c# - Use of rhino mocks to return specific results based on a provided Expression -

i use generic repository access data in c#, method signature of this:

public virtual ienumerable<tentity> get(     expression<func<tentity, bool>> filter = null,     func<iqueryable<tentity>, iorderedqueryable<tentity>> orderby = null,     string includeproperties = "") 

this used in mvc controller (for example) in following ways

var users = unitofwork.userrepository.get(     u => u.id == userid, null, "createdemployer,createdemployer.createdbyuser");  var checkuser = unitofwork.userrepository.get(u => u.username == email)                                          .firstordefault(); 

i want able mock these calls using rhinomocks , receive specific results based on expression called. pseudo code below demonstrates want achieve e.g.

unitofwork.userrepository.expect(     u => u.get(arg<expression<func<user, bool>>>.matches(u.username == "jim")))                          .return(new list<user>() { userjim });  unitofwork.userrepository.expect(     u => u.get(arg<expression<func<user, bool>>>.matches(u.username == "jo left ages ago")))                          .return(new list<user>() ); 

i have tried using .whencalled not seem have behaviour want when matching provided exact provided expression, return specific data:

.whencalled(invocation => {     var predicate = invocation.arguments.first() expression<func<user, bool>>;     ... here }) 

i've been trawling internet while on have not managed dig decent solution, of solutions consist of ignoring arguments works long call repo once in method e.g.

userrepository.expect(u => u.get()).ignorearguments()               .return(new list<user> { currentuser }); 

this has proved inadequate , need bit more robust , specific. interested in first argument. need solution above if solution not exist rhinomocks i'd interested in mocking framework testing expressions easier achieve.

i have answered similar question using moq. can use same approach rhino.

the key use real (or mocked) data set, , run expressions against it.