Add rust-ts-mode font-locking tests (bug#70464)

* test/lisp/progmodes/rust-ts-mode-tests.el: New file for rust-ts-mode
tests.
* test/lisp/progmodes/rust-ts-mode-resources/font-lock.rs: New file
with rust-ts-mode font-locking tests. New tests added for macro
font-locking (bug#70464) and function signatures
(bug#70465).

test/lisp/progmodes/rust-ts-mode-resources/font-lock.rs

@@ -0,0 +1,25 @@
+// -*- rust-ts-mode-indent-offset: 0 -*-
+// Trait with function signature
+trait Foo {
+    fn foo();
+//      ^ font-lock-function-name-face
+}
+
+// Macros
+macro_rules! unsafe_foo {
+    ($env:expr, $name:ident $(, $args:expr)*) => {
+//    ^ font-lock-variable-name-face
+//         ^ font-lock-type-face
+//                ^ font-lock-variable-name-face
+//                      ^ font-lock-type-face
+//                          ^ font-lock-operator-face
+//                                ^ font-lock-variable-name-face
+//                                      ^ font-lock-type-face
+//                                         ^ font-lock-operator-face
+        {
+            foo!($env, $name $(, $args)*);
+//                ^ font-lock-variable-use-face
+//                           ^ font-lock-operator-face
+//                                     ^ font-lock-operator-face
+        }
+    };

test/lisp/progmodes/rust-ts-mode-tests.el

@@ -0,0 +1,34 @@
+;;; rust-ts-mode-tests.el --- Tests for rust-ts-mode -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2023-2024 Free Software Foundation, Inc.
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Code:
+
+(require 'ert)
+(require 'ert-font-lock)
+(require 'ert-x)
+(require 'treesit)
+
+(ert-deftest rust-ts-test-font-lock ()
+  (skip-unless (treesit-ready-p 'rust))
+  (let ((treesit-font-lock-level 4))
+    (ert-font-lock-test-file (ert-resource-file "font-lock.rs") 'rust-ts-mode)))
+
+(provide 'rust-ts-mode-tests)
+
+;;; rust-ts-mode-tests.el ends here