@Test
public void listRoads() throws Exception {

  when(roadAdminClient.listRoads()).thenReturn(ImmutableSortedSet.of("road1", "road2"));
  Set<String> roadNames = underTest.getRoadNames();
  assertThat(roadNames.size(), is(2));
  assertTrue(roadNames.contains("road1"));
  assertTrue(roadNames.contains("road2"));
}