diff --git a/tests/test_config.py b/tests/test_config.py
new file mode 100644
index 0000000..78c58c9
--- /dev/null
+++ b/tests/test_config.py
@@ -0,0 +1,24 @@
+import json
+
+import pytest
+
+from ai_typewriter.config import load_config
+
+
+def test_load_default_config(tmp_path):
+    path = tmp_path / "config.json"
+    path.write_text(json.dumps({"provider": "ollama"}), encoding="utf-8")
+
+    cfg = load_config(path)
+
+    assert cfg.provider == "ollama"
+    assert cfg.hotkey == "ctrl+alt+a"
+    assert "Réponds directement" in cfg.system_prompt
+
+
+def test_reject_invalid_provider(tmp_path):
+    path = tmp_path / "config.json"
+    path.write_text(json.dumps({"provider": "bad"}), encoding="utf-8")
+
+    with pytest.raises(ValueError):
+        load_config(path)