tox: Rename extra to custom

tox.ini

@@ -3,7 +3,7 @@
 envlist =
     black, pylint, flake8,
     py{26,27,36,37,38},
-    extra
+    custom
 skipsdist = true
 skip_missing_interpreters = true
 
@@ -17,6 +17,7 @@ deps =
     py26: pytest
 
 [base]
+system_python = /usr/bin/python3
 passenv = *
 setenv =
     PYTHONPATH = {toxinidir}/library:{toxinidir}/module_utils
@@ -24,6 +25,8 @@ setenv =
 changedir = {toxinidir}/tests
 covtarget = {toxinidir}/library --cov {toxinidir}/module_utils
 pytesttarget = .
+whitelist_externals =
+    bash
 
 [testenv:py26]
 envdir = {toxworkdir}/env-{env:TRAVIS_PYTHON_VERSION:2.6}
@@ -197,39 +200,15 @@ commands =
     {[testenv:molecule_syntax]commands}
     {[testenv:molecule_test]commands}
 
-# Here we provide a way how a role can add its custom command to be run. Such
-# extra command is run at the end of each testenv run and is driven by
-# environment variables. Involved environment variables are:
-#
-#   LSR_TEXTRA_DEPS
-#     - contains dependency needed by commands to run smoothly; if more than
-#       one dependency is needed, use external file together with '-r' option
-#       (see PEP 508)
-#
-#   LSR_TEXTRA_DIR
-#     - directory to which to cd
-#
-#   LSR_TEXTRA_CMD
-#     - custom command to be run
-#
-# Example: `network` system role need to run `./tests/ensure_non_running_provider.py`
-#          to check for the existence of `*_provider.yml` playbooks. The script
-#          is run in Python 3.6.
-#
-#          To make this possible, we add to `.travis/config.sh` a snippet:
-#
-#              export LSR_TEXTRA_DEPS='PyYAML'
-#              export LSR_TEXTRA_DIR='tests'
-#              export LSR_TEXTRA_CMD='./ensure_non_running_provider.py'
-#
-[testenv:extra]
-envdir = {toxworkdir}/env-{env:TRAVIS_PYTHON_VERSION:extra}
+[testenv:custom]
+envdir = {toxworkdir}/env-{env:TRAVIS_PYTHON_VERSION:custom}
 deps =
-    {env:LSR_TEXTRA_DEPS:}
+    -rcustom_requirements.txt
 passenv = *
-changedir = {toxinidir}/{env:LSR_TEXTRA_DIR:.}
+whitelist_externals =
+    {[base]whitelist_externals}
 commands =
-    {env:LSR_TEXTRA_CMD:python --version}
+    bash {toxinidir}/.travis/custom.sh {envpython} {[base]system_python}
 
 [pytest]
 addopts = -rxs
@@ -248,9 +227,9 @@ max-line-length = 88
 
 [travis]
 python =
-  2.6: py26,extra
-  2.7: py27,flake8,pylint,extra
-  3.5: coveralls,molecule,extra
-  3.6: py36,black,extra
-  3.7: py37,extra
-  3.8: py38,extra
+  2.6: py26,custom
+  2.7: py27,flake8,pylint,custom
+  3.5: coveralls,molecule,custom
+  3.6: py36,black,custom
+  3.7: py37,custom
+  3.8: py38,custom