Terminal compatibility: Pass vttest 2 and 3 (#447)

* fix(compatibility): pass vttest 2+3

* style(fmt): rustfmt

* style(comment): remove unused

* docs(changelog): update change

19 files changed, 925 insertions, 37 deletions

diff --git a/src/client/panes/grid.rs b/src/client/panes/grid.rs
index 162af1e6..e0d460d2 100644
--- a/src/client/panes/grid.rs
+++ b/src/client/panes/grid.rs
@@ -1,6 +1,6 @@
 use std::{
     cmp::Ordering,
-    collections::VecDeque,
+    collections::{BTreeSet, VecDeque},
     fmt::{self, Debug, Formatter},
 };
 
@@ -10,7 +10,8 @@ const SCROLL_BACK: usize = 10_000;
 use crate::utils::logging::debug_log_to_file;
 
 use crate::panes::terminal_character::{
-    CharacterStyles, TerminalCharacter, EMPTY_TERMINAL_CHARACTER,
+    CharacterStyles, CharsetIndex, Cursor, StandardCharset, TerminalCharacter,
+    EMPTY_TERMINAL_CHARACTER,
 };
 
 fn get_top_non_canonical_rows(rows: &mut Vec<Row>) -> Vec<Row> {
@@ -150,18 +151,34 @@ fn bounded_push(vec: &mut VecDeque<Row>, value: Row) {
     vec.push_back(value)
 }
 
+pub fn create_horizontal_tabstops(columns: usize) -> BTreeSet<usize> {
+    let mut i = TABSTOP_WIDTH;
+    let mut horizontal_tabstops = BTreeSet::new();
+    loop {
+        if i > columns {
+            break;
+        }
+        horizontal_tabstops.insert(i);
+        i += TABSTOP_WIDTH;
+    }
+    horizontal_tabstops
+}
+
 #[derive(Clone)]
 pub struct Grid {
     lines_above: VecDeque<Row>,
     viewport: Vec<Row>,
     lines_below: Vec<Row>,
+    horizontal_tabstops: BTreeSet<usize>,
     alternative_lines_above_viewport_and_cursor: Option<(VecDeque<Row>, Vec<Row>, Cursor)>,
     cursor: Cursor,
+    saved_cursor_position: Option<Cursor>,
     scroll_region: Option<(usize, usize)>,
-    pending_styles: CharacterStyles,
+    active_charset: CharsetIndex,
     pub should_render: bool,
     pub cursor_key_mode: bool, // DECCKM - when set, cursor keys should send ANSI direction codes (eg. "OD") instead of the arrow keys (eg. "")
     pub erasure_mode: bool,    // ERM
+    pub disable_linewrap: bool,
     pub clear_viewport_before_rendering: bool,
     pub width: usize,
     pub height: usize,
@@ -186,31 +203,67 @@ impl Grid {
             lines_above: VecDeque::with_capacity(SCROLL_BACK),
             viewport: vec![Row::new().canonical()],
             lines_below: vec![],
+            horizontal_tabstops: create_horizontal_tabstops(columns),
             cursor: Cursor::new(0, 0),
+            saved_cursor_position: None,
             scroll_region: None,
             width: columns,
             height: rows,
-            pending_styles: CharacterStyles::new(),
             should_render: true,
             cursor_key_mode: false,
             erasure_mode: false,
+            disable_linewrap: false,
             alternative_lines_above_viewport_and_cursor: None,
             clear_viewport_before_rendering: false,
+            active_charset: Default::default(),
         }
     }
     pub fn contains_widechar(&self) -> bool {
         self.viewport.iter().any(|c| c.contains_widechar())
     }
     pub fn advance_to_next_tabstop(&mut self, styles: CharacterStyles) {
-        let columns_until_next_tabstop = TABSTOP_WIDTH - (self.cursor.x % TABSTOP_WIDTH);
-        let columns_until_screen_end = (self.width - self.cursor.x).saturating_sub(1);
-        let columns_to_advance =
-            std::cmp::min(columns_until_next_tabstop, columns_until_screen_end);
+        let mut next_tabstop = None;
+        for tabstop in self.horizontal_tabstops.iter() {
+            if *tabstop > self.cursor.x {
+                next_tabstop = Some(tabstop);
+                break;
+            }
+        }
+        match next_tabstop {
+            Some(tabstop) => {
+                self.cursor.x = *tabstop;
+            }
+            None => {
+                self.cursor.x = self.width.saturating_sub(1);
+            }
+        }
         let mut empty_character = EMPTY_TERMINAL_CHARACTER;
         empty_character.styles = styles;
-        self.cursor.x += columns_to_advance;
         self.pad_current_line_until(self.cursor.x);
     }
+    fn set_horizontal_tabstop(&mut self) {
+        self.horizontal_tabstops.insert(self.cursor.x);
+    }
+    fn clear_tabstop(&mut self, position: usize) {
+        self.horizontal_tabstops.remove(&position);
+    }
+    fn clear_all_tabstops(&mut self) {
+        self.horizontal_tabstops.clear();
+    }
+    fn save_cursor_position(&mut self) {
+        self.saved_cursor_position = Some(self.cursor.clone());
+    }
+    fn restore_cursor_position(&mut self) {
+        if let Some(saved_cursor_position) = self.saved_cursor_position.as_ref() {
+            self.cursor = saved_cursor_position.clone();
+        }
+    }
+    fn configure_charset(&mut self, charset: StandardCharset, index: CharsetIndex) {
+        self.cursor.charsets[index] = charset;
+    }
+    fn set_active_charset(&mut self, index: CharsetIndex) {
+        self.active_charset = index;
+    }
     fn cursor_canonical_line_index(&self) -> usize {
         let mut cursor_canonical_line_index = 0;
         let mut canonical_lines_traversed = 0;
@@ -567,6 +620,9 @@ impl Grid {
     pub fn add_character(&mut self, terminal_character: TerminalCharacter) {
         // TODO: try to separate adding characters from moving the cursors in this function
         if self.cursor.x >= self.width {
+            if self.disable_linewrap {
+                return;
+            }
             // line wrap
             self.cursor.x = 0;
             if self.cursor.y == self.height - 1 {
@@ -676,6 +732,13 @@ impl Grid {
         }
     }
     pub fn move_cursor_up(&mut self, count: usize) {
+        if let Some((scroll_region_top, scroll_region_bottom)) = self.scroll_region {
+            if self.cursor.y >= scroll_region_top && self.cursor.y <= scroll_region_bottom {
+                self.cursor.y =
+                    std::cmp::max(self.cursor.y.saturating_sub(count), scroll_region_top);
+                return;
+            }
+        }
         self.cursor.y = if self.cursor.y < count {
             0
         } else {
@@ -702,6 +765,12 @@ impl Grid {
         }
     }
     pub fn move_cursor_down(&mut self, count: usize, pad_character: TerminalCharacter) {
+        if let Some((scroll_region_top, scroll_region_bottom)) = self.scroll_region {
+            if self.cursor.y >= scroll_region_top && self.cursor.y <= scroll_region_bottom {
+                self.cursor.y = std::cmp::min(self.cursor.y + count, scroll_region_bottom);
+                return;
+            }
+        }
         let lines_to_add = if self.cursor.y + count > self.height - 1 {
             (self.cursor.y + count) - (self.height - 1)
         } else {
@@ -841,16 +910,21 @@ impl Grid {
         self.scroll_region = None;
         self.clear_viewport_before_rendering = true;
         self.cursor = Cursor::new(0, 0);
+        self.saved_cursor_position = None;
+        self.active_charset = Default::default();
+        self.erasure_mode = false;
+        self.disable_linewrap = false;
     }
 }
 
