The component tests are using React Native Testing Library - https://callstack.github.io/react-native-testing-library/ and Jest - https://jestjs.io/
It is highly recommended to read some advice from Kent C.Dodds on how to write tests and use these tools correctly.
https://kentcdodds.com/blog/common-mistakes-with-react-testing-library
https://www.youtube.com/watch?v=ahrvE062Kv4
Both of these links are showing it for React-Testing-Library (not Native) however the approach is for the most part considered the same.
To run these tests there are two methods.
make test-component
setups and runs the test suite once.
make test-component-watch
setups and runs the test suite and watches for code changes will then retrigger the test suite.
New test files will need their namespace added to either the file "src/quo/core_spec.cljs" or "src/status_im2/core_spec.cljs. These locations may update overtime but it is dependent on the entrypoint in shadow-cljs config discussed below.
For the moment we will keep best practices for tests in our other guidelines document:
To that point these guidelines will follow the conventions of Jest and React Native Testing Library recommendations and Status mobile will just stack their preferences on top.
There is a file of utility functions defined in "src/test_helpers/component.cljs" and "src/test_helpers/component.clj". It will be great to use these utilities and to add any common testing tools to these files as it should make writing tests easier and faster.
Status Mobile has a bespoke tech stack, as such there is more complexities to configuring the tests.
the configuration for compiling our tests are defined in the "shadow-cljs.edn" file.
The three main parts of this are
:target :npm-module
Needed for the configuration we are using
:entries
a vector of entry points for the test files.
and the ns-regexp to specify what tests to find. Since we have multiple forms of tests we decided that "component-spec" is the least likely to detect the wrong file type.
It's worth knowing that our tests are compiled to JS and then run in the temporary folder component-tests.
There is also further configuration for Jest in "test/jest". There is a jest config file which has some mostly standard configuration pieces, where the tests live, what environment variables are set etc. This is documented by Jest here: https://jestjs.io/docs/configuration
There is also a setup file which is used to set some global and default values. Additionally this file is used to mock some of the react native (among other) dependencies.