Jest: Can't find a root directory while resolving a config file path.

[faustbrian]

What is the current behavior?

The test suite fails to run because it can't properly resolve the path.

Config

module.exports = {
  projects: [{
    displayName: 'unit',
    testMatch: ['**/__tests__/unit/**/*.spec.js']
  }]
}

Execution

jest --projects unit

Error: Can't find a root directory while resolving a config file path.
Provided path to resolve: unit
cwd: /Users/code/project

What is the expected behavior?

I expected that the test suite runs with the specified configuration because when I do jest --showConfig it shows my rootDir as /Users/code/project which should properly resolve testMatch: ['**/__tests__/unit/**/*.spec.js'] to '/Users/code/project/__tests__/unit/**/*.spec.js'.

I also tried to use <rootDir> for the testMatch but the same result and it looks like it tries to resolve the unit as a path instead of looking it up in the jest.config.js?

Am I supposed to put a jest.config.js into every folder and then run jest --projects tests/unit? If that is the case then how is the projects option supposed to be used.

Jest, node, yarn and macOS are the latest versions.

[SimenB]

displayName is just for the name, not a way to run it. Although that would be cool 🙂

--projects on the cli is the same as projects in config, except it can just be paths to different config file, not inline JSON

[faustbrian]

Thanks, figured that after some testing and ended up putting a config into each directory.

[elyobo]

Just to confirm I understand this correctly - there's no way to specify the project to run via the CLI if it's configured using a single config file (e.g. in package.json, jest.config.js etc), but you can specify the test to run (but run all projects by default) by making a separate config file in each project and then referring to those in the main config file, e.g.

package.json snippet

  "jest": {
    "projects": [
      "<rootDir>/jest-test.config.js",
      "<rootDir>/jest-eslint.config.js"
    ]
  }

jest-test.config.js

'use strict';

module.exports = {
  displayName: 'test',
  testPathIgnorePatterns: [
    '/node_modules/',
    '/__tests__/fixtures/',
  ],
};

jest-eslint.config.js

'use strict';

module.exports = {
  runner: 'jest-runner-eslint',
  displayName: 'lint',
  testMatch: ['<rootDir>/**/*.js'],
  testPathIgnorePatterns: [
    '/node_modules/',
  ],
};

It would be nice to avoid scattering the config around like this and still be able to use --projects to indicate the project(s) to run, e.g. by matching the displayName.

[SimenB]

@elyobo Correct. PR welcome for some way of specifying which of the loaded projects to run 🙂

[elyobo]

I'll see if I can find some time! I went ahead and split out the config files, which works fine, it just feels like clutter :D

[MaxMilton]

Would be great to avoid duplication of identical configs in monorepos. Something like a pathMatch option for projects: [] so similar sub projects can be grouped together.

[yozlet]

Thanks for the clarification. Could you please add that same clarification to the docs? Right now, the explanation of --projects is so minimal that I can't tell if it's confusingly ambiguous or just wrong.

[SimenB]

Wanna send a PR for that? :)