using a single let and reassigning it is not that bad, because you still keep your tests isolated (although there's a chance of messing things up), but in your specific case you also crossreference the same variable from different hooks one of which is shared between multiple tests (beforeAll).. In your test files, Jest puts each of these methods and objects into the global environment. Limits on nested mappings and objectsedit. It is the level of testing at which the components of the software are tested. Then we assert (Line 16) that in this case a Paragraph component is rendered with its children being equal to the empty list message. I'll be using single-file components here, and I haven't checked whether splitting them into their own HTML, CSS, or js files works or not, so let's assume you're doing that as well.. First, create a MessageList.vue component under src/components: