
+      env: TOXENV=py36
+    - python: pypy
+      env: TOXENV=pypy
+    - python: pypy3
+      env: TOXENV=pypy3
 install:
   - travis_retry pip install coveralls tox
 script:

README.rst

@@ -263,7 +263,7 @@ For example, setting up python 3:
 
     pyvenv venv
     source venv/bin/activate
-    pip install -r test-requirements-py27-py3.txt
+    pip install -r test-requirements.txt
 
 
 Special Thanks

diff_cover/tests/helpers.py

@@ -2,19 +2,13 @@
 Test helper functions.
 """
 import random
-import sys
 
 import io
 import six
 import os.path
 import difflib
 from nose.tools import ok_
 
-if sys.version_info[:2] <= (2, 6):
-    import unittest2 as unittest
-else:
-    import unittest
-
 HUNK_BUFFER = 2
 MAX_LINE_LENGTH = 300
 LINE_STRINGS = ['test', '+ has a plus sign', '- has a minus sign']

diff_cover/tests/test_args.py

@@ -1,9 +1,9 @@
 from __future__ import unicode_literals
 import contextlib
 import sys
-from mock import Mock, patch
+from mock import patch
 from diff_cover.tool import parse_coverage_args, parse_quality_args, main
-from diff_cover.tests.helpers import unittest
+import unittest
 
 
 @contextlib.contextmanager

diff_cover/tests/test_diff_reporter.py

@@ -1,10 +1,11 @@
 # -*- coding: utf-8 -*-
 from __future__ import unicode_literals
 import mock
+import unittest
 from textwrap import dedent
 from diff_cover.diff_reporter import GitDiffReporter
 from diff_cover.git_diff import GitDiffTool, GitDiffError
-from diff_cover.tests.helpers import line_numbers, git_diff_output, unittest
+from diff_cover.tests.helpers import line_numbers, git_diff_output
 
 
 class GitDiffReporterTest(unittest.TestCase):

diff_cover/tests/test_git_diff.py

@@ -2,8 +2,8 @@
 import mock
 
 from diff_cover.command_runner import CommandError
-from diff_cover.git_diff import GitDiffTool, GitDiffError
-from diff_cover.tests.helpers import unittest
+from diff_cover.git_diff import GitDiffTool
+import unittest
 
 
 class TestGitDiffTool(unittest.TestCase):

diff_cover/tests/test_git_path.py

@@ -1,7 +1,7 @@
 from __future__ import unicode_literals
 import mock
 from diff_cover.git_path import GitPathTool
-from diff_cover.tests.helpers import unittest
+import unittest
 
 
 class TestGitPathTool(unittest.TestCase):

diff_cover/tests/test_integration.py

@@ -11,7 +11,7 @@
 from collections import defaultdict
 from io import BytesIO
 from subprocess import Popen
-from diff_cover.tests.helpers import unittest
+import unittest
 import io
 import six
 

diff_cover/tests/test_report_generator.py

@@ -11,8 +11,9 @@
     StringReportGenerator, TemplateReportGenerator
 )
 from diff_cover.tests.helpers import (
-    load_fixture, assert_long_str_equal, unittest
+    load_fixture, assert_long_str_equal
 )
+import unittest
 from diff_cover.violationsreporters.violations_reporter import BaseViolationReporter, Violation
 
 

diff_cover/tests/test_snippets.py

@@ -7,8 +7,9 @@
 from pygments.token import Token
 from diff_cover.snippets import Snippet
 from diff_cover.tests.helpers import load_fixture,\
-    fixture_path, assert_long_str_equal, unittest
+    fixture_path, assert_long_str_equal
 import six
+import unittest
 
 
 class SnippetTest(unittest.TestCase):

diff_cover/tests/test_violations_reporter.py

@@ -12,7 +12,7 @@
 from diff_cover.violationsreporters import base
 
 from diff_cover.command_runner import CommandError, run_command_for_code
-from diff_cover.tests.helpers import unittest
+import unittest
 from diff_cover.violationsreporters.base import QualityReporter
 from diff_cover.violationsreporters.violations_reporter import (
     XmlCoverageReporter, Violation, pycodestyle_driver, pyflakes_driver,

requirements/test-requirements.txt

@@ -5,4 +5,6 @@ coverage
 pycodestyle
 flake8
 pyflakes
+pylint
+pydocstyle
 -r requirements.txt

tox.ini

@@ -1,11 +1,11 @@
 [tox]
-envlist = py26, py27, py33, py34, py35, pypy
+envlist = py27, py34, py35, py36, pypy, pypy3
 
 [testenv]
 whitelist_externals =
     /usr/bin/git
 deps =
-    -r{toxinidir}/requirements/test-requirements-py27-py3.txt
+    -r{toxinidir}/requirements/test-requirements.txt
 commands =
     coverage run -m nose {posargs}
     coverage xml
@@ -15,12 +15,6 @@ commands =
     diff-quality --violation=pyflakes
     diff-quality --violation=pylint
 
-[testenv:py26]
-deps =
-    -r{toxinidir}/requirements/test-requirements-py26.txt
-    argparse
-    unittest2
-
 [testenv:py27]
 commands =
     {[testenv]commands}