Added some exceptions to the method order in CS

contributing/code/standards.rst

@@ -101,7 +101,10 @@ Structure
 
 * Declare class properties before methods;
 
-* Declare public methods first, then protected ones and finally private ones;
+* Declare public methods first, then protected ones and finally private ones. 
+  The exceptions to this rule are the class constructor and the ``setUp`` and 
+  ``tearDown`` methods of PHPUnit tests, which should always be the first methods
+  to increase readability.
 
 * Use parentheses when instantiating classes regardless of the number of
   arguments the constructor has;