feat: add configurable whitespace markers

TODO.md

@@ -1,5 +1,5 @@
 - [x] add option to highlight trailing whitespace (off by default)
-- [ ] add option to put characters at certain whitespace characters (off by default)
+- [x] add option to put characters at certain whitespace characters (off by default)
 	- whitespace kind -> character map should be configurable.
 - [ ] github/gitlab/gitea integration (probably requries authentication with github)
 	- github pr picker (floating window)

docs/configuration.md

@@ -17,6 +17,7 @@ Vamp.configure do |config|
   config.git_gutter = "bar" # or "symbols", "line_numbers", "none"
   config.scroll_distance = 0 # nonnegative edge distance, or nil to center
   config.highlight_trailing_whitespace = false # true marks line-end whitespace in red
+  config.whitespace_characters = {} # opt in: { " " => "·", "\t" => "→", "\u00a0" => "⍽" }
   config.file_explorer_side = "right"
   config.file_explorer_view = "tree"
   config.file_picker_view = "tree"
@@ -55,6 +56,10 @@ The setting applies to ordinary and historical buffers, split/unified diff panes
 
 `config.highlight_trailing_whitespace` defaults to `false`. Set it to `true` to give trailing whitespace a red background in ordinary and historical buffers and both sides of split/unified diffs, including wrapped and horizontally scrolled text. Spaces, expanded tab cells, and Unicode whitespace at the end of a source line are highlighted; whitespace-only lines are included, but empty lines and padding beyond the text are not. Wrapping does not make interior whitespace trailing. Search, selections, and secondary carets retain their background precedence; diagnostic underlines remain visible. This changes display only, not file contents. Only literal Ruby booleans are accepted; other values reject the configuration.
 
+`config.whitespace_characters` defaults to `{}` (disabled). Assign a hash mapping literal whitespace characters to display markers, for example `{ " " => "·", "\t" => "→", "\u00a0" => "⍽" }` for spaces, tabs, and nonbreaking spaces. Unlisted characters keep their ordinary appearance. Keys and values must be single-character strings; keys must be whitespace with visible terminal width, or tabs, and values must be printable one-cell characters. Line breaks and other control characters, zero-width markers, and wide markers reject the configuration.
+
+Markers appear in ordinary and historical buffers and both sides of split/unified diffs. Tabs and wide Unicode whitespace show the marker in their first source cell and leave remaining cells blank, preserving tab stops, wrapping, horizontal scrolling, and cursor/selection geometry. A clipped first cell hides its marker; empty lines and padding do not gain markers. Whitespace with combining characters remains intact. Syntax colors, search, selections, diagnostics, and trailing-whitespace highlighting still apply. This changes display only: editing, copying, and saving retain the original characters.
+
 `config.git_blame` defaults to `true`; set it to `false` to disable current-line inline Git blame and its background worker. Only literal Ruby booleans are accepted; other values reject the configuration. Toggle it for the running session with `:git_blame.toggle`, its palette action, or a custom binding such as `config.bind "leader b", config.core.git_blame.toggle`. There is no default shortcut.
 
 `config.git_gutter` defaults to `"bar"`: a fat `▌` with one blank column between the line number and marker and another before the text. `"symbols"` uses `+` / `-` / `~` with the same spacing. Added, removed, and modified lines use green, red, and yellow respectively. `"line_numbers"` colors the existing numbers without adding a marker column; the current line retains its cyan/bold caret highlight. `"none"` hides line-gutter repository indicators, not line numbers or picker file statuses. Other modes retain diagnostic number colors independently of repository markers. Unsupported strings, empty strings, and non-string values reject the configuration.

examples/config.rb

@@ -7,6 +7,7 @@ Vamp.configure do |config|
   config.git_blame = true # false disables current-line inline blame
   config.scroll_distance = 0 # nonnegative edge distance, or nil to center
   config.highlight_trailing_whitespace = false # true marks line-end whitespace in red
+  config.whitespace_characters = {} # opt in: { " " => "·", "\t" => "→", "\u00a0" => "⍽" }
   config.file_explorer_side = "right"
   config.file_explorer_view = "tree"
   config.file_picker_view = "tree"

src/editor.rs

@@ -1764,6 +1764,7 @@ pub struct Editor {
     labels: BTreeMap<String, String>,
     scroll_distance: Option<usize>,
     highlight_trailing_whitespace: bool,
+    whitespace_characters: BTreeMap<char, char>,
     battery_charge: Option<u8>,
     battery_label: String,
     git_blame: bool,
@@ -1867,6 +1868,7 @@ impl Editor {
             labels: BTreeMap::new(),
             scroll_distance: Some(0),
             highlight_trailing_whitespace: false,
+            whitespace_characters: BTreeMap::new(),
             battery_charge: None,
             battery_label: String::new(),
             git_blame: true,
@@ -2621,6 +2623,14 @@ impl Editor {
         self.highlight_trailing_whitespace = enabled;
     }
 
