Angular Testing Library
Angular Testing Library
builds on top of
DOM Testing Library
by adding APIs for working with Angular components.
npm install --save-dev @testing-library/angular
The problem
You want to write maintainable tests for your Angular components. As a part of this goal, you want your tests to avoid including implementation details of your components and rather focus on making your tests give you the confidence for which they are intended. As part of this, you want your testbase to be maintainable in the long run so refactors of your components (changes to implementation but not functionality) don't break your tests and slow you and your team down.
This solution
The Angular Testing Library
is a very lightweight solution for testing Angular
components. It provides light utility functions on top of
DOM Testing Library
in a way that encourages better testing practices. Its primary guiding principle
is:
The more your tests resemble the way your software is used, the more confidence they can give you.
So rather than dealing with instances of rendered Angular components, your tests
will work with actual DOM nodes. The utilities this library provides facilitate
querying the DOM in the same way the user would. Finding for elements by their
label text (just like a user would), finding links and buttons from their text
(like a user would). It also exposes a recommended way to find elements by a
data-testid
as an "escape hatch" for elements where the text content and label
do not make sense or is not practical.
This library encourages your applications to be more accessible and allows you to get your tests closer to using your components the way a user will, which allows your tests to give you more confidence that your application will work when a real user uses it.
The Angular Testing Library
:
- Re-exports the
query
andfireEvent
utility functions fromDOM Testing Library
. - Encapsulates the
fireEvent
functions of your component to automatically calldetectChanges()
after an event occurs - Is test framework agnostic, it runs on every test framework