docs: function withSandbox (config, fn) {
    return () => {
      const S = {
        mocks: {},
        verify () {
          return this.sandbox.verify();
        },
      };
      beforeEach(function beforeEach () {
        S.sandbox = sinon.createSandbox();
        S.mocks[SANDBOX] = S.sandbox;
        for (let [key, value] of _.toPairs(config.mocks)) {
          S.mocks[key] = S.sandbox.mock(value);
        }
      });
      afterEach(function afterEach () {
        S.sandbox.restore();
        for (let k of _.keys(S.mocks)) {
          delete S.mocks[k];
        }
        delete S.mocks[SANDBOX];
      });
      fn(S);
    };
  }