create-test-container.ts

import { createFetch } from '@whatwg-node/fetch';

export function createTestContainer(
  fn: (fetchAPI: ReturnType<typeof createFetch>) => void,
  extraFlags: Parameters<typeof createFetch>[0] = {}
) {
  ['default-fetch', 'node-fetch'].forEach(fetchImplementation => {
    describe(fetchImplementation, () => {
      const fetchAPI = createFetch({
        useNodeFetch: fetchImplementation === 'node-fetch',
        ...extraFlags,
      });
      fn(fetchAPI);
    });
  });
}