 impl vte::Perform for Grid {
     fn print(&mut self, c: char) {
+        let c = self.cursor.charsets[self.active_charset].map(c);
         // apparently, building TerminalCharacter like this without a "new" method
         // is a little faster
         let terminal_character = TerminalCharacter {
             character: c,
-            styles: self.pending_styles,
+            styles: self.cursor.pending_styles,
         };
         self.add_character(terminal_character);
     }
@@ -863,17 +937,23 @@ impl vte::Perform for Grid {
             }
             9 => {
                 // tab
-                self.advance_to_next_tabstop(self.pending_styles);
+                self.advance_to_next_tabstop(self.cursor.pending_styles);
             }
             10 | 11 => {
                 // 0a, newline
-                // 0b, form-feed
+                // 0b, vertical tabulation
                 self.add_newline();
             }
             13 => {
                 // 0d, carriage return
                 self.move_cursor_to_beginning_of_line();
             }
+            14 => {
+                self.set_active_charset(CharsetIndex::G1);
+            }
+            15 => {
+                self.set_active_charset(CharsetIndex::G0);
+            }
             _ => {}
         }
     }
@@ -896,7 +976,9 @@ impl vte::Perform for Grid {
 
     fn csi_dispatch(&mut self, params: &[i64], _intermediates: &[u8], _ignore: bool, c: char) {
         if c == 'm' {
-            self.pending_styles.add_style_from_ansi_params(params);
+            self.cursor
+                .pending_styles
+                .add_style_from_ansi_params(params);
         } else if c == 'C' {
             // move cursor forward
             let move_by = if params[0] == 0 {
@@ -909,11 +991,11 @@ impl vte::Perform for Grid {
             // clear line (0 => right, 1 => left, 2 => all)
             if params[0] == 0 {
                 let mut char_to_replace = EMPTY_TERMINAL_CHARACTER;
-                char_to_replace.styles = self.pending_styles;
+                char_to_replace.styles = self.cursor.pending_styles;
                 self.replace_characters_in_line_after_cursor(char_to_replace);
             } else if params[0] == 1 {
                 let mut char_to_replace = EMPTY_TERMINAL_CHARACTER;
-                char_to_replace.styles = self.pending_styles;
+                char_to_replace.styles = self.cursor.pending_styles;
                 self.replace_characters_in_line_before_cursor(char_to_replace);
             } else if params[0] == 2 {
                 self.clear_cursor_line();
@@ -921,7 +1003,7 @@ impl vte::Perform for Grid {
         } else if c == 'J' {
             // clear all (0 => below, 1 => above, 2 => all, 3 => saved)
             let mut char_to_replace = EMPTY_TERMINAL_CHARACTER;
-            char_to_replace.styles = self.pending_styles;
+            char_to_replace.styles = self.cursor.pending_styles;
             if params[0] == 0 {
                 self.clear_all_after_cursor(char_to_replace);
             } else if params[0] == 1 {
@@ -1008,6 +1090,9 @@ impl vte::Perform for Grid {
                     Some(&6) => {
                         self.erasure_mode = false;
                     }
+                    Some(&7) => {
+                        self.disable_linewrap = true;
+                    }
                     _ => {}
                 };
             }
@@ -1048,6 +1133,9 @@ impl vte::Perform for Grid {
                     Some(&6) => {
                         self.erasure_mode = true;
                     }
+                    Some(&7) => {
+                        self.disable_linewrap = false;
+                    }
                     _ => {}
                 };
             }
@@ -1057,6 +1145,10 @@ impl vte::Perform for Grid {
                 let top_line_index = (params[0] as usize).saturating_sub(1);
                 let bottom_line_index = (params[1] as usize).saturating_sub(1);
                 self.set_scroll_region(top_line_index, bottom_line_index);
+                if self.erasure_mode {
+                    self.move_cursor_to_line(top_line_index, EMPTY_TERMINAL_CHARACTER);
+                    self.move_cursor_to_beginning_of_line();
+                }
                 self.show_cursor();
             } else {
                 self.clear_scroll_region();
@@ -1088,6 +1180,12 @@ impl vte::Perform for Grid {
                 params[0] as usize - 1
             };
             self.move_cursor_to_column(column);
+        } else if c == 'g' {
+            if params[0] == 0 {
+                self.clear_tabstop(self.cursor.x);
+            } else if params[0] == 3 {
+                self.clear_all_tabstops();
+            }
         } else if c == 'd' {
             // goto line
             let line = if params[0] == 0 {
@@ -1105,7 +1203,7 @@ impl vte::Perform for Grid {
             } else {
                 params[0] as usize
             };
-            self.erase_characters(count, self.pending_styles);
+            self.erase_characters(count, self.cursor.pending_styles);
         } else if c == 'X' {
             // erase characters and replace with empty characters of current style
             let count = if params[0] == 0 {
@@ -1113,7 +1211,7 @@ impl vte::Perform for Grid {
             } else {
                 params[0] as usize
             };
-            self.replace_with_empty_chars(count, self.pending_styles);
+            self.replace_with_empty_chars(count, self.cursor.pending_styles);
         } else if c == 'T' {
             /*
              * 124  54  T   SD
@@ -1136,6 +1234,10 @@ impl vte::Perform for Grid {
                 params[0] as usize
             };
             self.rotate_scroll_region_down(count);
+        } else if c == 's' {
+            self.save_cursor_position();
+        } else if c == 'u' {
+            self.restore_cursor_position();
         } else if c == '@' {
             let count = if params[0] == 0 {
                 1
@@ -1153,6 +1255,35 @@ impl vte::Perform for Grid {
 
