Below is a test adapted from the test in ogham/rust-term-grid#15. It currently fails in this fork too.

#[test]
fn theoretical_is_effective_max_num_line() {
    let mut grid = Grid::new(GridOptions {
        filling: Filling::Text("||".into()),
        direction: Direction::LeftToRight,
    });

    for s in [
        "test1", "test2", "test3", "test4", "test5", "test6", "test7", "test8", "test9", "test10",
        "test11",
    ] {
        grid.add(Cell::from(s));
    }

    let bits =
        "test1 ||test2 ||test3||test4||test5||test6||test7||test8||test9\ntest10||test11||\n";

    let display = grid.fit_into_width(69).unwrap();
    assert_eq!(display.to_string(), bits);
    assert_eq!(display.row_count(), 2);
}

Expected behaviour:

test1 ||test2 ||test3||test4||test5||test6||test7||test8||test9
test10||test11||

Actual behaviour:

test1||test2||test3||test4 ||test5 ||test6
test7||test8||test9||test10||test11||

This expected behaviour matches the behaviour of GNU ls:

❯ ls --sort=version -x
test1   test2   test3  test4  test5  test6  test7  test8  test9
test10  test11

However, this behaviour changes in the column format:

❯ ls --sort=version
test1  test3  test5  test7  test9   test11
test2  test4  test6  test8  test10

Note how it's not:

test1  test3  test5  test6 test7  test8  test9  test10  test11
test2  test4

We have three options to proceed:

• Settle on one behaviour and document the difference with GNU in uutils/coreutils.
• Make this behaviour configurable regardless of direction.
• Make Direction::LeftToRight fill up as much of the lines and make Direction::TopToBottom fill up columns.

I'd like to coordinate also with the exa folks to determine whether they want to use this fork too and what behaviour they want.