Improvements in functional verification of a design are achieved by providing a test template that specifies test parameters directed to a function of the design. An exemption mode of operation is associated with a portion of the template, in which constraints and variables associated with the template are revised. The template is an input to a CSP engine, which, in cooperation with a test generator engine, produces test scenarios that lie in an expanded region of the generator's usual operational space. Provision is made for independently enabling and disabling a plurality of exemption modes of operation that are associated with the same or different areas of the template.