Add tox option testenv-skip-test-extra.

Set this to true if your package does not have a ``test`` extra.
Otherwise tests fail with latest `tox`.
See plone/meta#325

Author: mauritsvanrees

CHANGES.rst

@@ -4,6 +4,10 @@ Change log
 2.2 (unreleased)
 ----------------
 
+- Add tox option ``testenv-skip-test-extra``.
+  Set this to true if your package does not have a ``test`` extra.
+  Otherwise tests fail with latest `tox`.
+
 - Remove special treatment for macOS test runners on GitHub
 
 - Print out a warning if a ``setuptools`` install time dependency is found

docs/narr.rst

@@ -458,6 +458,10 @@ testenv-additional-extras
   Additional entries for the ``extras`` option in ``[testenv]`` of
   ``tox.ini``.  This option has to be a list of strings without indentation.
 
+testenv-skip-test-extra
+  Don't add the standard ``test`` in the ``extras`` option in ``[testenv]``
+  of ``tox.ini``.  This option has to be true/false.  Default is false.
+
 testenv-commands-pre
   Replacement for the default ``commands_pre`` option in ``[testenv]`` of
   ``tox.ini``. This option has to be a list of strings without indentation.

src/zope/meta/config_package.py

@@ -462,6 +462,8 @@ def tox(self):
         testenv_additional = self.tox_option('testenv-additional')
         testenv_additional_extras = self.tox_option(
             'testenv-additional-extras')
+        testenv_skip_test_extra = self.tox_option(
+            'testenv-skip-test-extra', False)
         testenv_commands_pre = self.tox_option('testenv-commands-pre')
         testenv_commands = self.tox_option('testenv-commands')
         testenv_setenv = self.tox_option('testenv-setenv')
@@ -503,6 +505,7 @@ def tox(self):
             lint_diff_on_failure=lint_diff_on_failure,
             testenv_additional=testenv_additional,
             testenv_additional_extras=testenv_additional_extras,
+            testenv_skip_test_extra=testenv_skip_test_extra,
             testenv_commands=testenv_commands,
             testenv_commands_pre=testenv_commands_pre,
             testenv_deps=testenv_deps,

src/zope/meta/default/tox-testenv.j2

@@ -42,7 +42,9 @@ commands =
     sphinx-build -b doctest -d {envdir}/.cache/doctrees docs {envdir}/.cache/doctest
 {% endif %}
 extras =
+  {% if not testenv_skip_test_extra %}
     test
+  {% endif %}
   {% if with_sphinx_doctests %}
     docs
   {% endif %}