ColumnImpl extends BaseSqlPart implements Column { @Nullable @Override public SqlPart previous() { return null; } ColumnImpl(@NotNull final String newColumnName); @Override void prependTo(@NotNull final RawSqlBuilder builder); @Nullable @Override SqlPart previous();  }
@Test public void previous_returnsNull() { ColumnImpl column = new ColumnImpl("test"); SqlPart result = column.previous(); assertThat(result, is(nullValue())); }