@@ -331,6 +331,48 @@ class Invalid:
331331cbook ._define_aliases ({'prop' : ['alias1' ,'alias2' ]})(Invalid )
332332
333333
334+ def test_define_aliases_subclass ():
335+ @cbook ._define_aliases ({'prop' : ['alias' ]})
336+ class Base :
337+ def __init__ (self ):
338+ self .call_count = {'Base:set_prop' :0 }
339+
340+ def set_prop (self ):
341+ self .call_count ['Base:set_prop' ]+= 1
342+
343+ class Derived (Base ):
344+ def __init__ (self ):
345+ super ().__init__ ()
346+ self .call_count ['Derived:set_prop' ]= 0
347+
348+ def set_prop (self ):
349+ self .call_count ['Derived:set_prop' ]+= 1
350+
351+ # Calling original or alias should run the same method.
352+ b = Base ()
353+ b .set_prop ()
354+ assert b .call_count ['Base:set_prop' ]== 1
355+ b .set_alias ()
356+ assert b .call_count ['Base:set_prop' ]== 2
357+
358+ d = Derived ()
359+ # Calling original or alias should run the same derived method.
360+ d .set_prop ()
361+ assert d .call_count ['Base:set_prop' ]== 0
362+ assert d .call_count ['Derived:set_prop' ]== 1
363+ d .set_alias ()
364+ assert d .call_count ['Base:set_prop' ]== 0
365+ assert d .call_count ['Derived:set_prop' ]== 2
366+
367+ # Calling original or alias should run the same base method.
368+ Base .set_prop (d )
369+ assert d .call_count ['Base:set_prop' ]== 1
370+ assert d .call_count ['Derived:set_prop' ]== 2
371+ Base .set_alias (d )
372+ assert d .call_count ['Base:set_prop' ]== 2
373+ assert d .call_count ['Derived:set_prop' ]== 2
374+
375+
334376fail_mapping = (
335377 ({'a' :1 }, {'forbidden' : ('a' )}),
336378 ({'a' :1 }, {'required' : ('b' )}),