     fn esc_dispatch(&mut self, intermediates: &[u8], _ignore: bool, byte: u8) {
         match (byte, intermediates.get(0)) {
+            (b'B', charset_index_symbol) => {
+                let charset_index: CharsetIndex = match charset_index_symbol {
+                    Some(b'(') => CharsetIndex::G0,
+                    Some(b')') => CharsetIndex::G1,
+                    Some(b'*') => CharsetIndex::G2,
+                    Some(b'+') => CharsetIndex::G3,
+                    _ => {
+                        // invalid, silently do nothing
+                        return;
+                    }
+                };
+                self.configure_charset(StandardCharset::Ascii, charset_index);
+            }
+            (b'0', charset_index_symbol) => {
+                let charset_index: CharsetIndex = match charset_index_symbol {
+                    Some(b'(') => CharsetIndex::G0,
+                    Some(b')') => CharsetIndex::G1,
+                    Some(b'*') => CharsetIndex::G2,
+                    Some(b'+') => CharsetIndex::G3,
+                    _ => {
+                        // invalid, silently do nothing
+                        return;
+                    }
+                };
+                self.configure_charset(
+                    StandardCharset::SpecialCharacterAndLineDrawing,
+                    charset_index,
+                );
+            }
             (b'D', None) => {
                 self.add_newline();
             }
@@ -1167,7 +1298,13 @@ impl vte::Perform for Grid {
                 self.reset_terminal_state();
             }
             (b'H', None) => {
-                self.advance_to_next_tabstop(self.pending_styles);
+                self.set_horizontal_tabstop();
+            }
+            (b'7', None) => {
+                self.save_cursor_position();
+            }
+            (b'8', None) => {
+                self.restore_cursor_position();
             }
             (b'8', Some(b'#')) => {
                 let mut fill_character = EMPTY_TERMINAL_CHARACTER;
@@ -1311,23 +1448,6 @@ impl Row {
     }
 }
 
-#[derive(Clone, Debug)]
-pub struct Cursor {
-    x: usize,
-    y: usize,
-    is_hidden: bool,
-}
-
-impl Cursor {
-    pub fn new(x: usize, y: usize) -> Self {
-        Cursor {
-            x,
-            y,
-            is_hidden: false,
-        }
-    }
-}
-
 #[cfg(test)]
 #[path = "./unit/grid_tests.rs"]
 mod grid_tests;
diff --git a/src/client/panes/terminal_character.rs b/src/client/panes/terminal_character.rs
index 94620bba..31e017b1 100644
--- a/src/client/panes/terminal_character.rs
+++ b/src/client/panes/terminal_character.rs
@@ -1,7 +1,8 @@
 use unicode_width::UnicodeWidthChar;
 
 use crate::utils::logging::debug_log_to_file;
-use ::std::fmt::{self, Debug, Display, Formatter};
+use std::fmt::{self, Debug, Display, Formatter};
+use std::ops::{Index, IndexMut};
 
 pub const EMPTY_TERMINAL_CHARACTER: TerminalCharacter = TerminalCharacter {
     character: ' ',
@@ -625,6 +626,115 @@ impl Display for CharacterStyles {
     }
 }
 
