Fix `setDefaultNamespace`.
Fix `setDefaultNamespace`.

jubianchi/atoum,mageekguy/atoum,CedCannes/atoum,tejerka/atoum,mageekguy/atoum,agallou/atoum,tejerka/atoum,vonglasow/atoum,gpaton/atoum,gpaton/atoum,GuillaumeDievart/atoum,Tiross/atoum,Tiross/atoum,mikaelrandy/atoum,GuillaumeDievart/atoum,agallou/atoum,vonglasow/atoum,jubianchi/atoum,CedCannes/atoum,mikaelrandy/atoum