bsipocz · Mar 13, 2020 · Dec 13, 2019
diff --git a/.travis.yml b/.travis.yml
@@ -13,6 +13,7 @@ env:
         - SETUP_CMD='test'
         - TEST_CMD='py.test test_env.py'
         - PYTHON_VERSION=3.6
+        - SETUP_CONDA=true
 
     matrix:
         - SETUP_CMD='egg_info' TEST_CMD='python --version'
@@ -254,6 +255,11 @@ matrix:
           env: SETUP_CMD='test' CONDA_ENVIRONMENT='conda_environment.yml' CONDA_DEPENDENCIES="scipy"
                TEST_CMD="python -c $'import matplotlib\nimport scipy'"
 
+        - os: linux
+          python: 3.7
+          language: python
+          env: SETUP_CONDA=false TOXENV="test" TEST_CMD="source ci-helpers/tox/run_tox.sh && test -f tox_worked.log"
+
     allow_failures:
         # JOB .34
         - os: linux
@@ -266,9 +272,10 @@ before_install:
       else
         ln -s . ci-helpers;
       fi
-    - source ci-helpers/travis/setup_conda.sh
+    - if [[ $SETUP_CONDA == true ]]; then source ci-helpers/travis/setup_conda.sh; fi
 
 script:
+   - python --version
    - eval $TEST_CMD
 
 after_success:

diff --git a/README.md b/README.md
@@ -280,6 +280,29 @@ environment variables:
 * ``RETRY_DELAY``: a positive integer specifying the number of seconds to wait
   before retrying. If not set, this will default to ``$RETRY_DELAY=2``.
 
+### Tox
+
+For CI builds using tox, we also provide a script that installs and runs tox, assuming that the following environment
+variables are defined:
+
+* ``TOXENV``: the name of the tox environment to run
+* ``TOXARGS``: the arguments to pass to tox
+* ``TOXPOSARGS``: the positional arguments to pass after the ``--`` separator
+
+The resulting tox command looks like::
+
+    tox -e $TOXENV $TOXPOSARGS -- $TOXPOSARGS
+
+This script may also apply patches, for example to prevent a too recent version
+of pytest from being installed if this breaks many packages, or excluding a
+broken version of another package. This is done by running a proxy PyPI server
+which excludes the problematic package versions. In general however, the goal
+will be to not have any patches most of the time and to only use this in extreme
+circumstances.
+
+Note that this script will not set up conda and will by default just use the
+active Python interpreter. Aside from the three environment variables mentioned
+in this section, no other environment variables are taken into account.
 
 ### Utils
 

diff --git a/tox.ini b/tox.ini
@@ -0,0 +1,9 @@
+[tox]
+envlist = test
+
+[testenv]
+skip_install = true
+whitelist_externals =
+    touch
+commands =
+    touch tox_worked.log
diff --git a/tox/run_tox.sh b/tox/run_tox.sh
@@ -0,0 +1,53 @@
+#!/bin/bash -xe
+
+# This script installs and runs tox, assuming that the following environment
+# variables are defined:
+#
+# * TOXENV: the name of the tox environment to run
+# * TOXARGS: the arguments to pass to tox
+# * TOXPOSARGS: the positional arguments to pass after the -- separator
+#
+# The resulting tox command looks like:
+#
+#     tox -e $TOXENV $TOXPOSARGS -- $TOXPOSARGS
+#
+# This script may also apply patches, for example to prevent a too recent
+# version of pytest from being installed, or excluding a broken version of
+# another package. This is done by running a proxy PyPI server which
+# excludes the problematic package versions.
+
+echo '########################################################################'
+echo ''
+echo 'ci-helpers run_tox.sh script'
+echo ''
+echo 'TOXENV='$TOXENV
+echo 'TOXARGS='$TOXARGS
+echo 'TOXPOSARGS='$TOXPOSARGS
+echo ''
+echo 'No global patches being applied'
+echo ''
+echo 'Installing tox:'
+echo ''
+
+# Start off by installing tox
+pip install tox
+
+# If PyPI patches are needed, uncommend the following line
+# pip install tox-pypi-filter
+
+echo ''
+echo 'Listing Python packages:'
+echo ''
+
+# List the current installed packages
+pip freeze
+
+echo ''
+echo 'Running tox:'
+echo ''
+
+# Run tox. If PyPI patches are needed, add a --pypi-filter=...
+# option to the command, e.g. --pypi-filter='pytest<5'
+tox -e $TOXENV $TOXARGS -- $TOXPOSARGS
+echo ''
+echo '########################################################################'