 <p>If you are having problem with validation messages you can always check the codes for the validation errors using the <code>errors</code> collection on an instance.</p> <pre><code>Customer c = ... c.validate() c.errors.each { println it } c.errors.getFieldError("address").codes.each { println it } c.errors.getFieldError("address").defaultMessage </code></pre> <p>Write a unit test to check the codes to localise the messages.</p>