@Repeat
  @Test
  public void testAt() {
    // Edge cases
    assertThrows(() -> instance.at("")).isInstanceOf(IllegalArgumentException.class);

    assertThrows(() -> instance.at((URL) null)).isInstanceOf(IllegalArgumentException.class);

    instance.at(url);

    HttpRequest expectedRequest = HttpRequest.Builder.from(request).usingUrl(url).build();

    verify(stateMachine).executeAsync(expectedRequest, responseClass, onSuccess, onFailure);
  }
 @Test
 public void testToString() {
   String toString = instance.toString();
   assertThat(Strings.isNullOrEmpty(toString), is(false));
 }