Merge haste configs if they are available

[colinta]

Per Slack discussion:

In rules_jest, is "_jest_config_template" meant to be configurable?

(why? config.haste = { enableSymlinks: true } is conflicting with React-native preset's haste: { defaultPlatform: 'ios', platforms: […], } configuration)

@gregmagolan told me to "go do it yourself!" (not his words)

The fix would be to merge the two together. Would be happy to accept a PR for that.

👍

---

Changes are visible to end-users: no

• Searched for relevant documentation and updated as needed: yes
• Breaking change (forces users to change their own code or config): no
• Suggested release notes appear below: yes

jest_test will now preserve your jest.config.js settings.

jest_test(
  …
  config = "jest.config.js",  # previously, `haste` configuration in this file would be overridden
)

Test plan

• Covered by existing test cases
• New test cases added (jest/test/case14*)
• Manual testing; please provide instructions so we can reproduce:

Add haste configuration to jest.config.js, watch it get merged into the defaults { enableSymlinks: true } defined in jest_config_template.mjs

[CLAassistant]

All committers have signed the CLA.

[colinta]

Updated this to include tests:

bazel test //jest/tests:all
INFO: Analyzed 65 targets (0 packages loaded, 84 targets configured).
INFO: Found 52 targets and 13 test targets...
INFO: Elapsed time: 1.434s, Critical Path: 1.25s
INFO: 3 processes: 2 internal, 1 darwin-sandbox.
INFO: Build completed successfully, 3 total actions
//jest/tests:case1                                              (cached) PASSED in 2.6s
//jest/tests:case11a                                            (cached) PASSED in 2.7s
//jest/tests:case11b                                            (cached) PASSED in 2.6s
//jest/tests:case12                                             (cached) PASSED in 2.2s
//jest/tests:case13                                             (cached) PASSED in 1.5s
//jest/tests:case2a                                             (cached) PASSED in 2.0s
//jest/tests:case2b                                             (cached) PASSED in 1.1s
//jest/tests:case5                                              (cached) PASSED in 2.6s
//jest/tests:case6                                              (cached) PASSED in 2.6s
//jest/tests:case7                                              (cached) PASSED in 2.6s
//jest/tests:case8                                              (cached) PASSED in 1.1s
//jest/tests:case9                                              (cached) PASSED in 2.2s
//jest/tests:case14                                                      PASSED in 1.0s

Executed 1 out of 13 tests: 13 tests pass.

Case 14 adds a file case14-lib.foo.js that is not picked up without this patch: https://gist.github.com/colinta/689d5834e52b3ff9e767d4894b58f16a

[gregmagolan]

Thanks for the fix!