+    pub(crate) fn whitespace_characters(&self) -> &BTreeMap<char, char> {
+        &self.whitespace_characters
+    }
+
+    pub(crate) fn set_whitespace_characters(&mut self, characters: BTreeMap<char, char>) {
+        self.whitespace_characters = characters;
+    }
+
     pub(crate) fn set_diff_context_options(&mut self, context_lines: usize, expand_lines: usize) {
         self.diff_context_options = (context_lines, expand_lines);
         if let Some(diff) = &mut self.diff {

src/ruby.rs

@@ -46,6 +46,7 @@ pub struct Config {
     pub labels: BTreeMap<String, String>,
     pub scroll_distance: Option<usize>,
     pub highlight_trailing_whitespace: bool,
+    pub whitespace_characters: BTreeMap<char, char>,
     pub diff_context_lines: usize,
     pub diff_expand_lines: usize,
     pub diff_view_mode: crate::diff::ViewMode,
@@ -93,6 +94,7 @@ impl Default for Config {
             labels: BTreeMap::new(),
             scroll_distance: Some(0),
             highlight_trailing_whitespace: false,
+            whitespace_characters: BTreeMap::new(),
             diff_context_lines: 10,
             diff_expand_lines: 15,
             diff_view_mode: crate::diff::ViewMode::Split,
@@ -127,6 +129,7 @@ pub fn load_config(path: &Path) -> Result<Config, String> {
                 labels,
                 scroll_distance,
                 highlight_trailing_whitespace,
+                whitespace_characters,
                 diff_context_lines,
                 diff_expand_lines,
                 diff_view_mode,
@@ -162,6 +165,7 @@ pub fn load_config(path: &Path) -> Result<Config, String> {
             config.labels = labels;
             config.scroll_distance = scroll_distance;
             config.highlight_trailing_whitespace = highlight_trailing_whitespace;
+            config.whitespace_characters = whitespace_characters;
             config.diff_context_lines = diff_context_lines;
             config.diff_expand_lines = diff_expand_lines;
             config.diff_view_mode = diff_view_mode;
@@ -496,6 +500,8 @@ struct ConfigFrame {
     #[serde(deserialize_with = "scroll_distance")]
     scroll_distance: Option<usize>,
     highlight_trailing_whitespace: bool,
+    #[serde(deserialize_with = "whitespace_characters")]
+    whitespace_characters: BTreeMap<char, char>,
     #[serde(deserialize_with = "diff_context_lines")]
     diff_context_lines: usize,
     #[serde(deserialize_with = "diff_expand_lines")]
@@ -505,6 +511,30 @@ struct ConfigFrame {
     diff_follow_working_copy: bool,
 }
 
