Ensure sniff handles custom nonce verification functions case correctly

Author: rodrigoprimo

WordPress/Sniffs/Security/NonceVerificationSniff.php

@@ -413,6 +413,8 @@ private function set_cache( $filename, $start, $end, $nonce ) {
 	 */
 	protected function mergeFunctionLists() {
 		if ( $this->customNonceVerificationFunctions !== $this->addedCustomNonceFunctions ) {
+			$this->customNonceVerificationFunctions = array_map( 'strtolower', $this->customNonceVerificationFunctions );
+
 			$this->nonceVerificationFunctions = RulesetPropertyHelper::merge_custom_array(
 				$this->customNonceVerificationFunctions,
 				$this->nonceVerificationFunctions

WordPress/Tests/Security/NonceVerificationUnitTest.1.inc

@@ -493,3 +493,11 @@ function ajax_process() {
 
     update_post_meta( (int) $_POST['id'], 'a_key', $_POST['a_value'] );
 }
+
+// phpcs:set WordPress.Security.NonceVerification customNonceVerificationFunctions[] MIXED_case_NAME
+function non_ascii_characters() {
+    MIXED_case_NAME( $_POST['something'] ); // Passing $_POST to ensure the sniff bails correctly for variables inside the nonce verification function.
+
+    update_post_meta( (int) $_POST['id'], 'a_key', $_POST['a_value'] );
+}
+// phpcs:set WordPress.Security.NonceVerification customNonceVerificationFunctions[]