Changing mocha tests to jest tests - jestjs

Question

I'm having trouble changing my mocha tests to jest tests.
I have three test files with three classes: FirstTestGroup, SecondTestGroup and ThirdTestGroup, each with a static execute method, that contains some tests, like this:
class FirstTestGroup {
execute(params) {
describe('some tests', function tests() {
it('one test', () => {
// uses params
});
...
});
...
}
}
Each of those execute methods use the same parameters. These parameters are created in an async before call, like shown bellow.
describe('My Tests', function testSuite() {
let params;
before('param creation', async function asyncFunc() {
// creates params asynchronously
});
it('should pass all', () => {
FirstTestGroup.execute(params);
SecondTestGroup.execute(params);
ThirdTestGroup.execute(params);
});
});
The it('should pass all', ...) is needed because everything inside a describe is run instantly, so params would be passed as null without it. This works in mocha because "it"s can be nested, but apparently this is not the case for jest.
I could make the beforeAll (equivalent of before in jest) be called each time before a test group is run, but I didn't want to do that as this seems inefficient.
I could also place the code inside the before call before the describe('My Tests', ...) is defined. This seems wrong as this should be part of the describe only.
I couldn't find anything in the jest documentation that could help me with that.
Am I doing something wrong? Is there a way to achieve this using jest, even if I have to restructure the tests? But I'd like to keep the tests in different files.
This is my first question here, so please tell me if more info is needed as I'm not used writting here.

Answer 1

Have you tried Jest-Codemods yet?
Jest-Codemods allows you to convert your Mocha, AVA, Jasmine tests into equivalent Jest tests. It would also help you migrate assertion libraries such as Chai and Expect.
The way you do it:
Install jest-codemods with npm install -g jest-codemods
Go to your project and execute jest-codemods
It will ask you Which test library would you like to migrate from?
Select Mocha by using arrow keys (As you want to migrate from Mocha)
Next, It will ask you Will you be using Jest on Node.js as your test runner?
Select Yes, use the globals provided by Jest (recommended)
Last, You need to provide file name on which you are working to migrate from Mocha to Jest.
And you are done!
It will automatically migrate your code from Mocha to Jest. No need to touch code. That's one of the most powerful feature of Jest which would save your time and you don't need to worry about changing mocha tests to jest tests.