### Question:
ImmutableUrl { public String toString() { return mutableUrl.toString(); } ImmutableUrl(String base); private  ImmutableUrl(Url url); ImmutableUrl withPath(String path); ImmutableUrl withParam(String key, String value); String toString();  }### Answer:
@Test public void basicImmutableUrlMakesAString() { String url = new ImmutableUrl("http: assertThat(url, is("http: }
@Test public void assumesHttpAsScheme() { assertThat(new ImmutableUrl("localhost/").toString(), is("http: }