fn make_opts(n: usize) -> Vec<SelectOption> {

    (0..n)

        .map(|i| SelectOption {

            id: format!("id-{i}"),

            label: format!("Label {i}"),

        })

        .collect()

}

fn new_has_one_row() {

    let sw = SplitsWidget::new(EditMode::Emacs);

    assert_eq!(sw.rows().len(), 1);

    assert_eq!(sw.row_focus, 0);

    assert_eq!(sw.col_focus, 0);

}

fn add_row_inserts_after_focus() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    sw.add_row();

    assert_eq!(sw.rows().len(), 2);

    assert_eq!(sw.row_focus, 1);

}

fn add_row_three_times() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    sw.add_row();

    sw.add_row();

    sw.add_row();

    assert_eq!(sw.rows().len(), 4);

}

fn remove_row_keeps_at_least_one() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    sw.remove_row();

    assert_eq!(sw.rows().len(), 1);

}

fn remove_row_with_two_rows_leaves_one() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    sw.add_row();

    assert_eq!(sw.rows().len(), 2);

    sw.remove_row();

    assert_eq!(sw.rows().len(), 1);

}

fn remove_row_adjusts_focus_when_at_last() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    sw.add_row();

    sw.add_row();

    assert_eq!(sw.row_focus, 2);

    sw.remove_row();

    assert_eq!(sw.row_focus, 1);

}

fn advance_cell_walks_columns_then_stops_at_last_cell() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    for _ in 0..5 {

        sw.advance_cell();

    }

    assert_eq!(

    assert!(sw.at_last_cell());

    sw.advance_cell(); // no-op at the boundary (caller yields)

    assert_eq!(sw.col_focus, 5);

    assert_eq!(sw.row_focus, 0);

}

fn advance_cell_crosses_into_next_row() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    sw.add_row();

    sw.row_focus = 0;

    sw.col_focus = 5;

    sw.advance_cell();

    assert_eq!(sw.row_focus, 1, "advance from last col steps to next row");

    assert_eq!(sw.col_focus, 0);

}

fn retreat_cell_stops_at_first_cell() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    assert!(sw.at_first_cell());

    sw.retreat_cell(); // no-op at the boundary (caller yields)

    assert_eq!(sw.col_focus, 0);

    assert_eq!(sw.row_focus, 0);

}

fn retreat_cell_crosses_into_previous_row() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    sw.add_row();

    sw.retreat_cell();

    assert_eq!(sw.row_focus, 0);

    assert_eq!(sw.col_focus, 5);

}

fn add_row_inherits_cached_options() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    sw.set_account_options(make_opts(3));

    sw.set_commodity_options(make_opts(2));

    sw.add_row();

    let row = &sw.rows()[1];

    assert_eq!(row.from.option_count(), 3, "new row from-account seeded");

    assert_eq!(row.to.option_count(), 3, "new row to-account seeded");

    assert_eq!(

        row.from_commodity.option_count(),

    assert_eq!(

        row.to_commodity.option_count(),

}

fn render_lines_shows_selected_labels_and_focus_marker() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    sw.set_account_options(make_opts(2));

    let lines = sw.render_lines();

    assert_eq!(lines.len(), 1);

    assert!(

        lines[0].starts_with('▸'),

    assert!(

        lines[0].contains("Label 0"),

    assert!(

        lines[0].contains("[Label 0]"),

}

fn next_row_wraps_single() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    sw.next_row();

    assert_eq!(sw.row_focus, 0);

}

fn next_row_wraps_two() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    sw.add_row();

    sw.row_focus = 0;

    sw.next_row();

    assert_eq!(sw.row_focus, 1);

    sw.next_row();

    assert_eq!(sw.row_focus, 0);

}

fn prev_row_wraps() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    sw.add_row();

    sw.row_focus = 0;

    sw.prev_row();

    assert_eq!(sw.row_focus, 1);

}

fn col_kind_select_for_first_four() {

    assert_eq!(SplitRow::col_kind(COL_FROM), WidgetKind::Select);

    assert_eq!(SplitRow::col_kind(COL_TO), WidgetKind::Select);

    assert_eq!(SplitRow::col_kind(COL_FROM_COMM), WidgetKind::Select);

    assert_eq!(SplitRow::col_kind(COL_TO_COMM), WidgetKind::Select);

}

fn col_kind_amount_for_last_two() {

    assert_eq!(SplitRow::col_kind(COL_VALUE), WidgetKind::Amount);

    assert_eq!(SplitRow::col_kind(COL_TO_AMOUNT), WidgetKind::Amount);

}

fn set_account_options_populates_all_rows() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    sw.add_row();

    sw.set_account_options(make_opts(3));

    for row in sw.rows() {

        assert_eq!(row.from.option_count(), 3);

        assert_eq!(row.to.option_count(), 3);

}

fn set_commodity_options_populates_all_rows() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    sw.add_row();

    sw.set_commodity_options(make_opts(2));

    for row in sw.rows() {

        assert_eq!(row.from_commodity.option_count(), 2);

        assert_eq!(row.to_commodity.option_count(), 2);

}

fn focused_subwidget_kind_follows_col_focus() {

    let mut sw = SplitsWidget::new(EditMode::Emacs);

    sw.col_focus = COL_FROM;

    assert_eq!(sw.focused_subwidget_kind(), WidgetKind::Select);

    sw.col_focus = COL_VALUE;

    assert_eq!(sw.focused_subwidget_kind(), WidgetKind::Amount);

}

fn display_shows_row_and_col() {

    let sw = SplitsWidget::new(EditMode::Emacs);

    let d = sw.display();

    assert!(d.contains("1 split(s)"), "row count: {d}");

    assert!(d.contains("row 0"), "row focus: {d}");

}