+#[derive(Clone, Copy, Debug)]
+pub enum CharsetIndex {
+    G0,
+    G1,
+    G2,
+    G3,
+}
+
+impl Default for CharsetIndex {
+    fn default() -> Self {
+        CharsetIndex::G0
+    }
+}
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum StandardCharset {
+    Ascii,
+    SpecialCharacterAndLineDrawing,
+}
+
+impl Default for StandardCharset {
+    fn default() -> Self {
+        StandardCharset::Ascii
+    }
+}
+
+impl StandardCharset {
+    /// Switch/Map character to the active charset. Ascii is the common case and
+    /// for that we want to do as little as possible.
+    #[inline]
+    pub fn map(self, c: char) -> char {
+        match self {
+            StandardCharset::Ascii => c,
+            StandardCharset::SpecialCharacterAndLineDrawing => match c {
+                '`' => '◆',
+                'a' => '▒',
+                'b' => '␉',
+                'c' => '␌',
+                'd' => '␍',
+                'e' => '␊',
+                'f' => '°',
+                'g' => '±',
+                'h' => '␤',
+                'i' => '␋',
+                'j' => '┘',
+                'k' => '┐',
+                'l' => '┌',
+                'm' => '└',
+                'n' => '┼',
+                'o' => '⎺',
+                'p' => '⎻',
+                'q' => '─',
+                'r' => '⎼',
+                's' => '⎽',
+                't' => '├',
+                'u' => '┤',
+                'v' => '┴',
+                'w' => '┬',
+                'x' => '│',
+                'y' => '≤',
+                'z' => '≥',
+                '{' => 'π',
+                '|' => '≠',
+                '}' => '£',
+                '~' => '·',
+                _ => c,
+            },
+        }
+    }
+}
+
+#[derive(Debug, Default, Copy, Clone, PartialEq, Eq)]
+pub struct Charsets([StandardCharset; 4]);
+
+impl Index<CharsetIndex> for Charsets {
+    type Output = StandardCharset;
+
+    fn index(&self, index: CharsetIndex) -> &StandardCharset {
+        &self.0[index as usize]
+    }
+}
+
+impl IndexMut<CharsetIndex> for Charsets {
+    fn index_mut(&mut self, index: CharsetIndex) -> &mut StandardCharset {
+        &mut self.0[index as usize]
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct Cursor {
+    pub x: usize,
+    pub y: usize,
+    pub is_hidden: bool,
+    pub pending_styles: CharacterStyles,
+    pub charsets: Charsets,
+}
+
+impl Cursor {
+    pub fn new(x: usize, y: usize) -> Self {
+        Cursor {
+            x,
+            y,
+            is_hidden: false,
+            pending_styles: CharacterStyles::new(),
+            charsets: Default::default(),
+        }
+    }
+}
+
 #[derive(Clone, Copy)]
 pub struct TerminalCharacter {
     pub character: char,
diff --git a/src/client/panes/unit/grid_tests.rs b/src/client/panes/unit/grid_tests.rs
index 92f5fbdf..f2de7d56 100644
--- a/src/client/panes/unit/grid_tests.rs
+++ b/src/client/panes/unit/grid_tests.rs
@@ -83,3 +83,195 @@ fn vttest1_5() {
     }
     assert_snapshot!(format!("{:?}", grid));
 }
+
+#[test]
+fn vttest2_0() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(41, 110);
+    let fixture_name = "vttest2-0";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
+fn vttest2_1() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(41, 110);
+    let fixture_name = "vttest2-1";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
+fn vttest2_2() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(41, 110);
+    let fixture_name = "vttest2-2";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
+fn vttest2_3() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(41, 110);
+    let fixture_name = "vttest2-3";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
+fn vttest2_4() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(41, 110);
+    let fixture_name = "vttest2-4";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
+fn vttest2_5() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(41, 110);
+    let fixture_name = "vttest2-5";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
+fn vttest2_6() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(41, 110);
+    let fixture_name = "vttest2-6";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
+fn vttest2_7() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(41, 110);
+    let fixture_name = "vttest2-7";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
+fn vttest2_8() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(41, 110);
+    let fixture_name = "vttest2-8";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
+fn vttest2_9() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(41, 110);
+    let fixture_name = "vttest2-9";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
+fn vttest2_10() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(41, 110);
+    let fixture_name = "vttest2-10";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
+fn vttest2_11() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(41, 110);
+    let fixture_name = "vttest2-11";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
+fn vttest2_12() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(41, 110);
+    let fixture_name = "vttest2-12";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
+fn vttest2_13() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(41, 110);
+    let fixture_name = "vttest2-13";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
+fn vttest2_14() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(41, 110);
+    let fixture_name = "vttest2-14";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
+
+#[test]
+fn vttest3_0() {
+    let mut vte_parser = vte::Parser::new();
+    let mut grid = Grid::new(41, 110);
+    let fixture_name = "vttest3-0";
+    let content = read_fixture(fixture_name);
+    for byte in content {
+        vte_parser.advance(&mut grid, byte);
+    }
+    assert_snapshot!(format!("{:?}", grid));
+}
diff --git a/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_0.snap b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_0.snap
new file mode 100644
index 00000000..506c2226
--- /dev/null
+++ b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_0.snap
@@ -0,0 +1,28 @@
+---
+source: src/client/panes/./unit/grid_tests.rs
+expression: "format!(\"{:?}\", grid)"
+
+---
+00 (C): **************************************************************************************************************
+01 (C): **************************************************                                                            
+02 (C): **************************************************************************************************************
+03 (C):                                                                                                               
+04 (C): This should be three identical lines of *'s completely filling                                                
+05 (C): the top of the screen without any empty lines between.                                                        
+06 (C): (Test of WRAP AROUND mode setting.)                                                                           
+07 (C): Push <RETURN>                                                                                                 
+08 (C):                                                                                                               
+09 (C):                                                                                                               
+10 (C):                                                                                                               
+11 (C):                                                                                                               
+12 (C):                                                                                                               
+13 (C):                                                                                                               
+14 (C):                                                                                                               
+15 (C):                                                                                                               
+16 (C):                                                                                                               
+17 (C):                                                                                                               
+18 (C):                                                                                                               
+19 (C):                                                                                                               
+20 (C):                                                                                                               
+21 (C):                                                                                                               
+
diff --git a/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_1.snap b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_1.snap
new file mode 100644
index 00000000..48e47687
--- /dev/null
+++ b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_1.snap
@@ -0,0 +1,28 @@
+---
+source: src/client/panes/./unit/grid_tests.rs
+expression: "format!(\"{:?}\", grid)"
+
+---
+00 (C):       *     *     *     *     *     *     *     *     *     *     *     *     *                               
+01 (C):       *     *     *     *     *     *     *     *     *     *     *     *     *                               
+02 (C):                                                                                                               
+03 (C): Test of TAB setting/resetting. These two lines                                                                
+04 (C): should look the same. Push <RETURN>                                                                           
+05 (C):                                                                                                               
+06 (C):                                                                                                               
+07 (C):                                                                                                               
+08 (C):                                                                                                               
+09 (C):                                                                                                               
+10 (C):                                                                                                               
