Adds is_countable polyfill and adds extra PHP test versions

Author: pdscopes

.travis.yml

@@ -6,8 +6,10 @@ php:
   - 7.0
   - 7.1
   - 7.2
+  - 7.3
+  - 7.4
 before_script:
   - COMPOSER_DISCARD_CHANGES=1 composer update --prefer-dist --no-interaction --no-suggest
   - cp phpunit.xml.example phpunit.xml
 script:
-  - vendor/bin/phpunit
+  - vendor/bin/phpunit

src/Validate.php

@@ -4,6 +4,13 @@
 
 use MadeSimple\Arrays\ArrDots;
 
+// Add polyfill in case where running in < PHP 7.3
+if (!function_exists('is_countable')) {
+    function is_countable($var) {
+        return (is_array($var) || $var instanceof Countable);
+    }
+}
+
 class Validate
 {
     /**