WIP before rebase

tests/test_app.py

@@ -1,15 +1,45 @@
 import sys, os
 sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), "..")))
+import pytest
+from unittest.mock import patch, MagicMock
+
+@pytest.fixture(autouse=True, scope="session")
+def patch_hf_classes():
+    with patch("app.AutoTokenizer") as mock_tokenizer_cls, \
+         patch("app.AutoModelForCausalLM") as mock_model_cls:
+
+        # Fake tokenizer
+        mock_tokenizer = MagicMock()
+        mock_tokenizer.pad_token_id = 0
+        mock_tokenizer.eos_token_id = 1
+        mock_tokenizer.chat_template = "{% for message in messages %}{{ message['role'] }}: {{ message['content'] }}{% endfor %}"
+        mock_tokenizer.apply_chat_template.return_value = "mock_prompt"
+        mock_tokenizer.__call__.return_value = {"input_ids": [[0, 1]]}
+        mock_tokenizer.decode.return_value = "• Easy switch"
+
+        mock_tokenizer_cls.from_pretrained.return_value = mock_tokenizer
+
+        mock_model = MagicMock()
+        mock_model.generate.return_value = [[0, 1, 2, 3]]
+        mock_model_cls.from_pretrained.return_value = mock_model
+
+        yield 
 
 import app
 
+
 def test_calculate_footprint():
-    """Check CO2 footprint calculation."""
     total, stats = app.calculate_footprint(
         car_km=10, bus_km=5, train_km=2, air_km_week=50,
         meat_meals=3, vegetarian_meals=2, vegan_meals=1,
     )
-
     assert total > 0
     assert "trees" in stats
     assert isinstance(stats["trees"], int)
+
+
+def test_chat_mock_runs():
+    """chat() should return mocked text without loading real model."""
+    out = app.chat(messages=[{"role": "user", "content": "Hello"}], history=[])
+    assert isinstance(out, str)
+    assert "Easy switch" in out or "•" in out