+11 (C):                                                                                                               
+12 (C):                                                                                                               
+13 (C):                                                                                                               
+14 (C):                                                                                                               
+15 (C):                                                                                                               
+16 (C):                                                                                                               
+17 (C):                                                                                                               
+18 (C):                                                                                                               
+19 (C):                                                                                                               
+20 (C):                                                                                                               
+21 (C):                                                                                                               
+
diff --git a/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_10.snap b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_10.snap
new file mode 100644
index 00000000..dbacac54
--- /dev/null
+++ b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_10.snap
@@ -0,0 +1,30 @@
+---
+source: src/client/panes/./unit/grid_tests.rs
+expression: "format!(\"{:?}\", grid)"
+
+---
+00 (W):                                                                                                               
+01 (W):                                                                                                               
+02 (W):                                                                                                               
+03 (W):                                                                                                               
+04 (W):                                                                                                               
+05 (W):                                                                                                               
+06 (W):                                                                                                               
+07 (W):                                                                                                               
+08 (W):                                                                                                               
+09 (W):                                                                                                               
+10 (W):                                                                                                               
+11 (W):                                                                                                               
+12 (W):                                                                                                               
+13 (W):                                                                                                               
+14 (W):                                                                                                               
+15 (W):                                                                                                               
+16 (W):                                                                                                               
+17 (W):                                                                                                               
+18 (W):                                                                                                               
+19 (W):                                                                                                               
+20 (W):                                                                                                               
+21 (W):                                                                                                               
+22 (W): This line should be the one above the bottom of the screen. Push <RETURN>                                     
+23 (W): Origin mode test. This line should be at the bottom of the screen.                                            
+
diff --git a/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_11.snap b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_11.snap
new file mode 100644
index 00000000..3c424d45
--- /dev/null
+++ b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_11.snap
@@ -0,0 +1,30 @@
+---
+source: src/client/panes/./unit/grid_tests.rs
+expression: "format!(\"{:?}\", grid)"
+
+---
+00 (W): This line should be at the top of the screen. Push <RETURN>                                                   
+01 (W):                                                                                                               
+02 (W):                                                                                                               
+03 (W):                                                                                                               
+04 (W):                                                                                                               
+05 (W):                                                                                                               
+06 (W):                                                                                                               
+07 (W):                                                                                                               
+08 (W):                                                                                                               
+09 (W):                                                                                                               
+10 (W):                                                                                                               
+11 (W):                                                                                                               
+12 (W):                                                                                                               
+13 (W):                                                                                                               
+14 (W):                                                                                                               
+15 (W):                                                                                                               
+16 (W):                                                                                                               
+17 (W):                                                                                                               
+18 (W):                                                                                                               
+19 (W):                                                                                                               
+20 (W):                                                                                                               
+21 (W):                                                                                                               
+22 (W):                                                                                                               
+23 (W): Origin mode test. This line should be at the bottom of the screen.                                            
+
diff --git a/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_12.snap b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_12.snap
new file mode 100644
index 00000000..fc2bd2de
--- /dev/null
+++ b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_12.snap
@@ -0,0 +1,30 @@
+---
+source: src/client/panes/./unit/grid_tests.rs
+expression: "format!(\"{:?}\", grid)"
+
+---
+00 (W):                    Graphic rendition test pattern:                                                            
+01 (W):                                                                                                               
+02 (W):                                                                                                               
+03 (W): vanilla                                bold                                                                   
+04 (W):                                                                                                               
+05 (W):      underline                              bold underline                                                    
+06 (W):                                                                                                               
+07 (W): blink                                  bold blink                                                             
+08 (W):                                                                                                               
+09 (W):      underline blink                        bold underline blink                                              
+10 (W):                                                                                                               
+11 (W): negative                               bold negative                                                          
+12 (W):                                                                                                               
+13 (W):      underline negative                     bold underline negative                                           
+14 (W):                                                                                                               
+15 (W): blink negative                         bold blink negative                                                    
+16 (W):                                                                                                               
+17 (W):      underline blink negative               bold underline blink negative                                     
+18 (W):                                                                                                               
+19 (W):                                                                                                               
