diff --git a/tests/test_config.py b/tests/test_config.py
index 4dcf7b4..d664af6 100644
--- a/tests/test_config.py
+++ b/tests/test_config.py
@@ -13,6 +13,7 @@ def test_load_default_config(tmp_path):
 
     assert cfg.provider == "ollama"
     assert cfg.hotkey == "ctrl+alt+a"
+    assert cfg.math_text_format == "unicode"
     assert "Réponds directement" in cfg.system_prompt
 
 
@@ -25,6 +26,14 @@ def test_timeout_zero_disables_timeout(tmp_path):
     assert cfg.request_timeout_seconds is None
 
 
+def test_reject_invalid_math_text_format(tmp_path):
+    path = tmp_path / "config.json"
+    path.write_text(json.dumps({"provider": "ollama", "math_text_format": "bad"}), encoding="utf-8")
+
+    with pytest.raises(ValueError):
+        load_config(path)
+
+
 def test_reject_invalid_provider(tmp_path):
     path = tmp_path / "config.json"
     path.write_text(json.dumps({"provider": "bad"}), encoding="utf-8")