jest: [bug] findRelatedTests misses tests, especially in multi-project setups

Do you want to request a feature or report a bug?

bug

What is the current behavior?

Here’s an absolute minimal repo that explains this same test case and can be run directly: https://github.com/paularmstrong/jest-multi-project-example

1. Clone the repo at https://github.com/paularmstrong/jest-multi-project-example
2. Run yarn to install dependencies
3. Run yarn test to ensure tests run
4. Run yarn test --findRelatedTests --listTests projects/bar/bar.js (test is a package script shortcut to jest)

Expectation

We should expect to see the following files as related in the output:

projects/bar/__tests__/index.test.js
projects/foo/__tests__/index.test.js

Actual results

Jest does not appear to resolve related changes across project configurations and we do no receive any listed tests.

Alternatively

If we run yarn test --findRelatedTests --listTests projects/bar/index.js, we do receive only the file for the direct project, bar.

projects/bar/__tests__/index.test.js

Why this is problematic

This is a problem because if we are in a sufficiently large project with many workspaces and many interdependencies, we may make a change to one file in a single workspace and expect to be able to run only the related tests for that change, but none will be run.

We could argue that we should just run all tests, but this can take too long (15+ minutes) to realistically ask people to do every time they make a change.

Environment

Environment:
  OS:  macOS High Sierra 10.13.4
  Node:  8.11.1
  Yarn:  1.6.0
  npm:  5.6.0
  Watchman:  4.7.0
  Xcode:  Xcode 8.1 Build version 8B62
  Android Studio:  Not Found