A worker process has failed to exit gracefully and has been force exited. This is likely caused by tests leaking due to improper teardown code example

Example: jest A worker process has failed to exit gracefully and has been force exited. This is likely caused by tests leaking due to improper teardown. Try running with --detectOpenHandles to find leaks.

Node v12.14.1
Angular 9.1
Jest 25.2.7