Answer Happy

How to write a driver test for this function?
h = figure;
set(h,'KeyPressFcn',@KeyPressCb);
function y = KeyPressCb(~,evnt)
fprintf('key pressed: %s\n',evnt.Key);
global s;
if strcmp(evnt.Key,'rightarrow')==1
s = evnt.Key;
elseif strcmp(evnt.Key, 'leftarrow')==1
s = evnt.Key;
elseif strcmp(evnt.Key,'space')==1
s = evnt.Key;
end
end
end