{"id":11182,"date":"2021-12-10T15:18:59","date_gmt":"2021-12-10T20:18:59","guid":{"rendered":"https:\/\/blogs.mathworks.com\/simulink\/?p=11182"},"modified":"2021-12-10T15:18:59","modified_gmt":"2021-12-10T20:18:59","slug":"subsystem-reference-and-test-harness","status":"publish","type":"post","link":"https:\/\/blogs.mathworks.com\/simulink\/2021\/12\/10\/subsystem-reference-and-test-harness\/","title":{"rendered":"Subsystem Reference and Test Harness"},"content":{"rendered":"
In case you missed it, some time ago I wrote <\/span>this post<\/span><\/a> introducing the <\/span>Subsystem Reference<\/span><\/a>. I really like this feature and the way it allows you to simply store the contents of a Subsystem in a separate file.<\/span><\/div>
Since its initial release in R2019b, a lot of enhancements have been made to the Subsystem Reference and today I want to highlight one I find particularly useful: <\/span>Test Harnesses<\/span><\/a>.<\/span><\/div>

The Challenge<\/span><\/h4>
One recommendation I always give to users developing Simulink models is to try keeping the model in an \"updatable\" state as much as possible. This mostly means doing <\/span>update diagram<\/span><\/a> often (Shortcut: <\/span>Ctrl+D<\/span>). That way, if you make a mistake, you will quickly get an error describing what is wrong. Without that, if you make multiple changes before trying to update the model, the error messages might be more difficult to debug because there can be a combination of multiple inter-related issues.<\/span><\/div>
A Reference Subsystem can be edited in two ways, and both have caveats regarding the above suggestion:<\/span><\/div>