c# - How can I mock up an instance of my main Winform form to test some methods? -

i using moq (which new tdd period). , wanted moq instance of main winforms form test few methods on there. possible? constructor takes object of assembly().

i trying following attempts unsuccessful:

var mockmainform = new mock<mainform>(); mockmainform.setup(x => x.assembler).returns(new assembly()); return mockmainform.object; 

but can't access properties or methods on object once returned. possible do?

but errors ( failed: system.argumentexception : expression not method invocation: x => x.assembler @ moq.expressionextensions.tomethodcall(lambdaexpression expression))

mocking using moq mock interfaces , virtual methods of class. assembler property needs defined virtual.

in case mocking windows form not mocking - has big bag of win32 stuff make tests brittle. if need unit test , mock form, create interface form needs implement , mock objects need interact form.

public interface ihasassembler {     foo assembler {get; set;} }  public class myform : ihasassembler {      // } 

then mock interface , not form:

mock<ihasassembler> mymock = new mock<ihasassembler>();