Travis ci

.gitignore

@@ -8,4 +8,5 @@ config.yml
 .idea/
 *.swp
 packaged/
-wpcs/
+wpcs/
+vendor/

.travis.yml

@@ -0,0 +1,34 @@
+language: php
+
+matrix:
+  include:
+    - name: "PHP 5.6 Compatibility Test"
+      php: "5.6"
+      env: TEST_VERSION=5.6
+    - name: "PHP7.0 Compatibility Test"
+      php: "7.0"
+      env: TEST_VERSION=7.0
+    - name: "PHP 7.1 Compatibility Test"
+      php: "7.1"
+      env: TEST_VERSION=7.1
+    - name: "PHP 7.2 Compatibility Test"
+      php: "7.2"
+      env: TEST_VERSION=7.2
+    - name: "PHP 7.3 Compatibility Test"
+      php: "7.3"
+      env: TEST_VERSION=7.3
+  allow_failures:
+    - name: "PHP 5.3 Compatibility Test"
+      php: "5.3"
+      env: TEST_VERSION=5.3
+    - name: "PHP 5.4 Compatibility Test"
+      php: "5.4"
+      env: TEST_VERSION=5.4
+    - name: "PHP 5.5 Compatibility Test"
+      php: "5.5"
+      env: TEST_VERSION=5.5
+
+before_script:
+  - composer install --dev
+script:
+  - vendor/bin/phpcs -p src/ --standard=PHPCompatibility --runtime-set testVersion $TEST_VERSION

composer.json

@@ -12,5 +12,10 @@
     ],
     "require": {
         "composer/installers": "~1.0"
+    },
+    "require-dev": {
+        "squizlabs/php_codesniffer": "*",
+        "wimg/php-compatibility": "*",
+        "dealerdirect/phpcodesniffer-composer-installer": "^0.4.4"
     }
 }

library/enqueue-scripts.php

@@ -22,7 +22,7 @@ function foundationpress_asset_path( $filename ) {
 		if ( file_exists( $manifest_path ) ) {
 			$manifest = json_decode( file_get_contents( $manifest_path ), true );
 		} else {
-			$manifest = [];
+			$manifest = array();
 		}
 
 		if ( array_key_exists( $filename, $manifest ) ) {

phpunit.xml.dist

@@ -0,0 +1,16 @@
+<?xml version="1.0"?>
+<phpunit
+	bootstrap="tests/bootstrap.php"
+	backupGlobals="false"
+	colors="true"
+	convertErrorsToExceptions="true"
+	convertNoticesToExceptions="true"
+	convertWarningsToExceptions="true"
+	>
+	<testsuites>
+		<testsuite>
+			<directory prefix="test-" suffix=".php">./tests/</directory>
+			<exclude>./tests/test-sample.php</exclude>
+		</testsuite>
+	</testsuites>
+</phpunit>