test with pytest42

Author: blueyed

.travis.yml

@@ -30,6 +30,10 @@ jobs:
     - python: 3.8
       env: TOXENV=py38-dj30-sqlite-xdist-coverage
 
+    # Explicitly test oldest supported pytest.
+    - python: 3.7
+      env: TOXENV=py37-dj21-sqlite-pytest42-coverage
+
     - python: 3.6
       env: TOXENV=py36-djmaster-sqlite-coverage
 

tox.ini

@@ -27,6 +27,9 @@ deps =
     postgres: psycopg2-binary
     coverage: coverage-enable-subprocess
 
+    # Oldest supported pytest.
+    pytest42: pytest>=4.1,<4.2
+    pytest42: attrs==17.4.0
     xdist: pytest-xdist>=1.15
 
 setenv =