Add Travis CI testing

.travis.yml

diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..75721f2
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,7 @@
+language: bash
+before_install:
+  - ./script/install-bats.sh
+before_script:
+  - export PATH="${HOME}/.local/bin:${PATH}"
+script:
+  - bats test

script/install-bats.sh

diff --git a/script/install-bats.sh b/script/install-bats.sh
new file mode 100755
index 0000000..4c3161a
--- /dev/null
+++ b/script/install-bats.sh
@@ -0,0 +1,6 @@
+#!/bin/sh
+set -o errexit
+set -o xtrace
+
+git clone --depth 1 https://github.com/sstephenson/bats
+cd bats && ./install.sh "${HOME}/.local" && cd .. && rm -rf bats