Doesn't work with jest --projects switch

Issue

Jest 20.0 introduced a --projects flag that allows the test-runner to run multiple projects each with their own independent configs with a single jest instance, including watching. This is very helpful for developing monorepos as well as speeding up CI testing.

When using the --projects flag, the tsconfig.json file path is resolved relative to the project root rather than relative to the current project being tested.

Example

// from /workspace/project-root, with the following package structure
.
└── packages
    ├── package-1
    └── package-2


jest --projects packages/package-1 packages/package-2

ENOENT: no such file or directory, open '/workspace/project-root/tsconfig.test.json'

Expected behavior

The __TS_CONFIG__ var needs to use <rootDir> within it so that we can resolve each tsconfig.json relative to the current project.

In this case we should be resolving the paths /workspace/project-root/packages/package-1/tsconfig.test.json and /workspace/project-root/packages/package-2/tsconfig.test.json.

Minimal reproduction

https://github.com/clayne11/jest-projects-repro

[clayne11]

Reproduction: https://github.com/clayne11/jest-projects-repro

[kulshekhar]

@clayne11 I’ve pushed a change that I think should fix this issue. I’ve tested it against the sample repo and it seems to work (I had to add some content in each package’s tsconfig).

Would it be possible for you to test this (branch fix-238) on a real project as well?