+fn whitespace_characters<'de, D: serde::Deserializer<'de>>(
+    deserializer: D,
+) -> Result<BTreeMap<char, char>, D::Error> {
+    use unicode_width::UnicodeWidthChar;
+
+    let characters = BTreeMap::<char, char>::deserialize(deserializer)?;
+    for (&whitespace, &marker) in &characters {
+        if !whitespace.is_whitespace()
+            || (whitespace != '\t'
+                && (whitespace.is_control() || whitespace.width().unwrap_or(0) == 0))
+        {
+            return Err(serde::de::Error::custom(
+                "whitespace_characters keys must be visible-width whitespace characters or tabs",
+            ));
+        }
+        if marker.is_control() || marker.width() != Some(1) {
+            return Err(serde::de::Error::custom(
+                "whitespace_characters values must be printable single-cell characters",
+            ));
+        }
+    }
+    Ok(characters)
+}
+
 #[derive(Deserialize)]
 #[serde(tag = "type", deny_unknown_fields)]
 enum Response {
@@ -1239,9 +1269,9 @@ end
             assert!(load_config(&path).unwrap_err().contains(error), "{value}");
         }
         for frame in [
-            r#"{"type":"config","version":1,"plugins":[],"lsp":{},"bindings":[],"file_explorer_side":"right","file_picker_view":"list","file_explorer_view":"tree","clipboard_mode":"system","git_blame":true,"git_gutter":"bar","scroll_distance":0,"highlight_trailing_whitespace":false,"top_bar":{},"bottom_bar":{},"popup":{"command":{},"search":{}},"labels":{},"diff_context_lines":10,"diff_expand_lines":15,"diff_view_mode":"split","diff_split_orientation":"vertical","diff_follow_working_copy":true}"#,
+            r#"{"type":"config","version":1,"plugins":[],"lsp":{},"bindings":[],"file_explorer_side":"right","file_picker_view":"list","file_explorer_view":"tree","clipboard_mode":"system","git_blame":true,"git_gutter":"bar","scroll_distance":0,"highlight_trailing_whitespace":false,"whitespace_characters":{},"top_bar":{},"bottom_bar":{},"popup":{"command":{},"search":{}},"labels":{},"diff_context_lines":10,"diff_expand_lines":15,"diff_view_mode":"split","diff_split_orientation":"vertical","diff_follow_working_copy":true}"#,
-            r#"{"type":"config","version":1,"plugins":[],"lsp":{},"bindings":[],"leader":null,"file_explorer_side":"right","file_picker_view":"list","file_explorer_view":"tree","clipboard_mode":"system","git_blame":true,"git_gutter":"bar","scroll_distance":0,"highlight_trailing_whitespace":false,"top_bar":{},"bottom_bar":{},"popup":{"command":{},"search":{}},"labels":{},"diff_context_lines":10,"diff_expand_lines":15,"diff_view_mode":"split","diff_split_orientation":"vertical","diff_follow_working_copy":true}"#,
+            r#"{"type":"config","version":1,"plugins":[],"lsp":{},"bindings":[],"leader":null,"file_explorer_side":"right","file_picker_view":"list","file_explorer_view":"tree","clipboard_mode":"system","git_blame":true,"git_gutter":"bar","scroll_distance":0,"highlight_trailing_whitespace":false,"whitespace_characters":{},"top_bar":{},"bottom_bar":{},"popup":{"command":{},"search":{}},"labels":{},"diff_context_lines":10,"diff_expand_lines":15,"diff_view_mode":"split","diff_split_orientation":"vertical","diff_follow_working_copy":true}"#,
-            r#"{"type":"config","version":1,"plugins":[],"lsp":{},"bindings":[],"leader":7,"file_explorer_side":"right","file_picker_view":"list","file_explorer_view":"tree","clipboard_mode":"system","git_blame":true,"git_gutter":"bar","scroll_distance":0,"highlight_trailing_whitespace":false,"top_bar":{},"bottom_bar":{},"popup":{"command":{},"search":{}},"labels":{},"diff_context_lines":10,"diff_expand_lines":15,"diff_view_mode":"split","diff_split_orientation":"vertical","diff_follow_working_copy":true}"#,
+            r#"{"type":"config","version":1,"plugins":[],"lsp":{},"bindings":[],"leader":7,"file_explorer_side":"right","file_picker_view":"list","file_explorer_view":"tree","clipboard_mode":"system","git_blame":true,"git_gutter":"bar","scroll_distance":0,"highlight_trailing_whitespace":false,"whitespace_characters":{},"top_bar":{},"bottom_bar":{},"popup":{"command":{},"search":{}},"labels":{},"diff_context_lines":10,"diff_expand_lines":15,"diff_view_mode":"split","diff_split_orientation":"vertical","diff_follow_working_copy":true}"#,
         ] {
             assert!(serde_json::from_str::<Response>(frame).is_err(), "{frame}");
         }
@@ -1319,6 +1349,7 @@ end
             "git_gutter": "bar",
             "scroll_distance": 0,
             "highlight_trailing_whitespace": false,
+            "whitespace_characters": {},
             "top_bar": {}, "bottom_bar": {}, "popup": {"command": {}, "search": {}},
             "labels": {}, "diff_context_lines": 10, "diff_expand_lines": 15,
             "diff_view_mode": "split", "diff_split_orientation": "vertical",
@@ -1353,6 +1384,42 @@ end
         }
     }
 
