Partial.tsx

import { mount } from "enzyme";
import { SomeComponent, SomeComponentProps } from "./someComponent";

function mountComponent(props: Partial<SomeComponentProps>): ReactWrapper {
  return mount(
    <SomeComponent variant="normal" title="Test Title" {...props} />
  );
}

describe("SomeComponent", () => {
  test("works like it should", () => {
    const onChangeMock = jest.fn();
    const component = mountComponent({ onChange: onChangeMock });
  });
});