fix(typst): anchor color-token search in border parsing

CSS `border` and `border-color` declarations lost any tokens that
preceded an `rgb()` / `rgba()` color because `s:find('%w+%b()', start)`
in `translate_border` and `consume_color` is unanchored — it would skip
past width/style (or earlier color) tokens to match the parens-bearing
form. With `border: 0px solid rgb(255, 0, 0)` the width and style were
never seen, leaving the default `medium` (2.25pt) thickness.

Adding `^` anchors the search at `start` so the leading token is
consumed first, matching how named/hex colors already worked.

Also adds a luaunit-based unit-test convention:
- tests/unit-lua/*.test.lua  (luaunit suites; ends in os.exit(lu...))
- tests/smoke/lua-unit/lua-unit.test.ts runs each via `quarto run` with
  LUA_PATH set so `require('luaunit')` and filter-module requires work.

Fixes #14460

Author: gordonwoodhull

news/changelog-1.10.md

@@ -16,6 +16,7 @@ All changes included in 1.10:
 ### `typst`
 
 - ([#14261](https://github.com/quarto-dev/quarto-cli/issues/14261)): Fix theorem/example block titles containing inline code producing invalid Typst markup when syntax highlighting is applied.
+- ([#14460](https://github.com/quarto-dev/quarto-cli/issues/14460)): Fix CSS `border` and `border-color` declarations losing tokens that precede an `rgb()`/`rgba()` color (e.g. `border: 0px solid rgb(255, 0, 0)` rendering as a 2.25pt border instead of being suppressed).
 
 ### `revealjs`
 

src/resources/filters/modules/typst_css.lua

@@ -679,7 +679,9 @@ local function translate_border(v, warnings)
   local style = 'solid' -- css specifies none
   local paint = 'black' -- css specifies currentcolor
   parse_multiple(v, 3, function(s, start)
-    local fbeg, fend = s:find('%w+%b()', start)
+    -- '^' anchors the match at `start` so a width/style token (e.g. "0px",
+    -- "solid") preceding an rgb()/rgba() color is not skipped. See #14460.
+    local fbeg, fend = s:find('^%w+%b()', start)
     if fbeg then
       local paint2 = translate_border_color(s:sub(fbeg, fend), warnings)
       if paint2 then
@@ -728,7 +730,9 @@ local function consume_style(s, start, warnings)
 end
 
 local function consume_color(s, start, warnings)
-  local fbeg, fend = s:find('%w+%b()', start)
+  -- '^' anchors at `start` so we consume the token AT start instead of
+  -- skipping ahead to a later rgb()/rgba(). See #14460.
+  local fbeg, fend = s:find('^%w+%b()', start)
   if not fbeg then
     fbeg, fend = s:find('%S+', start)
   end

tests/smoke/lua-unit/lua-unit.test.ts

@@ -0,0 +1,67 @@
+/*
+ * lua-unit.test.ts
+ *
+ * Runs the luaunit-based Lua unit tests in tests/unit-lua/ via `quarto run`.
+ *
+ * Convention for a Lua unit test file:
+ *   - Lives under tests/unit-lua/ and ends in `.test.lua`.
+ *   - `local lu = require('luaunit')` (resolved via LUA_PATH set below).
+ *   - May `require()` any module under src/resources/filters/ or
+ *     src/resources/filters/modules/ (also on LUA_PATH).
+ *   - Mocks any filter-runtime globals it needs (param, tcontains,
+ *     format_typst_float, quarto.log.*, _quarto.*).
+ *   - Ends with `os.exit(lu.LuaUnit.run())` so failures surface as a
+ *     non-zero exit code, which fails this Deno test.
+ *
+ * To add a new Lua unit test, drop a file into tests/unit-lua/ and add its
+ * relative path to LUA_TESTS below.
+ */
+
+import { fromFileUrl, join } from "../../../src/deno_ral/path.ts";
+import { assert } from "testing/asserts";
+import { execProcess } from "../../../src/core/process.ts";
+import { quartoDevCmd } from "../../utils.ts";
+import { unitTest } from "../../test.ts";
+
+// Explicit list, relative to tests/unit-lua/. Keep alphabetized.
+const LUA_TESTS: string[] = [
+  "typst-css.test.lua",
+];
+
+const testsDir = fromFileUrl(new URL("../../", import.meta.url));
+const repoRoot = fromFileUrl(new URL("../../../", import.meta.url));
+const unitLuaDir = join(testsDir, "unit-lua");
+const filtersDir = join(repoRoot, "src", "resources", "filters");
+const filterModulesDir = join(filtersDir, "modules");
+
+// Pandoc honors LUA_PATH for `require()` resolution in lua filters.
+// The `;;` at the end preserves the default search path.
+const LUA_PATH = [
+  join(unitLuaDir, "?.lua"),
+  join(filterModulesDir, "?.lua"),
+  join(filtersDir, "?.lua"),
+  "",
+].join(";") + ";";
+
+for (const relPath of LUA_TESTS) {
+  const luaScript = join(unitLuaDir, relPath);
+  unitTest(`lua-unit > ${relPath}`, async () => {
+    const result = await execProcess(
+      {
+        cmd: quartoDevCmd(),
+        args: ["run", luaScript],
+        env: { LUA_PATH },
+      },
+      undefined,
+      undefined,
+      undefined,
+      true, // capture stdout/stderr
+    );
+    assert(
+      result.success,
+      `Lua unit test failed (exit ${result.code}): ${relPath}\n` +
+        `--- stdout ---\n${result.stdout ?? ""}\n` +
+        `--- stderr ---\n${result.stderr ?? ""}`,
+    );
+  });
+}