diff --git a/.travis.yml b/.travis.yml
index 288d99e..eb943ac 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -22,6 +22,14 @@ install:
   - "pip install -r requirements.txt --use-mirrors"
   # Install zsh.
   - "sudo apt-get install zsh"
+  # Add PPA if needed
+  - 'if [ "$PPA" != "none" ]; then sudo apt-add-repository -y "$PPA"; sudo apt-get update -qq; fi'
 
 # Run the tests.
 script: "make tests"
+
+env:
+  # Default zsh
+  - PPA = "none"
+  # zsh 5 PPA
+  - PPA = "ppa:brainpower/testing"