describe('base64Encode', (): void => {
  it('encodes a mixed base64 utf8 string', (): void => {
    expect(
      base64Encode('hello world Приветствую ми 你好')
    ).toEqual('aGVsbG8gd29ybGQg0J/RgNC40LLQtdGC0YHRgtCy0YPRjiDQvNC4IOS9oOWlvQ==');