Add python3.7 unit test job in tox.ini

Add a unit test job running under Python 3.7.

Change-Id: I741c27cf83ca41e27c5c59f2e7ce57bf8a21f1e2

setup.cfg

@@ -16,6 +16,7 @@ classifier =
     Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.6
+    Programming Language :: Python :: 3.7
     Development Status :: 5 - Production/Stable
     Natural Language :: English
     Intended Audience :: Developers

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 2.0
-envlist = py27,py36,pep8,pylint
+envlist = py27,py36,py37,pep8,pylint
 skipsdist = True
 
 [testenv]
@@ -45,6 +45,17 @@ commands =
     rm -f .coverage
     rm -rf .testrepository
 
+[testenv:py37]
+basepython = python3.7
+setenv = OS_PATH_TEST = ./freezer_api/tests/unit
+commands =
+    find . -type f -name "*.py[c|o]" -delete
+    rm -rf .testrepository
+    python setup.py test --coverage --coverage-package-name freezer_api --testr-args={posargs}
+    coverage report -m
+    rm -f .coverage
+    rm -rf .testrepository
+
 [testenv:venv]
 basepython = python3
 commands = {posargs}