Test py37, update classifiers and test with more modern pytest versions

Author: nicoddemus

.travis.yml

@@ -16,6 +16,9 @@ after_success:
 
 jobs:
   include:
+    - python: '3.7'
+      sudo: required
+      dist: xenial
     - python: '3.6'
       env: TOXENV=linting
     - python: '3.6'

setup.py

@@ -35,6 +35,7 @@
         'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
         'Topic :: Software Development :: Testing',
     ]
 )

tox.ini

@@ -1,12 +1,12 @@
 [tox]
-envlist = py{27,34,35,36}-pytest{34,35},linting,norewrite
+envlist = py{27,34,35,36,37}-pytest{37,38},linting,norewrite
 
 [testenv]
 passenv = USER USERNAME
 deps =
     coverage
-    pytest34: pytest~=3.4
-    pytest35: pytest~=3.5
+    pytest37: pytest~=3.7
+    pytest38: pytest~=3.8
 commands =
     coverage run --append --source=pytest_mock.py -m pytest test_pytest_mock.py