Testing Meteor code is very slow when using the built-in
meteor test command.
These stubs will help you get rid of the dependencies which are not present in
node_modules directory. Use the setup below which does most of
the actual magic. :)
npm i -D jest-meteor-stubs or
yarn add -D jest-meteor-stubs
How it works
Jest preprocesses the files to be executed through the test runner. When pulling
in dependencies, i.e. using
require (in ES6
import), similar to the default
behavior of Node.js, the resolver will look for them in a local directory named
node_modules. However, Meteor injects additional modules when running
instead of plain Node.js, which do not reside in this directory. Jest allows you
to overcome this issue by providing additional locations where the load should
look for modules.
Add this module's
lib/ directory to the
modulePaths in your Jest config.
For Meteor packages, you will need to use
moduleNameMapper to rewrite the
module names to use
_ instead of
: for the namespaces as
: is not allowed
by some file/operating systems.
The configuration has to be in
jest.config.js in Jest 20 because of
a bug in the mapper.
Here is a working example:
moduleexports =transform:'^.+\\.jsx?$': 'babel-jest'moduleFileExtensions:'js''jsx'modulePaths:'<rootDir>/node_modules/''<rootDir>/node_modules/jest-meteor-stubs/lib/'moduleNameMapper:'^(.*):(.*)$': '$1_$2'unmockedModulePathPatterns:'/^imports\\/.*\\.jsx?$/''/^node_modules/';
Please see this demo for a small example. :)