Add skip_missing_interpreters to tox.ini.dont-be-pretentious

This way users will not be penalized if they do not have all python
versions installed.

The docs are updated to suggest just calling tox with no arguments.

1 files changed, 4 insertions, 0 deletions

diff --git a/tox.ini b/tox.ini
index fc39d31..55ff47b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -10,6 +10,10 @@ envlist =
 #   docs
 #   release
 
+# Don't error out if a user hasn't installed all python versions.
+skip_missing_interpreters =
+    true
+
 [testenv]
 passenv =
     WITH_EXTRAS