Function test_horizontal_scrolling

repl/src/editor.rs:1530–1615

()

    #[test]
    fn test_horizontal_scrolling() {
        let mut cb = MockConsole::default();
        cb.set_size_chars(yx(10, 40));
        let mut ob = OutputBuilder::new(yx(10, 40));
        ob = ob.refresh(linecol(0, 0), &["ab", "", "xyz"], yx(0, 0));

        cb.add_input_keys(&[Key::ArrowDown]);
        ob = ob.quick_refresh(linecol(1, 0), yx(1, 0));

        // Insert characters until the screen's right boundary.
        for (col, ch) in "123456789012345678901234567890123456789".chars().enumerate() {
            cb.add_input_keys(&[Key::Char(ch)]);
            ob = ob.set_dirty();
            let mut buf = [0u8; 4];
            ob = ob.add(CapturedOut::Write(ch.encode_utf8(&mut buf).to_string()));
            ob = ob.quick_refresh(linecol(1, col + 1), yx(1, u16::try_from(col + 1).unwrap()));
        }

        // Push the insertion line over the right boundary and test that surrounding lines scroll as
        // well.
        cb.add_input_keys(&[Key::Char('A')]);
        ob = ob.refresh(
            linecol(1, 40),
            &["b", "23456789012345678901234567890123456789A", "yz"],
            yx(1, 39),
        );
        cb.add_input_keys(&[Key::Char('B')]);
        ob = ob.refresh(
            linecol(1, 41),
            &["", "3456789012345678901234567890123456789AB", "z"],
            yx(1, 39),
        );
        cb.add_input_keys(&[Key::Char('C')]);
        ob = ob.refresh(
            linecol(1, 42),
            &["", "456789012345678901234567890123456789ABC", ""],
            yx(1, 39),
        );

        // Move back a few characters, without pushing over the left boundary, and then insert two
        // characters: one will cause the insertion line to fill up the empty space left by the
        // cursor and the other will cause the view of the insertion line to be truncated on the
        // right side.
        for (file_col, cursor_col) in &[(41, 38), (40, 37), (39, 36)] {
            cb.add_input_keys(&[Key::ArrowLeft]);
            ob = ob.quick_refresh(linecol(1, *file_col), yx(1, *cursor_col));
        }
        cb.add_input_keys(&[Key::Char('D')]);
        ob = ob.refresh_line(linecol(1, 40), "456789012345678901234567890123456789DABC", yx(1, 37));
        cb.add_input_keys(&[Key::Char('E')]);
        ob = ob.refresh_line(linecol(1, 41), "456789012345678901234567890123456789DEAB", yx(1, 38));

        // Delete a few characters to restore the overflow part of the insertion line.
        cb.add_input_keys(&[Key::Backspace]);
        ob = ob.refresh_line(linecol(1, 40), "456789012345678901234567890123456789DABC", yx(1, 37));
        cb.add_input_keys(&[Key::Backspace]);
        ob = ob.refresh_line(linecol(1, 39), "456789012345678901234567890123456789ABC", yx(1, 36));
        cb.add_input_keys(&[Key::Backspace]);