+20 (W):                                                                                                               
+21 (W):                                                                                                               
+22 (W): Dark background. Push <RETURN>                                                                                
+23 (W):                                                                                                               
+
diff --git a/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_13.snap b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_13.snap
new file mode 100644
index 00000000..a79bc0cd
--- /dev/null
+++ b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_13.snap
@@ -0,0 +1,30 @@
+---
+source: src/client/panes/./unit/grid_tests.rs
+expression: "format!(\"{:?}\", grid)"
+
+---
+00 (W):                    Graphic rendition test pattern:                                                            
+01 (W):                                                                                                               
+02 (W):                                                                                                               
+03 (W): vanilla                                bold                                                                   
+04 (W):                                                                                                               
+05 (W):      underline                              bold underline                                                    
+06 (W):                                                                                                               
+07 (W): blink                                  bold blink                                                             
+08 (W):                                                                                                               
+09 (W):      underline blink                        bold underline blink                                              
+10 (W):                                                                                                               
+11 (W): negative                               bold negative                                                          
+12 (W):                                                                                                               
+13 (W):      underline negative                     bold underline negative                                           
+14 (W):                                                                                                               
+15 (W): blink negative                         bold blink negative                                                    
+16 (W):                                                                                                               
+17 (W):      underline blink negative               bold underline blink negative                                     
+18 (W):                                                                                                               
+19 (W):                                                                                                               
+20 (W):                                                                                                               
+21 (W):                                                                                                               
+22 (W): Light background. Push <RETURN>                                                                               
+23 (W):                                                                                                               
+
diff --git a/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_14.snap b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_14.snap
new file mode 100644
index 00000000..dbdc3dc1
--- /dev/null
+++ b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_14.snap
@@ -0,0 +1,30 @@
+---
+source: src/client/panes/./unit/grid_tests.rs
+expression: "format!(\"{:?}\", grid)"
+
+---
+00 (W): AAAAA                                                                                                         
+01 (W): AAAAA                                                                                                         
+02 (W): AAAAA                                                                                                         
+03 (W): AAAAA                                                                                                         
+04 (W):                                                                                                               
+05 (W):                                                                                                               
+06 (W):                                                                                                               
+07 (W):            normal      bold        underscored blinking    reversed                                           
+08 (W):                                                                                                               
+09 (W): stars:     **********  **********  **********  **********  **********                                         
+10 (W):                                                                                                               
+11 (W): line:      ──────────  ──────────  ──────────  ──────────  ──────────                                         
+12 (W):                                                                                                               
+13 (W): x'es:      xxxxxxxxxx  xxxxxxxxxx  xxxxxxxxxx  xxxxxxxxxx  xxxxxxxxxx                                         
+14 (W):                                                                                                               
+15 (W): diamonds:  ◆◆◆◆◆◆◆◆◆◆  ◆◆◆◆◆◆◆◆◆◆  ◆◆◆◆◆◆◆◆◆◆  ◆◆◆◆◆◆◆◆◆◆  ◆◆◆◆◆◆◆◆◆◆                                         
+16 (W):                                                                                                               
+17 (W):                                                                                                               
+18 (W):                                                                                                               
+19 (W):                                                                                                               
+20 (W): Test of the SAVE/RESTORE CURSOR feature. There should                                                         
+21 (W): be ten characters of each flavour, and a rectangle                                                            
+22 (W): of 5 x 4 A's filling the top left of the screen.                                                              
+23 (W): Push <RETURN>                                                                                                 
+
diff --git a/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_2.snap b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_2.snap
new file mode 100644
index 00000000..7b03c147
--- /dev/null
+++ b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_2.snap
@@ -0,0 +1,28 @@
+---
+source: src/client/panes/./unit/grid_tests.rs
+expression: "format!(\"{:?}\", grid)"
+
+---
+00 (C): 12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890
+01 (C): 123456789012345678901                                                                                         
+02 (C):   This is 132 column mode, light background.                                                                  
+03 (C):    This is 132 column mode, light background.                                                                 
+04 (C):     This is 132 column mode, light background.                                                                
+05 (C):      This is 132 column mode, light background.                                                               
+06 (C):       This is 132 column mode, light background.                                                              
+07 (C):        This is 132 column mode, light background.                                                             
+08 (C):         This is 132 column mode, light background.                                                            
+09 (C):          This is 132 column mode, light background.                                                           
+10 (C):           This is 132 column mode, light background.                                                          
+11 (C):            This is 132 column mode, light background.                                                         
+12 (C):             This is 132 column mode, light background.                                                        
+13 (C):              This is 132 column mode, light background.                                                       
+14 (C):               This is 132 column mode, light background.                                                      
+15 (C):                This is 132 column mode, light background.                                                     
+16 (C):                 This is 132 column mode, light background.                                                    
+17 (C):                  This is 132 column mode, light background.                                                   
+18 (C):                   This is 132 column mode, light background.                                                  
+19 (C):                    This is 132 column mode, light background.Push <RETURN>                                    
+20 (C):                                                                                                               
+21 (C):                                                                                                               
+
diff --git a/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_3.snap b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_3.snap
new file mode 100644
index 00000000..98620a5c
--- /dev/null
+++ b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_3.snap
@@ -0,0 +1,28 @@
+---
+source: src/client/panes/./unit/grid_tests.rs
+expression: "format!(\"{:?}\", grid)"
+
+---
+00 (C): 1234567890123456789012345678901234567890123456789012345678901234567890123456789                               
+01 (C):                                                                                                               
