Need some guidance on the best way to mock models in Jest

[aboyer1013]

I'm struggling to mock Keystone models in Jest, using version 29.6.2. I get this error:
Error: tweak can only work over models, observable objects/arrays, or primitives, but got [object Object] instead

Here's my setup:

// ParentModel.spec.ts

import { ParentModel } from './ParentModel';
import { ChildModel } from './ChildModel';

jest.mock('./ChildModel');

describe('describe', () => {
    it('it', () => {
        const model = new ParentModel({
            child: new ChildModel({}),
        });

        expect(model.child.action()).toBe('mock action');
    });
});

// ParentModel.ts

import {
    model, Model, prop, idProp,
} from 'mobx-keystone';

import { ChildModel } from './ChildModel';

@model('ParentStore')
export class ParentModel extends Model({
    id: idProp,
    child: prop<ChildModel>(),
}) {}

// ChildModel.ts

import {
    model, Model, prop, idProp,
} from 'mobx-keystone';

@model('ChildStore')
export class ChildModel extends Model({
    id: idProp,
    prop: prop(null),
}) {
    action() {
        return 'action';
    }
}

// __mocks__/ChildModel.ts

const original = jest.requireActual<typeof import('../ChildModel')>('../ChildModel');

module.exports = {
    ...original,
    ChildModel: class {
        action() { return 'mock action'; }
    },
};

// jest.config.js

module.exports = {
    testEnvironment: 'jsdom',
    testRegex: '.*(spec)\\.(t|j)sx?$',
    moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx', 'json', 'node', 'scss'],
    setupFilesAfterEnv: ['./jest-setup.ts'],
    roots: [
        '<rootDir>',
    ],
    modulePaths: [
        '<rootDir>/src',
        'node_modules',
    ],
    moduleNameMapper: {
        '\\.module\\.scss$': 'identity-obj-proxy',
        '~j(.*)$': '<rootDir>/src/test/$1',
        '~(.*)$': '<rootDir>/src/$1',
    },
    resolver: '<rootDir>/resolver.js',
    transform: {
        '^.+\\.ts?$': 'ts-jest',
        '^.+\\.(t|j)sx?$': [
            '@swc/jest', {
                jsc: {
                    parser: {
                        syntax: 'typescript',
                        decorators: true,
                        jsx: true,
                        tsx: true,
                    },
                    transform: {
                        react: {
                            runtime: 'automatic',
                        },
                    },
                    loose: false,
                },
            },
        ],
        '.+\\.(scss)$': 'jest-css-modules-transform',
    },
    transformIgnorePatterns: ['/node_modules/'],
};

Any guidance on my approach overall would be appreciated or if you could point to an existing example. Thanks!