From 70c50625e9e70ad98ea701ef8051ecbe56026b88 Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Fri, 22 May 2020 11:31:51 -0400
Subject: [PATCH] Ensure virtualenv is upgraded when installing tox. Fixes
 jaraco/path#188.

---
 .travis.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.travis.yml b/.travis.yml
index 37fa499..eed7b0a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,7 +8,8 @@ python:
 cache: pip
 
 install:
-- pip install tox
+# ensure virtualenv is upgraded to avoid issues like jaraco/path#188
+- pip install -U --upgrade-strategy=eager tox
 
 before_script:
   # Enable IPv6. Ref travis-ci/travis-ci#8361