tox: refactor configuration

* Bump the minimum version to a more modern 3.0.0.
* Simplify configuration keeping the same envdir structure.

Change-Id: I4e948fafb18b230e0c9404f415c76a958bc67fd7

tox.ini

@@ -1,14 +1,10 @@
 [tox]
-minversion = 1.6
+minversion = 3.0.0
 envlist = py{35,36,37}-{flake8,unit,unit-min,unitbase,bandit,prospector,sphinx}
 skip_missing_interpreters = True
 
 [testenv]
 usedevelop = True
-basepython =
-    py37: python3.7
-    py36: python3.6
-    py35: python3.5
 whitelist_externals = sed
 description =
     flake8: Style consistency checker
@@ -19,10 +15,19 @@ description =
     sphinx: Build documentation and manpages
     integration: Run integration tests
     min: [minimum supported version of dependencies]
-    py37: (Python 3.7)
-    py36: (Python 3.6)
     py35: (Python 3.5)
-envdir = {toxworkdir}/py36-tests
+    py36: (Python 3.6)
+    py37: (Python 3.7)
+envdir =
+    py35-unitbase: {toxworkdir}/py35-tests-base
+    py36-unitbase: {toxworkdir}/py36-tests-base
+    py37-unitbase: {toxworkdir}/py37-tests-base
+    py35-min: {toxworkdir}/py35-tests-min
+    py36-min: {toxworkdir}/py36-tests-min
+    py37-min: {toxworkdir}/py37-tests-min
+    py35-!unitbase-!min: {toxworkdir}/py35-tests
+    py36-!unitbase-!min: {toxworkdir}/py36-tests
+    py37-!unitbase-!min: {toxworkdir}/py37-tests
 commands =
     flake8: flake8 setup.py cumin doc
     unit: py.test -p no:logging --strict --cov-report=term-missing --cov=cumin cumin/tests/unit {posargs}
@@ -37,84 +42,22 @@ commands =
     sphinx: sed -i='' -e 's/^\.B/.B /' '{toxinidir}/doc/build/man/cumin.1'
     integration: "{toxinidir}/cumin/tests/integration/docker.sh" "transports/clustershell"
 deps =
-    # Use install_requires and the additional extras_require[tests] from setup.py, force the minimum version for
-    # environments where 'min' is one of the dash-separated token.
+    # Use install_requires and the additional extras_require[NAME] from setup.py
+    unitbase: .[tests-base]
     min: .[tests-min]
-    .[tests]
+    !min-!unitbase: .[tests]
 setenv =
     min: CUMIN_MIN_DEPS=1
     integration: USER=root
     integration: SUDO_USER=integration-tests
 
-# All the below are needed until https://github.com/tox-dev/tox/issues/659 is resolved
-[testenv:py37-flake8]
-envdir = {toxworkdir}/py37-tests
-
-[testenv:py37-unit]
-envdir = {toxworkdir}/py37-tests
-
-[testenv:py37-unit-min]
-envdir = {toxworkdir}/py37-tests-min
-
-[testenv:py37-unitbase]
-envdir = {toxworkdir}/py37-tests-base
-deps = .[tests-base]
-
-[testenv:py37-bandit]
-envdir = {toxworkdir}/py37-tests
-
-[testenv:py37-prospector]
-envdir = {toxworkdir}/py37-tests
-
-[testenv:py37-sphinx]
-envdir = {toxworkdir}/py37-tests
-
-[testenv:py37-integration]
-envdir = {toxworkdir}/py37-tests
-
-[testenv:py37-integration-min]
-envdir = {toxworkdir}/py37-tests-min
-
-[testenv:py36-unit-min]
-envdir = {toxworkdir}/py36-tests-min
-
-[testenv:py36-unitbase]
-envdir = {toxworkdir}/py36-tests-base
-deps = .[tests-base]
-
 # Needed it until https://github.com/tox-dev/tox/issues/505 is resolved
-[testenv:py36-integration]
-
-[testenv:py36-integration-min]
-envdir = {toxworkdir}/py36-tests-min
-
-[testenv:py35-flake8]
-envdir = {toxworkdir}/py35-tests
-
-[testenv:py35-unit]
-envdir = {toxworkdir}/py35-tests
-
-[testenv:py35-unit-min]
-envdir = {toxworkdir}/py35-tests-min
-
-[testenv:py35-unitbase]
-envdir = {toxworkdir}/py35-tests-base
-deps = .[tests-base]
-
-[testenv:py35-bandit]
-envdir = {toxworkdir}/py35-tests
-
-[testenv:py35-prospector]
-envdir = {toxworkdir}/py35-tests
-
-[testenv:py35-sphinx]
-envdir = {toxworkdir}/py35-tests
-
 [testenv:py35-integration]
-envdir = {toxworkdir}/py35-tests
-
+[testenv:py36-integration]
+[testenv:py37-integration]
 [testenv:py35-integration-min]
-envdir = {toxworkdir}/py35-tests-min
+[testenv:py36-integration-min]
+[testenv:py37-integration-min]
 
 [flake8]
 max-line-length = 120