diff --git a/.travis.yml b/.travis.yml
index 7849fb0..e6ff486 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,6 +16,7 @@ matrix:
 before_install:
 - if [[ $TRAVIS_PYTHON_VERSION == '3.2' ]]; then pip install 'coverage<4.0.0'; fi
 - pip install codecov
+- pip install 'py>=1.5.0'
 install:
 - pip install -e .
 - pip install -r requirements_dev.txt
diff --git a/requirements_dev.txt b/requirements_dev.txt
index 697427b..7d4afaa 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -1,6 +1,5 @@
 mock==2.0.0
 pytest==3.5.0
-pytest-pep8
-pytest-flakes
+pytest-flake8
 pytest-cov==2.5.1
 flask
\ No newline at end of file
diff --git a/setup.py b/setup.py
index 42ea7dc..ba10e04 100644
--- a/setup.py
+++ b/setup.py
@@ -38,8 +38,7 @@ class PyTest(TestCommand):
         TestCommand.finalize_options(self)
         self.test_args = [
             '-sv',
-            '--pep8',
-            '--flakes',
+            '--flake8',
             '--junitxml', 'reports/junit.xml',
             '--cov', 'openapi_core',
             '--cov-report', 'term-missing',
diff --git a/tests/integration/test_validators.py b/tests/integration/test_validators.py
index bd92552..55a1199 100644
--- a/tests/integration/test_validators.py
+++ b/tests/integration/test_validators.py
@@ -283,7 +283,7 @@ class TestResponseValidator(object):
 
     def test_invalid_media_type_value(self, validator):
         request = MockRequest(self.host_url, 'get', '/v1/pets')
-        response = MockResponse('\{\}')
+        response = MockResponse("{}")
 
         result = validator.validate(request, response)