nunit - Unit Testing Insert Empty Record Should Throw Error -

i new unit testing , trying test new employee record should not inserted database. when call context.savechanges() not throw error in unit test, when try out in controller throws error expected.

i guessing employee entity isn't being added context in unit test when call savechanges() nothing being saved? appreciated!

unit test

[test] [expectedexception(typeof(dbentityvalidationexception))] public void shouldnotsaveemptyemployee() {     var mockset = new mock<dbset<employee>>();      var mockcontext = new mock<sqlcontext>();     mockcontext.setup(m => m.employees).returns(mockset.object);      var sut = new employeerepository(mockcontext.object);     sut.save(new employee()); } 

repository:

public void save(employee employee) {     if (employee.employeeid > 0)     {         context.entry(employee).state = entitystate.modified;     }     else     {         context.employees.add(employee);     }      context.savechanges(); } 

when running unit test, context inside employeerepository mocked object , there method savechanges has no implementation. when intiailizing employeerepository should give actual sqlcontext constraint checked. class under test here employeerepository seem testing functionality in sqlcontext. test doesn't seem belong here.