+    #[test]
+    fn whitespace_characters_validate_real_ruby_configuration() {
+        let fixture = Fixture::new();
+        for value in [
+            "nil",
+            "false",
+            "[]",
+            r#"{ space: "·" }"#,
+            r#"{ " " => 1 }"#,
+            r#"{ "" => "." }"#,
+            r#"{ "  " => "." }"#,
+            r#"{ " " => ".." }"#,
+            r#"{ "x" => "." }"#,
+            r#"{ "\n" => "." }"#,
+            r#"{ "\r" => "." }"#,
+            r#"{ "\u200b" => "." }"#,
+            r#"{ " " => "\t" }"#,
+            r#"{ " " => "\u0301" }"#,
+            r#"{ " " => "界" }"#,
+        ] {
+            let path = fixture.file(
+                "config.rb",
+                &format!("Vamp.configure {{ |c| c.whitespace_characters = {value} }}"),
+            );
+            assert!(load_config(&path).is_err(), "{value}");
+        }
+        let path = fixture.file(
+            "config.rb",
+            r#"Vamp.configure { |c| c.whitespace_characters = { " " => "·", "\t" => "→", "\u00a0" => "⍽", "\u3000" => "_" } }"#,
+        );
+        assert_eq!(
+            load_config(&path).unwrap().whitespace_characters,
+            BTreeMap::from([(' ', '·'), ('\t', '→'), ('\u{a0}', '⍽'), ('\u{3000}', '_')]),
+        );
+    }
+
     #[test]
     fn working_diff_tracking_rejects_non_boolean_configuration() {
         let fixture = Fixture::new();
@@ -1587,6 +1654,7 @@ end
             "top_bar": {}, "bottom_bar": {}, "labels": {},
             "scroll_distance": 0,
             "highlight_trailing_whitespace": false,
+            "whitespace_characters": {},
             "popup": {"command": {}, "search": {}},
             "clipboard_mode": "system", "diff_context_lines": 0, "diff_expand_lines": 7,
             "diff_view_mode": "split", "diff_split_orientation": "vertical",
@@ -1636,6 +1704,7 @@ end
             "file_picker_view": "tree", "file_explorer_view": "tree",
             "clipboard_mode": "system", "git_blame": true, "git_gutter": "bar",
             "highlight_trailing_whitespace": false,
+            "whitespace_characters": {},
             "top_bar": {}, "bottom_bar": {}, "labels": {},
             "popup": {"command": {}, "search": {}},
             "diff_context_lines": 10, "diff_expand_lines": 15,
@@ -2065,6 +2134,7 @@ end"#,
             "git_gutter": "bar",
             "scroll_distance": 0,
             "highlight_trailing_whitespace": false,
+            "whitespace_characters": {},
             "top_bar": {}, "bottom_bar": {}, "labels": {},
             "popup": {"command": {}, "search": {}},
             "clipboard_mode": "system", "diff_context_lines": 10, "diff_expand_lines": 15,

src/ruby_config.rb

@@ -143,6 +143,7 @@ module Vamp
       @labels = {}
       @scroll_distance = 0
       @highlight_trailing_whitespace = false
+      @whitespace_characters = {}
       @diff_context_lines = 10
       @diff_expand_lines = 15
       @diff_view_mode = "split"
@@ -230,6 +231,19 @@ module Vamp
       @highlight_trailing_whitespace = enabled
     end
 
+    # @param characters [Hash{String => String}] whitespace character to single-cell marker
+    # @return [Hash{String => String}]
+    def whitespace_characters=(characters)
+      raise TypeError, "whitespace_characters must be a Hash" unless characters.is_a?(Hash)
+
+      characters.each do |whitespace, marker|
+        unless [whitespace, marker].all? { |value| value.is_a?(String) && value.length == 1 }
+          raise TypeError, "whitespace_characters keys and values must be single-character Strings"
+        end
+      end
+      @whitespace_characters = characters.dup
+    end
+
     # @param lines [Integer] nonnegative context lines around each diff change
     # @return [Integer]
     def diff_context_lines=(lines)
@@ -303,6 +317,7 @@ module Vamp
         "git_gutter" => @git_gutter,
         "scroll_distance" => @scroll_distance,
         "highlight_trailing_whitespace" => @highlight_trailing_whitespace,
+        "whitespace_characters" => @whitespace_characters,
         "top_bar" => @bar.top, "bottom_bar" => @bar.bottom, "labels" => @labels,
         "popup" => { "command" => @popup.command, "search" => @popup.search },
         "diff_context_lines" => @diff_context_lines, "diff_expand_lines" => @diff_expand_lines,

