Explanation:
When using Jest workers, there is a limit to the number of exceptions or errors that can occur within the child processes before Jest reaches the retry limit and stops running. This limit is set to 5 by default.
In your specific case, Jest encountered 4 child process exceptions, which means that it encountered 4 errors within the worker threads. Since this number does not exceed the retry limit, Jest will attempt to retry running the tests.
However, if the number of child process exceptions exceeds the retry limit (in this case, 5), Jest will no longer retry executing the tests and will stop running, as it is an indication of potential issues with the test environment or test configuration.
Example:
describe("Example Test Suite", () => {
it("Example Test", () => {
expect(2 + 2).toBe(5); // This will result in a child process exception
});
});
In this example, the test tries to assert that 2 + 2 equals 5, which is obviously incorrect. Running this test with Jest will result in a child process exception because the expectation fails. If this exception occurs multiple times and reaches the retry limit, Jest will stop running.