tests: add relative link test

Author: OgeonX-Ai

tests/test_links.py

@@ -0,0 +1,21 @@
+import subprocess
+import sys
+import unittest
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+
+
+class LinkTests(unittest.TestCase):
+    def test_relative_links_are_valid(self):
+        result = subprocess.run(
+            [sys.executable, str(ROOT / 'scripts' / 'check_links.py')],
+            cwd=ROOT,
+            text=True,
+            capture_output=True,
+        )
+        self.assertEqual(result.returncode, 0, result.stdout + result.stderr)
+
+
+if __name__ == '__main__':
+    unittest.main()