Workaround tox 2.3.0 regression.

[tseaver]

See:
https://bitbucket.org/hpk42/tox/issues/294/tox-23-regression.

[tseaver]

@dhermes @jgeewax This one is pretty urgent: all our tests break with tox 2.3.0. I intend to merge as soon as Travis is green.

[dhermes]

I have a better fix.

[dhermes]

ISTM the issue is the use of {[testenv]setenv}. This is very similar to the issue you linked to.

[dhermes]

diff --git a/tox.ini b/tox.ini
index e92ace7..0b3b727 100644
--- a/tox.ini
+++ b/tox.ini
@@ -54,7 +54,7 @@ passenv = {[testenv:system-tests]passenv} SPHINX_RELEASE READTHEDOCS LOCAL_RTD

 [testenv:docs-rtd]
 setenv =
-    {[testenv]setenv}
+    PYTHONPATH = {toxinidir}/_testing
     LOCAL_RTD = True
 basepython = {[testenv:docs]basepython}
 commands =

[dhermes]

Just ran tox -e py27 with this change and it passed with no issues.

[dhermes]

Ditto on py26,py33,py34,cover and lint.

[tseaver]

@dhermes I'm not sure what you mean: do you want to push a different PR? Or do you think I should update this one?

[dhermes]

Just update this one and feel free to merge if you can get Travis to pass