cope with xdist breakage

Author: mr-c

appveyor.yml

@@ -32,7 +32,7 @@ install:
   - ps: 'Install-Product node 0.12 x64'
   - "set PATH=%PYTHON%\\Scripts;%PATH%"
   - "%PYTHON%\\python.exe -m pip install -U pip setuptools^>=20.3 wheel"
-  - "%PYTHON%\\python.exe -m pip install -U codecov -rtest-requirements.txt pytest-xdist "
+  - "%PYTHON%\\python.exe -m pip install -U codecov -rtest-requirements.txt pytest-xdist<1.28 "
     # Note the use of a `^` to escape the `>`
 
 build_script:

tox.ini

@@ -27,7 +27,7 @@ passenv =
 deps =
   -rrequirements.txt
   py{27,34,35,36,37}-unit: codecov
-  py{27,34,35,36,37}-unit: pytest-xdist
+  py{27,34,35,36,37}-unit: pytest-xdist<1.28.0
   py{27,34,35,36,37}-unit: pytest-cov
   py{27,34,35,36,37}-unit: -rtest-requirements.txt
   py{27,34,35,36,37}-unit: galaxy-lib