test(text): preserve duplicate glyph occurrence order (#6323)

crates/text/src/tests/harakat.rs

@@ -512,6 +512,43 @@ fn assert_authored_ownership(t: &TextObject, text: &str, l: &TextLayout, what: &
     }
 }
 
+/// Repeated glyphs in one cluster can belong to differently painted runs. Match each authored
+/// occurrence in order, without needing an installed font, and still reject a changed owner.
+#[test]
+fn duplicate_authored_glyphs_keep_occurrence_order() {
+    let mut text = TextObject::point(Point::ZERO, "\u{0651}", style(FAMILY));
+    text.runs.push(vectorcraft_doc::TextRun::new("\u{0651}", CharStyle { fill: red(), ..style(FAMILY) }));
+    let glyph = |run| PositionedGlyph {
+        outline: Default::default(),
+        run,
+        byte: 0,
+        origin: Point::ZERO,
+        advance: 0.0,
+        len: 4,
+        angle: 0.0,
+        line: 0,
+        font_id: 0,
+        gid: 7,
+        xf: Affine::IDENTITY,
+        rtl: true,
+        scale: 1.0,
+        image: None,
+        colour: None,
+        bend: None,
+        unturned: Affine::IDENTITY,
+        pivot: Point::ZERO,
+        carets: Vec::new(),
+        width: 0.0,
+        width_start: 0.0,
+    };
+    let before = TextLayout { glyphs: vec![glyph(0), glyph(1)], ..TextLayout::default() };
+    assert_eq!(assert_kashida_ownership(&text, &before, &before, &red(), "duplicate glyphs", false), 0);
+
+    let mut wrong = before.clone();
+    wrong.glyphs[0].run = 1;
+    assert!(std::panic::catch_unwind(|| assert_kashida_ownership(&text, &before, &wrong, &red(), "changed owner", false)).is_err());
+}
+
 /// Compare authored glyph run indices before/after Insert Kashidas (matched by byte and gid;
 /// layout order can differ between point and justified area), and assert every inserted tatweel
 /// uses the base letter's paint at the cluster start—not `mark_fill`. When `require_mark_last`,
@@ -525,16 +562,17 @@ fn assert_kashida_ownership(
     what: &str,
     require_mark_last: bool,
 ) -> usize {
-    let mut before_runs: std::collections::HashMap<(usize, u32), Vec<usize>> = std::collections::HashMap::new();
+    let mut before_runs: std::collections::HashMap<(usize, u32), std::collections::VecDeque<usize>> = std::collections::HashMap::new();
     for g in before.glyphs.iter().filter(|g| g.len > 0) {
-        before_runs.entry((g.byte, g.gid)).or_default().push(g.run);
+        before_runs.entry((g.byte, g.gid)).or_default().push_back(g.run);
     }
     let mut after_n = 0;
     for g in with_kashida.glyphs.iter().filter(|g| g.len > 0) {
         after_n += 1;
         let runs =
             before_runs.get_mut(&(g.byte, g.gid)).unwrap_or_else(|| panic!("{what}: authored glyph {} at {} missing before kashida", g.gid, g.byte));
-        let want_run = runs.pop().unwrap_or_else(|| panic!("{what}: no remaining before-run for {} at {}", g.gid, g.byte));
+        // Duplicate glyphs at the same cluster byte retain their occurrence order.
+        let want_run = runs.pop_front().unwrap_or_else(|| panic!("{what}: no remaining before-run for {} at {}", g.gid, g.byte));
         assert_eq!(g.run, want_run, "{what}: authored run at {} gid {}", g.byte, g.gid);
         let want_fill = coloured.runs.get(want_run).map(|r| &r.style.fill).unwrap_or_else(|| panic!("{what}: missing run {want_run}"));
         assert_eq!(&run_of(coloured, g).style.fill, want_fill, "{what}: authored fill at {}", g.byte);