react-to-markdown/__tests__/renderer-spec.tsx

import * as React from "react";
import { render } from "../src/renderer";

test("should render plain text", () => {
  expect((render("abcd") as string).trim()).toBe("abcd");
});

test("should render numbers as text", () => {
  expect((render(123) as string).trim()).toBe("123");
});

test("should render null and not fail for empty values", () => {
  expect(render(null)).toBe(null);
  expect(render(undefined)).toBe(null);
  expect(render([])).toBe(null);
});

test("should render plain text with simple Function Component", () => {
  function TestComponent() {
    return "abcd";
  }

  // Note: Rendering string from JSX shows TS error (https://github.com/DefinitelyTyped/DefinitelyTyped/issues/20544). This is a workaround.
  expect(
    (render(
      React.createElement((TestComponent as unknown) as React.FunctionComponent)
    ) as string).trim()
  ).toBe("abcd");
});

test("should render plain text with simple Class Component", () => {
  class TestComponent extends React.Component {
    render() {
      return "abcd";
    }
  }

  expect((render(<TestComponent />) as string).trim()).toBe("abcd");
});