CommitImpl extends BaseSqlPart implements Commit { @Nullable @Override public SqlPart previous() { return null; }  @NotNull @Override FinishedStatement transaction(); @Override void prependTo(@NotNull final RawSqlBuilder builder); @Nullable @Override SqlPart previous();  }
@Test public void previous_returnsNull() { CommitImpl commit = new CommitImpl(); SqlPart result = commit.previous(); assertThat(result, is(nullValue())); }