Update tox.ini and .gitlab-ci.yml to test Python 3 code updates

.gitlab-ci.yml

@@ -20,17 +20,26 @@ stages:
 before_script:
 - pip install -e .[dev]
 
+python3.6:
+  image: python:3.6
+  tags:
+  - passoft
+  stage: test
+  script:
+  - python -m unittest
 
-python2:
-  image: python:2.7
+python3.7:
+  image: python:3.7
   tags:
   - passoft
   stage: test
-  script: tox -e py27
+  script:
+  - python -m unittest
 
-python3:
-  image: python:3.6
+python3.8:
+  image: python:3.8
   tags:
   - passoft
   stage: test
-  script: tox -e py36
+  script:
+  - python -m unittest

tox.ini

 [tox]
-envlist = py27, py36 flake8
-
-[travis]
-python =
-    2.7: py27
-    3.6: py36
-
-[testenv:flake8]
-basepython = python
-deps = flake8
-commands = flake8 ckmseed
+envlist = py36, py37, py38
 
 [testenv]
-setenv =
-    PYTHONPATH = {toxinidir}
-commands=python setup.py test
-
-
+commands = python -m unittest