+02 (C):   This is 80 column mode, light background.                                                                   
+03 (C):    This is 80 column mode, light background.                                                                  
+04 (C):     This is 80 column mode, light background.                                                                 
+05 (C):      This is 80 column mode, light background.                                                                
+06 (C):       This is 80 column mode, light background.                                                               
+07 (C):        This is 80 column mode, light background.                                                              
+08 (C):         This is 80 column mode, light background.                                                             
+09 (C):          This is 80 column mode, light background.                                                            
+10 (C):           This is 80 column mode, light background.                                                           
+11 (C):            This is 80 column mode, light background.                                                          
+12 (C):             This is 80 column mode, light background.                                                         
+13 (C):              This is 80 column mode, light background.                                                        
+14 (C):               This is 80 column mode, light background.                                                       
+15 (C):                This is 80 column mode, light background.                                                      
+16 (C):                 This is 80 column mode, light background.                                                     
+17 (C):                  This is 80 column mode, light background.                                                    
+18 (C):                   This is 80 column mode, light background.                                                   
+19 (C):                    This is 80 column mode, light background.Push <RETURN>                                     
+20 (C):                                                                                                               
+21 (C):                                                                                                               
+
diff --git a/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_4.snap b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_4.snap
new file mode 100644
index 00000000..35802e63
--- /dev/null
+++ b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_4.snap
@@ -0,0 +1,28 @@
+---
+source: src/client/panes/./unit/grid_tests.rs
+expression: "format!(\"{:?}\", grid)"
+
+---
+00 (C): 12345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890
+01 (C): 123456789012345678901                                                                                         
+02 (C):   This is 132 column mode, dark background.                                                                   
+03 (C):    This is 132 column mode, dark background.                                                                  
+04 (C):     This is 132 column mode, dark background.                                                                 
+05 (C):      This is 132 column mode, dark background.                                                                
+06 (C):       This is 132 column mode, dark background.                                                               
+07 (C):        This is 132 column mode, dark background.                                                              
+08 (C):         This is 132 column mode, dark background.                                                             
+09 (C):          This is 132 column mode, dark background.                                                            
+10 (C):           This is 132 column mode, dark background.                                                           
+11 (C):            This is 132 column mode, dark background.                                                          
+12 (C):             This is 132 column mode, dark background.                                                         
+13 (C):              This is 132 column mode, dark background.                                                        
+14 (C):               This is 132 column mode, dark background.                                                       
+15 (C):                This is 132 column mode, dark background.                                                      
+16 (C):                 This is 132 column mode, dark background.                                                     
+17 (C):                  This is 132 column mode, dark background.                                                    
+18 (C):                   This is 132 column mode, dark background.                                                   
+19 (C):                    This is 132 column mode, dark background.Push <RETURN>                                     
+20 (C):                                                                                                               
+21 (C):                                                                                                               
+
diff --git a/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_5.snap b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_5.snap
new file mode 100644
index 00000000..2bcc2870
--- /dev/null
+++ b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_5.snap
@@ -0,0 +1,28 @@
+---
+source: src/client/panes/./unit/grid_tests.rs
+expression: "format!(\"{:?}\", grid)"
+
+---
+00 (C): 1234567890123456789012345678901234567890123456789012345678901234567890123456789                               
+01 (C):                                                                                                               
+02 (C):   This is 80 column mode, dark background.                                                                    
+03 (C):    This is 80 column mode, dark background.                                                                   
+04 (C):     This is 80 column mode, dark background.                                                                  
+05 (C):      This is 80 column mode, dark background.                                                                 
+06 (C):       This is 80 column mode, dark background.                                                                
+07 (C):        This is 80 column mode, dark background.                                                               
+08 (C):         This is 80 column mode, dark background.                                                              
+09 (C):          This is 80 column mode, dark background.                                                             
+10 (C):           This is 80 column mode, dark background.                                                            
+11 (C):            This is 80 column mode, dark background.                                                           
+12 (C):             This is 80 column mode, dark background.                                                          
+13 (C):              This is 80 column mode, dark background.                                                         
+14 (C):               This is 80 column mode, dark background.                                                        
+15 (C):                This is 80 column mode, dark background.                                                       
+16 (C):                 This is 80 column mode, dark background.                                                      
+17 (C):                  This is 80 column mode, dark background.                                                     
+18 (C):                   This is 80 column mode, dark background.                                                    
+19 (C):                    This is 80 column mode, dark background.Push <RETURN>                                      
+20 (C):                                                                                                               
+21 (C):                                                                                                               
+
diff --git a/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_6.snap b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_6.snap
new file mode 100644
index 00000000..360dc423
--- /dev/null
+++ b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_6.snap
@@ -0,0 +1,28 @@
+---
+source: src/client/panes/./unit/grid_tests.rs
+expression: "format!(\"{:?}\", grid)"
+
+---
+00 (C):                                                                                                               
+01 (C):                                                                                                               
+02 (C):                                                                                                               
+03 (C):                                                                                                               
+04 (C):                                                                                                               
+05 (C):                                                                                                               
+06 (C):                                                                                                               
+07 (C):                                                                                                               
+08 (C):                                                                                                               
+09 (C):                                                                                                               
+10 (C):                                                                                                               
+11 (W): Push <RETURN>
+12 (W): Soft scroll down region [12..13] size 2 Line 29
+13 (C):                                                                                                               
+14 (C):                                                                                                               
+15 (C):                                                                                                               
+16 (C):                                                                                                               