src/session.rs

@@ -258,6 +258,7 @@ impl EditorSession {
         editor.set_gutter_style(config.git_gutter);
         editor.set_scroll_distance(config.scroll_distance);
         editor.set_highlight_trailing_whitespace(config.highlight_trailing_whitespace);
+        editor.set_whitespace_characters(config.whitespace_characters);
         editor.set_diff_context_options(config.diff_context_lines, config.diff_expand_lines);
         editor.set_diff_display_options(config.diff_view_mode, config.diff_split_orientation);
         if let Err(error) =

src/tui.rs

@@ -995,6 +995,15 @@ fn display_column(line: &str, grapheme_column: usize) -> usize {
 }
 
 fn visible_line(line: &str, left: usize, width: usize) -> String {
+    visible_text(line, left, width, None)
+}
+
+fn visible_text(
+    line: &str,
+    left: usize,
+    width: usize,
+    whitespace: Option<&BTreeMap<char, char>>,
+) -> String {
     let mut visible = String::new();
     let mut column = 0;
     let right = left.saturating_add(width);
@@ -1009,6 +1018,19 @@ fn visible_line(line: &str, left: usize, width: usize) -> String {
             break;
         }
         if end > left || (cells == 0 && column >= left) {
+            let marker = whitespace.and_then(|characters| {
+                let ch = grapheme.chars().next()?;
+                (grapheme.len() == ch.len_utf8())
+                    .then(|| characters.get(&ch))
+                    .flatten()
+            });
+            if let Some(&marker) = marker {
+                for cell in column.max(left)..end.min(right) {
+                    visible.push(if cell == column { marker } else { ' ' });
+                }
+                column = end;
+                continue;
+            }
             if grapheme == "\t" || column < left || end > right {
                 for _ in column.max(left)..end.min(right) {
                     visible.push(' ');
@@ -1834,10 +1856,11 @@ fn draw_document(
             .visible
             .iter()
             .map(|&(row, _, segment)| {
-                Line::from(visible_line(
+                Line::from(visible_text(
                     &editor.lines()[row],
                     segment.start,
                     segment.end.saturating_sub(segment.start).min(width),
+                    Some(editor.whitespace_characters()),
                 ))
             })
             .collect();
@@ -2938,6 +2961,7 @@ fn draw_diff(
                     wrapped,
                     panels.diff_colors,
                     editor.is_some_and(Editor::highlight_trailing_whitespace),
+                    editor.map(Editor::whitespace_characters),
                 );
                 text_widths[0] = text_area.width;
                 if let Some(editor) =
@@ -2975,6 +2999,7 @@ fn draw_diff(
                     wrapped,
                     panels.diff_colors,
                     editor.is_some_and(Editor::highlight_trailing_whitespace),
+                    editor.map(Editor::whitespace_characters),
                 );
                 text_widths[1] = text_area.width;
                 if let Some(editor) =
@@ -3130,6 +3155,7 @@ fn draw_diff_pane(
     wrapped: Option<&[WrappedDiffRow]>,
     colors: DiffColors,
     highlight_trailing_whitespace: bool,
+    whitespace_characters: Option<&BTreeMap<char, char>>,
 ) -> Rect {
     if area.width == 0 || area.height == 0 {
         return area;
@@ -3237,8 +3263,13 @@ fn draw_diff_pane(
             Cow::Borrowed(source_text.as_str())
         };
         frame.render_widget(
-            Paragraph::new(visible_line(&text, left, text_width.min(width)))
+            Paragraph::new(visible_text(
-                .style(Style::default().fg(Color::Reset).bg(background)),
+                &text,
+                left,
+                text_width.min(width),
+                whitespace_characters,
+            ))
+            .style(Style::default().fg(Color::Reset).bg(background)),
             Rect::new(content.x + gutter as u16, row_area.y, width as u16, 1),
         );
         if gutter > 0 && wrapped.is_none_or(|rows| rows[screen].position.continuation == 0) {
@@ -4883,6 +4914,73 @@ mod tests {
         }
     }
 
