Generic/ValidFunctionName: improve enum tests

Ensure that all aspects of the sniff are tested for enums.

While these tests pass, if you look at the actual error message output, you will see some weirdness (declaration name for the `enum` set as `string`).
This should be fixed once PR 3534 has been merged.

Author: jrfnl

src/Standards/PEAR/Tests/NamingConventions/ValidFunctionNameUnitTest.inc

@@ -221,7 +221,23 @@ abstract class My_Class {
     public function _MY_CLASS() {}
 }
 
-enum My_Enum {
-    public function my_class() {}
-    public function _MY_CLASS() {}
+enum Suit: string implements Colorful, CardGame {
+    // Magic methods.
+    function __call($name, $args) {}
+    static function __callStatic($name, $args) {}
+    function __invoke() {}
+
+    // Valid Method Name.
+    public function parseMyDSN() {}
+    private function _getAnotherValue() {}
+
+    // Double underscore non-magic methods not allowed.
+    function __myFunction() {}
+    function __my_function() {}
+
+    // Non-camelcase.
+    public function get_some_value() {}
+
+	// Private without underscore prefix.
+    private function getMe() {}
 }

src/Standards/PEAR/Tests/NamingConventions/ValidFunctionNameUnitTest.php

@@ -122,8 +122,10 @@ public function getErrorList()
             212 => 1,
             213 => 1,
             214 => 1,
-            225 => 1,
-            226 => 2,
+            235 => 1,
+            236 => 2,
+            239 => 1,
+            242 => 1,
         ];
 
     }//end getErrorList()