+17 (C):                                                                                                               
+18 (C):                                                                                                               
+19 (C):                                                                                                               
+20 (C):                                                                                                               
+21 (C):                                                                                                               
+
diff --git a/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_7.snap b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_7.snap
new file mode 100644
index 00000000..467ae258
--- /dev/null
+++ b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_7.snap
@@ -0,0 +1,30 @@
+---
+source: src/client/panes/./unit/grid_tests.rs
+expression: "format!(\"{:?}\", grid)"
+
+---
+00 (W): Push <RETURN>
+01 (W): Soft scroll down region [1..24] size 24 Line 29
+02 (W): Soft scroll down region [1..24] size 24 Line 28
+03 (W): Soft scroll down region [1..24] size 24 Line 27
+04 (W): Soft scroll down region [1..24] size 24 Line 26
+05 (W): Soft scroll down region [1..24] size 24 Line 25
+06 (W): Soft scroll down region [1..24] size 24 Line 24
+07 (W): Soft scroll down region [1..24] size 24 Line 23
+08 (W): Soft scroll down region [1..24] size 24 Line 22
+09 (W): Soft scroll down region [1..24] size 24 Line 21
+10 (W): Soft scroll down region [1..24] size 24 Line 20
+11 (W): Soft scroll down region [1..24] size 24 Line 19
+12 (W): Soft scroll down region [1..24] size 24 Line 18
+13 (W): Soft scroll down region [1..24] size 24 Line 17
+14 (W): Soft scroll down region [1..24] size 24 Line 16
+15 (W): Soft scroll down region [1..24] size 24 Line 15
+16 (W): Soft scroll down region [1..24] size 24 Line 14
+17 (W): Soft scroll down region [1..24] size 24 Line 13
+18 (W): Soft scroll down region [1..24] size 24 Line 12
+19 (W): Soft scroll down region [1..24] size 24 Line 11
+20 (W): Soft scroll down region [1..24] size 24 Line 10
+21 (W): Soft scroll down region [1..24] size 24 Line 9
+22 (W): Soft scroll down region [1..24] size 24 Line 8
+23 (W): Soft scroll down region [1..24] size 24 Line 7
+
diff --git a/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_8.snap b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_8.snap
new file mode 100644
index 00000000..f892edd2
--- /dev/null
+++ b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_8.snap
@@ -0,0 +1,30 @@
+---
+source: src/client/panes/./unit/grid_tests.rs
+expression: "format!(\"{:?}\", grid)"
+
+---
+00 (W):                                                                                                               
+01 (W):                                                                                                               
+02 (W):                                                                                                               
+03 (W):                                                                                                               
+04 (W):                                                                                                               
+05 (W):                                                                                                               
+06 (W):                                                                                                               
+07 (W):                                                                                                               
+08 (W):                                                                                                               
+09 (W):                                                                                                               
+10 (W):                                                                                                               
+11 (W): Push <RETURN>
+12 (W): Jump scroll down region [12..13] size 2 Line 29
+13 (W):                                                                                                               
+14 (W):                                                                                                               
+15 (W):                                                                                                               
+16 (W):                                                                                                               
+17 (W):                                                                                                               
+18 (W):                                                                                                               
+19 (W):                                                                                                               
+20 (W):                                                                                                               
+21 (W):                                                                                                               
+22 (W):                                                                                                               
+23 (W):                                                                                                               
+
diff --git a/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_9.snap b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_9.snap
new file mode 100644
index 00000000..63e46c04
--- /dev/null
+++ b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest2_9.snap
@@ -0,0 +1,30 @@
+---
+source: src/client/panes/./unit/grid_tests.rs
+expression: "format!(\"{:?}\", grid)"
+
+---
+00 (W): Push <RETURN>
+01 (W): Jump scroll down region [1..24] size 24 Line 29
+02 (W): Jump scroll down region [1..24] size 24 Line 28
+03 (W): Jump scroll down region [1..24] size 24 Line 27
+04 (W): Jump scroll down region [1..24] size 24 Line 26
+05 (W): Jump scroll down region [1..24] size 24 Line 25
+06 (W): Jump scroll down region [1..24] size 24 Line 24
+07 (W): Jump scroll down region [1..24] size 24 Line 23
+08 (W): Jump scroll down region [1..24] size 24 Line 22
+09 (W): Jump scroll down region [1..24] size 24 Line 21
+10 (W): Jump scroll down region [1..24] size 24 Line 20
+11 (W): Jump scroll down region [1..24] size 24 Line 19
+12 (W): Jump scroll down region [1..24] size 24 Line 18
+13 (W): Jump scroll down region [1..24] size 24 Line 17
+14 (W): Jump scroll down region [1..24] size 24 Line 16
+15 (W): Jump scroll down region [1..24] size 24 Line 15
+16 (W): Jump scroll down region [1..24] size 24 Line 14
+17 (W): Jump scroll down region [1..24] size 24 Line 13
+18 (W): Jump scroll down region [1..24] size 24 Line 12
+19 (W): Jump scroll down region [1..24] size 24 Line 11
+20 (W): Jump scroll down region [1..24] size 24 Line 10
+21 (W): Jump scroll down region [1..24] size 24 Line 9
+22 (W): Jump scroll down region [1..24] size 24 Line 8
+23 (W): Jump scroll down region [1..24] size 24 Line 7
+
diff --git a/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest3_0.snap b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest3_0.snap
new file mode 100644
index 00000000..42c6f634
--- /dev/null
+++ b/src/client/panes/unit/snapshots/zellij__client__panes__grid__grid_tests__vttest3_0.snap
@@ -0,0 +1,30 @@
+---
+source: src/client/panes/./unit/grid_tests.rs
+expression: "format!(\"{:?}\", grid)"
+
+---
+00 (C):          Selected as G0 (with SI)              Selected as G1 (with SO)                                       
+01 (C):                                                                                                               
+02 (C): Character set B (US ASCII)                                                                                    
+03 (C):           !"#$%&'()*+,-./0123456789:;<=>?       !"#$%&'()*+,-./0123456789:;<=>?                               
+04 (C):          @ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_      @ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_                               
+05 (C):          `abcdefghijklmnopqrstuvwxyz{|}~      `abcdefghijklmnopqrstuvwxyz{|}~                               
+06 (C): Character set A (British)                                                                                     
+07 (C):           !"#$%&'()*+,-./0123456789:;<=>?       !"#$%&'()*+,-./0123456789:;<=>?                               
+08 (C):          @ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_      @ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_                               
+09 (C):          `abcdefghijklmnopqrstuvwxyz{|}~      `abcdefghijklmnopqrstuvwxyz{|}~                               
+10 (C): Character set 0 (DEC Special graphics and line drawing)                                                       
+11 (C):           !"#$%&'()*+,-./0123456789:;<=>?       !"#$%&'()*+,-./0123456789:;<=>?                               
+12 (C):          @ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_      @ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_                               
+13 (C):          ◆▒␉␌␍␊°±␤␋┘┐┌└┼⎺⎻─⎼⎽├┤┴┬│≤≥π≠£·      ◆▒␉␌␍␊°±␤␋┘┐┌└┼⎺⎻─⎼⎽├┤┴┬│≤≥π≠£·                               
+14 (C): Character set 1 (DEC Alternate character ROM standard characters)                                             
+15 (C):           !"#$%&'()*+,-./0123456789:;<=>?       !"#$%&'()*+,-./0123456789:;<=>?                               
+16 (C):          @ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_      @ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_                               
+17 (C):          `abcdefghijklmnopqrstuvwxyz{|}~      `abcdefghijklmnopqrstuvwxyz{|}~                               
+18 (C): Character set 2 (DEC Alternate character ROM special graphics)                                                
+19 (C):           !"#$%&'()*+,-./0123456789:;<=>?       !"#$%&'()*+,-./0123456789:;<=>?                               
+20 (C):          @ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_      @ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_                               
+21 (C):          `abcdefghijklmnopqrstuvwxyz{|}~      `abcdefghijklmnopqrstuvwxyz{|}~                               
+22 (C):                                                                                                               
+23 (C): These are the installed character sets. Push <RETURN>                                                         
+