documents: lists go on, block lines shift, tables change, matches show, fences color by language

The document carries Markdown's editing tools for ElyMark (MARK-06):
Enter continues a list item or ends an empty one, Tab and Shift-Tab
shift an open block's lines, table rows and columns come and go as
one undo step, a match shows in any mode, replacements are one step,
and a fenced block colors by its language.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/documents/document/tests/mod.rs

@@ -368,6 +368,7 @@ fn a_press_after_a_write_back_waits_for_the_long_read(cx: &mut TestAppContext) {
 mod history;
 mod links;
 mod place;
+mod tools;
 
 #[gpui::test]
 fn typed_source_reads_after_a_pause(cx: &mut TestAppContext) {

src/documents/document/tests/tools.rs

@@ -0,0 +1,95 @@
+use gpui::{Modifiers, TestAppContext};
+
+use super::{MarkdownMode, open, opened, press, text};
+
+#[gpui::test]
+fn enter_in_source_goes_on_with_the_list(cx: &mut TestAppContext) {
+    let (document, cx) = open("- a", MarkdownMode::Source, cx);
+    document.update(cx, |document, cx| document.set_caret(0, 3, cx));
+    let editor = document.read_with(cx, |document, _| document.editor().clone());
+    let focus = editor.read_with(cx, gpui::Focusable::focus_handle);
+    cx.update(|window, cx| window.focus(&focus, cx));
+    cx.simulate_keystrokes("enter");
+    cx.simulate_input("b");
+    assert_eq!(text(&document, cx), "- a\n- b");
+    cx.simulate_keystrokes("enter enter");
+    assert_eq!(
+        text(&document, cx),
+        "- a\n- b\n",
+        "an empty item ends the list"
+    );
+}
+
+#[gpui::test]
+fn enter_in_a_block_goes_on_with_the_list(cx: &mut TestAppContext) {
+    let (document, cx) = open("1. a\n", MarkdownMode::Visual, cx);
+    press(0, Modifiers::none(), cx);
+    cx.simulate_keystrokes("enter");
+    cx.simulate_input("b");
+    assert_eq!(opened(&document, cx), "1. a\n2. b");
+}
+
+#[gpui::test]
+fn tab_shifts_a_block_line_in_and_out(cx: &mut TestAppContext) {
+    let (document, cx) = open("- a\n- b\n", MarkdownMode::Visual, cx);
+    press(0, Modifiers::none(), cx);
+    cx.simulate_keystrokes("tab");
+    assert_eq!(opened(&document, cx), "- a\n    - b");
+    cx.simulate_keystrokes("shift-tab");
+    assert_eq!(opened(&document, cx), "- a\n- b");
+}
+
+#[gpui::test]
+fn a_table_edit_is_one_undo_step_at_the_caret(cx: &mut TestAppContext) {
+    let (document, cx) = open("| A |\n| - |\n| 1 |\n", MarkdownMode::Source, cx);
+    document.update(cx, |document, cx| document.set_caret(2, 2, cx));
+    let edited = document.update(cx, |document, cx| {
+        document.edit_table(crate::documents::TableEdit::RowBelow, cx)
+    });
+    assert!(edited);
+    assert_eq!(text(&document, cx), "| A |\n| --- |\n| 1 |\n|  |\n");
+    let editor = document.read_with(cx, |document, _| document.editor().clone());
+    editor.update(cx, |editor, cx| editor.undo(cx));
+    assert_eq!(text(&document, cx), "| A |\n| - |\n| 1 |\n");
+}
+
+#[gpui::test]
+fn a_new_table_goes_after_the_caret_line(cx: &mut TestAppContext) {
+    let (document, cx) = open("Intro\nNext\n", MarkdownMode::Visual, cx);
+    document.update(cx, |document, cx| document.insert_table(cx));
+    assert_eq!(
+        text(&document, cx),
+        "Intro\n\n|   |   |   |\n| --- | --- | --- |\n|   |   |   |\n|   |   |   |\n\nNext\n"
+    );
+}
+
+#[gpui::test]
+fn a_match_in_visual_opens_its_block_selected(cx: &mut TestAppContext) {
+    let (document, cx) = open("# A\n\nfind me here\n", MarkdownMode::Visual, cx);
+    let at = "# A\n\nfind me here\n".find("me").expect("the word");
+    document.update_in(cx, |document, window, cx| {
+        document.show_match(at..at + 2, window, cx)
+    });
+    let selected = document.read_with(cx, |document, cx| {
+        let input = document
+            .open
+            .as_ref()
+            .expect("a block opens")
+            .input
+            .read(cx);
+        input.text()[input.selection()].to_string()
+    });
+    assert_eq!(selected, "me");
+}
+
+#[gpui::test]
+fn every_replacement_is_one_undo_step(cx: &mut TestAppContext) {
+    let (document, cx) = open("a b a", MarkdownMode::Visual, cx);
+    document.update(cx, |document, cx| {
+        document.replace(vec![(0..1, "x".into()), (4..5, "x".into())], cx)
+    });
+    assert_eq!(text(&document, cx), "x b x");
+    let editor = document.read_with(cx, |document, _| document.editor().clone());
+    editor.update(cx, |editor, cx| editor.undo(cx));
+    assert_eq!(text(&document, cx), "a b a");
+}