Can't use otherwise in Jest tests

[erkannt]

Been playing with this as I like the simplicity of your approach.

Whenever I use otherwise Jest tests covering that code break. Minimal example in the existing index.spec.ts:

  it("using `otherwise` allows `run` in cases where `when`s are not exhaustive", () => {
    const matcher = match(3 as number | string)
      .when( isString, (_) => "it is string")
      .otherwise(() => 'no case matched, resulting to default')

    type _ = Expect<Equal<typeof matcher, BuiltMatch<string>>>;
    expect(matcher.run()).toBe('no case matched, resulting to default')
  })

This results in the following failure:

  ● match › using `otherwise` allows `run` in cases where `when`s are not exhaustive

    TypeError: Cannot read property 'run' of undefined

      39 |
      40 |     type _ = Expect<Equal<typeof matcher, BuiltMatch<string>>>;
    > 41 |     expect(matcher.run()).toBe('no case matched, resulting to default')
         |                    ^
      42 |   })
      43 | });
      44 |

      at Object.<anonymous> (test/index.spec.ts:41:20)

Commit of this as a skipped test available on my fork.

If you have any ideas how to tackle this I'm happy to tinker and prepare a PR. Currently I'm out of ideas.