@Test
public void with_empty_file() throws IOException {

    URL footballFile = getResource("empty.dat");
    FootballFileLineProcessor footballFileLineProcessor = new FootballFileLineProcessor();
    FootballFileReader footballFileReader = new FootballFileReader(footballFile, footballFileLineProcessor);
    SmallestGoalDifference smallestGoalDifference = new SmallestGoalDifference(footballFileReader);
    Optional<String> teamWithMinimumGoalDifference = smallestGoalDifference.teamWithMinimumGoalDifference();
    assertThat(teamWithMinimumGoalDifference).isEmpty();
}