@Override
  public Changeset getChangesetForLine(int lineNumber) {
    if (!hasChangesetForLine(lineNumber)) {
      throw new IllegalArgumentException("There's no changeset on line " + lineNumber);
    }
    return lineChangesets[lineNumber - 1];
  }
@Test
  public void get_changeset_for_given_line() {
    ScmInfo scmInfo = createScmInfoWithTwoChangestOnFourLines();

    assertThat(scmInfo.getChangesetForLine(1)).isEqualTo(CHANGESET_1);
    assertThat(scmInfo.getChangesetForLine(2)).isEqualTo(CHANGESET_2);
    assertThat(scmInfo.getChangesetForLine(3)).isEqualTo(CHANGESET_1);
    assertThat(scmInfo.getChangesetForLine(4)).isEqualTo(CHANGESET_1);
  }