June 2023
Intermediate to advanced
250 pages
4h 40m
English
Content preview from Svelte with Test-Driven Development
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12
Using Component Mocks to Clarify Tests
The preceding chapter introduced the concept of a test double and showed how vi.fn can be used to swap out unwanted behavior within your Vitest test suites. The same technique can be used for Svelte components, but it’s a little more complicated.
Imagine you’re writing unit tests for a component named Parent, and that component itself renders another developer-defined component, named Child. By default, when your tests render Parent, Child is rendered too. But using a component mock can stop that from happening. It swaps out the real Child for a test double.
There are various reasons why you’d want to do this:
- The Child component already has its own unit test suite, and you don’t want to repeat yourself ...
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