Unit Test is skipping all break points

I've created a class with a funcion and than I've created a unit test to test it. I've than updated somethings on my class and referenced the dll to it on the UnitTest after building the class after the changes. When I run the unit test in debug mode it skips every break point thats on the fucntion in the class, but when I put a break point in the UnitTest it self it shows me an error message saying that the module has change since last time, even after I reference it again. What is wrong? Do I need to rebuild the class and than reference it in the test?