Do code linting in Travis.

.travis.yml

@@ -0,0 +1,34 @@
+language: php
+
+branches:
+  # Only test the master branch and SemVer tags.
+  only:
+    - master
+    - /^[[:digit:]]+\.[[:digit:]]+\.[[:digit:]]+.*$/
+
+matrix:
+  include:
+    - php: 7.1
+      env: dependencies=highest
+    - php: 7.0.11
+    - php: 5.6
+    - php: 5.5
+      env: dependencies=lowest
+
+sudo: false
+
+cache:
+  directories:
+    - $HOME/.composer/cache
+
+before_script:
+  # Do highest/lowest testing by installing dependencies per the 'dependencies' setting
+  - if [ -z "$dependencies" ]; then composer install --prefer-dist; fi;
+  - if [ "$dependencies" = "lowest" ]; then composer update --prefer-dist --prefer-lowest -n; fi;
+  - if [ "$dependencies" = "highest" ]; then composer update --prefer-dist -n; fi;
+
+script:
+  - composer -n test
+
+after_success:
+  - travis_retry php vendor/bin/coveralls -v

README.md

@@ -3,6 +3,8 @@ composer-lock-updater
 
 Run composer-lock-updater in your CI system for bot-powered `composer.lock` pull requests.
 
+[![Build Status](https://travis-ci.org/danielbachhuber/composer-lock-updater.svg?branch=master)](https://travis-ci.org/danielbachhuber/composer-lock-updater)
+
 When you run `clu`, it:
 
 1. Clones a given GitHub repository to a working `/tmp/` directory.

composer.json

@@ -10,6 +10,8 @@
     ],
     "require": {},
     "require-dev": {
+        "satooshi/php-coveralls": "~1",
+        "phpunit/php-code-coverage": "~2|~4",
         "squizlabs/php_codesniffer": "^2.7"
     },
     "bin": [