Fix missing method implementation on Controller class

Missing method handler implementation for the Controller class seems to have disappeared. Re-added it along with unit tests to make sure it doesn't gets removed again.

Signed-off-by: Dries Vints <dries.vints@gmail.com>
Merge pull request #1665 from driesvints/bugfix/fix-missing-method-on-controller

Fix missing method implementation on Controller class