Rhino mocks mocking a call

mockingrhino-mocks

I have a method that I want to test which hits the database. From what I have read this is a perfect oppurtunity to use a mock. However the problem that I am facing is that I pass the object a string and then it creates an object and hits the db with this object i.e.

public void test(string t)
{
   Test t1 = new Test(t);
   db.Save(t1);
}

Then the in the test I have:

using(mockery.Record)
{
   Expect.Call(db.Save( ??? ))
}

The problem being – what do I expect here? A call to:

Expect.call(db.Save(new Test(t))

does not work.

As I am new to mocking this may be an easy question, but any help will be much appreciated.

thanks

Best Answer

Well often you pass the actual instance which you later expect. For example:

public void test(string t)
{
    Test t1 = new Test(t);
    using(mockery.Record)
    {
       Expect.Call(db.Save(t1));
    }
    using(mockery.Playback()
    {       
        db.Save(t1);
    }
    mockery.VerifyAll();
}

But this is maybe to limiting. Then you can actually define criterias which the argument has to fullfill. For example:

using(mockery.Record)
{
   Test instanceToCompare = new Test(t);    
   Expect.Call(db.Save(Arg<Test>.Is.Equal(instanceToCompare)));
}

Or another example:

using(mockery.Record)
{
   Expect.Call(db.Save(Arg<Test>.Matches(t=>t.Name.Length.Equals("Test"))));        
}
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