I am working on a NextJS+React project and need to write a Unit Test using JestJS that depends on one ENV variable. The variables is named to SITE_BRAND and defaulted to brand value.

I need to test whether a component is rendered properly based on cookies. In the element are a few conditionals checking on some cookies values and outputting accordingly and this is what I am trying to test with JestJS.

I’m trying to test that a function, which is defined inside of a hook, is called in a component that uses that hook/function. I’m familiar with mocking simple modules/functions, but this scenario has me confused as I don’t know how to mock only a single returned function from that hook without losing all of the other functions/logic in that hook, which I don’t want to mock.