White list external "env" used by Travis for coverage

Author: nicoddemus

tox.ini

@@ -17,6 +17,7 @@ envlist =
     docs
 
 [testenv]
+whitelist_externals = env
 commands =
     {env:_PYTEST_TOX_COVERAGE_RUN:} pytest --lsof -ra {posargs:testing}
 passenv = USER USERNAME
@@ -56,6 +57,7 @@ deps =
     nose
     hypothesis>=3.56
     {env:_PYTEST_TOX_EXTRA_DEP:}
+whitelist_externals = env
 commands =
     {env:_PYTEST_TOX_COVERAGE_RUN:} pytest -n8 -ra {posargs:testing}
 
@@ -69,6 +71,7 @@ platform = linux|darwin
 deps =
     pexpect
     {env:_PYTEST_TOX_EXTRA_DEP:}
+whitelist_externals = env
 commands =
     {env:_PYTEST_TOX_COVERAGE_RUN:} pytest -ra test_pdb.py test_terminal.py test_unittest.py
 
@@ -89,13 +92,15 @@ changedir=testing
 setenv =
     {[testenv]setenv}
     PYTHONDONTWRITEBYTECODE=1
+whitelist_externals = env
 commands =
     {env:_PYTEST_TOX_COVERAGE_RUN:} pytest -n3 -ra {posargs:.}
 
 [testenv:py27-trial]
 deps =
     twisted
     {env:_PYTEST_TOX_EXTRA_DEP:}
+    whitelist_externals = env
 commands =
     {env:_PYTEST_TOX_COVERAGE_RUN:} pytest -ra {posargs:testing/test_unittest.py}
 
@@ -107,6 +112,7 @@ commands = {[testenv:py27-trial]commands}
 deps =
     numpy
     {env:_PYTEST_TOX_EXTRA_DEP:}
+whitelist_externals = env
 commands=
   {env:_PYTEST_TOX_COVERAGE_RUN:} pytest -ra {posargs:testing/python/approx.py}
 
@@ -144,6 +150,7 @@ skipsdist = True
 deps =
     PyYAML
     {env:_PYTEST_TOX_EXTRA_DEP:}
+whitelist_externals = env
 commands =
     {env:_PYTEST_TOX_COVERAGE_RUN:} pytest -ra doc/en
     {env:_PYTEST_TOX_COVERAGE_RUN:} pytest --doctest-modules --pyargs _pytest