test: is pytest-xdist necessary?

.travis.yml

@@ -8,7 +8,7 @@ python:
   - "3.7"
   - "nightly"
   - "pypy3.5"
-install: pip install -U $DEPS pytest pytest-asyncio pytest-xdist flaky structlog
+install: pip install -U $DEPS pytest pytest-asyncio flaky structlog
 script: pytest
 env:
   global:

setup.py

@@ -28,7 +28,6 @@ setup(
   tests_require = [
     'pytest',
     'pytest-asyncio',
-    'pytest-xdist',
     'flaky',
   ],
   entry_points = {