Adds PHPCS in Travis CI

.travis.yml

@@ -23,6 +23,7 @@ matrix:
 
 before_script:
   - export PATH="$HOME/.composer/vendor/bin:$PATH"
+  - if [[ $TRAVIS_PHP_VERSION == '7.1' ]]; then composer install; fi
   - bash tests/bin/install.sh woocommerce_test root '' localhost $WP_VERSION
   - bash tests/bin/travis.sh before
 
@@ -31,3 +32,4 @@ script:
 
 after_script:
   - bash tests/bin/travis.sh after
+  - bash tests/bin/phpcs.sh

tests/bin/phpcs.sh

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+
+if [[ $TRAVIS_PHP_VERSION == '7.1' ]]; then
+	composer install
+
+	CHANGED_FILES=`git diff --name-only --diff-filter=ACMR $TRAVIS_COMMIT_RANGE | grep \\\\.php | awk '{print}' ORS=' '`
+	IGNORE="tests/cli/,apigen/,includes/gateways/simplify-commerce/includes/,includes/libraries/,includes/api/legacy/"
+
+	if [ "$CHANGED_FILES" != "" ]
+	then
+		echo "Running Code Sniffer."
+		./vendor/bin/phpcs --ignore=$IGNORE --standard=./phpcs.ruleset.xml --encoding=utf-8 -n -p $CHANGED_FILES
+		if [ $? != 0 ]
+		then
+			exit 1
+		fi
+	fi
+
+	exit $?
+if