How to mock Prisma (via Proxy) in Jest 27 - jestjs

Question

Our Prisma setup is as follows:
// server/database/prisma.ts
import { Prisma } from 'database/generated/prisma-client';
const client = new Prisma({
endpoint: PRISMA_ENDPOINT,
secret: PRISMA_SECRET,
debug: PRISMA_DEBUG,
});
// Add a proxy 'middleware' to the Prisma client to record query execution time
const prismaProxy = new Proxy(client, {
get(client, endpoint) {
const endTimer = metrics.prisma_call_duration_seconds.startTimer({ endpoint });
return function (...args) {
const result: Prisma = client[endpoint](...args);
endTimer();
return result;
};
},
});
export const prisma = prismaProxy;
I then have a utility that uses prisma that I would like to test:
// utils.ts
import { prisma } from 'database/prisma';
export const myFunc = async () => {
const result = await prisma.items();
if (items && items.length > 0) {
return true;
}
return false;
};
How do I mock prisma in a test? In Jest 26, this worked:
// utils.test.ts
jest.mock('server/database/prisma');
import { prisma } from 'server/database/prisma';
import { myFunc } from 'server/utils';
describe.only('my test', () => {
beforeAll(() => {
prisma.items.mockImplementation(() =>
Promise.resolve([
{
foo: 'bar',
},
])
);
});
test('it works', async () => {
const items = await myFunc();
expect(items).toBeTruthy();
});
});
This no longer works in Jest 27 it seems. Having made no changes except upgrading Jest from v26 -> v27 the mocks no longer seem to take hold.
What is the proper way to mock prisma here?