JEST Change pre-formatted output from test case - jestjs

Question

I have an application that runs a Jest test suite from the command line, then takes the JSON output, parses it and then fills table in a database as per the output file. The application runs shell command:
npm run all
and in the package.json file the all script looks like this:
"scripts": {
"all": "../node_modules/.bin/jest --json --outputFile=testResults.json",`
......
}
So I get the testResults.json file and I am able to parse it - so far so good.
But during the test case run I would like to add some extra data to the output. Something like details - where the problems is, how to fix it, some troubleshooting information etc. For example to put one more field in :
require('testResults.json').testResults[x].assertionResults[y].details
You see, the detail property is not part of the json output file format. But can I create it from within the test case (pseudo example):
test('Industry code should match ind_full_code', async () => {
result = await stageDb.query(QUERY);
// And here I want to add this custom information to some global property available?
reporter.thisTestCase.assertionResults.details = "Here is what you should do to fix this ...." // <- Ideally this is how easy I imagine it to be.
expect(result.results).toEqual([]);
}, 2 * 100 * 1000)
I just want to give a little bit more information to the QA or whomever on test failure.
In other words I need the option to change the output from within the test case.
I've been looking into custom reporters, but their listeners are passed the same information as to the json reported.

Answer 1

I've found a need for a similar feature in Jest. The ability to add documentation to the test is rarely supported by test frameworks.
However I found a way to do this with the soon to be default runner: Jest Circus. I then made my own Jest Circus environment. A custom Jest Circus environment provides more test events/lifecycles and access to the actual test code that is being ran.
// Example of a custom Jest Circus environment
export default class MyCustomNodeEnvironment extends NodeEnvironment {
handleTestEvent(event: Circus.Event, state: Circus.State) {
if(event.name === 'test_fn_start') {
console.log(event.test.toString())
// will log the actual test code.
}
}
}
// jest.config.js
{
"testEnvironment": "<rootDir>/my-custom-environment.js",
"testRunner": "jest-circus/runner"
}
I then used regex patterns to find comments in the test functions and add them to the Allure report (Allure report demo).
If you'd like to create your own Jest environment and implement this yourself I've made a template repo or if you prefer a gist of a basic Jest Circus environment.
If you like how Allure reports look you should checkout my open source project jest-circus-allure-environment.