a test with a lot of custom interconenctions between filters

It fails now.

max() and min() are not operable.

"Author => BookNoFK" and "Author => BookNoFKAndNoPK" are failing 'cos LittleORM can't connect those models. When you try to connect model A to model B while model A has primary key definition and has no foreign key definition, and model B has no foreign key definition too, but has _return definition - LittleORM ignores primary key of model A, forcing you to define an accepting column. On the other hand, when accepting column of model A is defined, but there is no _return definition for model B which at the same time has primary key definion - models are connected successfully. Should LittleORM count primary key of model A as an accepting column when there is no such explicit definition, shouldn't it?