+    #[test]
+    fn whitespace_characters_preserve_source_geometry_and_overlay_styles() {
+        let characters =
+            BTreeMap::from([(' ', '·'), ('\t', '→'), ('\u{a0}', '⍽'), ('\u{3000}', '_')]);
+        let source = "a \tb\u{a0}\u{3000} c";
+        assert_eq!(visible_text(source, 0, 20, Some(&characters)), "a·→ b⍽_ ·c");
+        assert_eq!(visible_text(source, 3, 6, Some(&characters)), " b⍽_ ·");
+        assert_eq!(visible_text(source, 7, 2, Some(&characters)), " ·");
+        assert_eq!(visible_text(source, 6, 1, Some(&characters)), "_");
+        assert_eq!(
+            visible_text(" \u{301}", 0, 4, Some(&characters)),
+            " \u{301}"
+        );
+        assert_eq!(visible_text("", 0, 4, Some(&characters)), "");
+
+        let directory = Directory::new();
+        let source = "a b\t \u{3000}\n \t\n\nabcdefg  ";
+        let path = directory.file("markers.txt", source);
+        let config = directory.file(
+            "config.rb",
+            r#"Vamp.configure { |c| c.whitespace_characters = { " " => "·", "\t" => "→", "\u3000" => "_" }; c.highlight_trailing_whitespace = true; c.git_gutter = "none" }"#,
+        );
+        let mut session = EditorSession::open(Some(path.clone()), vec![], Some(&config)).unwrap();
+        session.execute("word_wrap.toggle");
+        let mut terminal = Terminal::new(ratatui::backend::TestBackend::new(10, 10)).unwrap();
+        let mut views = BufferViewports::default();
+        terminal
+            .draw(|frame| views.draw(frame, session.editor_mut()))
+            .unwrap();
+        let buffer = terminal.backend().buffer();
+        for (x, y, marker) in [
+            (3, 0, "·"),
+            (5, 0, "→"),
+            (6, 0, "·"),
+            (7, 0, "_"),
+            (2, 1, "·"),
+            (3, 1, "→"),
+            (9, 3, "·"),
+            (2, 4, "·"),
+        ] {
+            assert_eq!(buffer[(x, y)].symbol(), marker, "({x}, {y})");
+        }
+        assert_eq!(buffer[(8, 0)].symbol(), " ");
+        assert_eq!(buffer[(7, 0)].bg, Color::Red);
+        assert_eq!(buffer[(2, 2)].symbol(), " ");
+        session.handle(Input::End);
+        session.handle(Input::Char('v'));
+        session.handle(Input::Left);
+        terminal
+            .draw(|frame| views.draw(frame, session.editor_mut()))
+            .unwrap();
+        assert_eq!(terminal.backend().buffer()[(6, 0)].symbol(), "·");
+        assert_eq!(terminal.backend().buffer()[(6, 0)].bg, Color::Blue);
+        assert_eq!(session.editor().lines().join("\n"), source);
+        assert!(!session.editor().dirty());
+        assert_eq!(fs::read_to_string(path).unwrap(), source);
+
+        session
+            .editor_mut()
+            .set_whitespace_characters(BTreeMap::new());
+        terminal
+            .draw(|frame| views.draw(frame, session.editor_mut()))
+            .unwrap();
+        assert_eq!(terminal.backend().buffer()[(6, 0)].symbol(), " ");
+        assert_eq!(terminal.backend().buffer()[(7, 0)].symbol(), "\u{3000}");
+    }
+
     #[test]
     fn trailing_whitespace_is_opt_in_and_preserves_wrapping_and_selection() {
         let directory = Directory::new();
@@ -4945,6 +5043,7 @@ mod tests {
                     syntax_diff_file("whitespace.txt", "old \t", "new \t"),
                 );
                 editor.set_highlight_trailing_whitespace(true);
+                editor.set_whitespace_characters(BTreeMap::from([(' ', '·'), ('\t', '→')]));
                 if wrapped {
                     editor.execute("word_wrap.toggle");
                 }
@@ -4979,6 +5078,8 @@ mod tests {
                         );
                     }
                     assert_ne!(buffer.content[start + 8].bg, Color::Red);
+                    assert_eq!(buffer.content[start + 3].symbol(), "·");
+                    assert_eq!(buffer.content[start + 4].symbol(), "→");
                 }
             }
         }