You can now remove lower-level failure modes from the coverage of a top-level test definition by disabling selected failure effects on assemblies within the test coverage. For Analysts with not only a good working knowledge of eXpress, but also an adequate understanding of their design, this feature can save an enormous amount of time when defining tests in large, hierarchical systems.
Effective use of this feature requires a thorough understanding of how functions & failure modes propagate within your design. In a nutshell, lower-level dependencies are used to determine the output functions on an upper-level assembly at which that object’s failure effects are visible. Effects associated with the functional path (as determined by upper-level dependencies) can be listed on assemblies during test editing. If you disable one or more of these effects within the test coverage, any lowest-level failure modes that are causes of one or more disabled effects—yet are not causes of any of the enabled effects—will be excluded from the calculated test coverage.
Let’s look at this feature step by step.
Enabling Effect-Based Coverage
Before effect-based coverage can be used, this feature must be enabled throughout your system. The most effective way to do this is to close all models in your system (with the exception of the top-level design). Then select “Test Options…” in the Tests submenu of the main Design menu. On the Test Options dialog, select “Enable Effect-Based Coverage on Assemblies”.
The dialog shown at left will then appear. Use this dialog to specify whether you wish to enable this feature only within the current design, within this level and the next, or within all levels of the system. You will usually want to enable this feature within all levels—it must be enabled at least one level below that in which tests will use effect-based coverage.
