add tests for mistral interface

tests/providers/test_mistral_interface.py

@@ -0,0 +1,50 @@
+import pytest
+from unittest.mock import patch, MagicMock
+
+from mistralai.models.chat_completion import ChatMessage
+
+from aimodels.providers.mistral_interface import MistralInterface
+
+
+@pytest.fixture(autouse=True)
+def set_api_key_env_var(monkeypatch):
+    """Fixture to set environment variables for tests."""
+    monkeypatch.setenv("MISTRAL_API_KEY", "test-api-key")
+
+
+def test_mistral_interface():
+    """High-level test that the interface is initialized and chat completions are requested successfully."""
+
+    user_greeting = "Hello!"
+    message_history = [{"role": "user", "content": user_greeting}]
+    selected_model = "our-favorite-model"
+    chosen_temperature = 0.75
+    response_text_content = "mocked-text-response-from-model"
+
+    interface = MistralInterface()
+    mock_response = MagicMock()
+    mock_response.choices = [MagicMock()]
+    mock_response.choices[0].message = MagicMock()
+    mock_response.choices[0].message.content = response_text_content
+
+    with patch.object(
+        interface.mistral_client, "chat", return_value=mock_response
+    ) as mock_create:
+        response = interface.chat_completion_create(
+            messages=message_history,
+            model=selected_model,
+            temperature=chosen_temperature,
+        )
+
+        transformed_message_history = [
+            ChatMessage(role=message["role"], content=message["content"])
+            for message in message_history
+        ]
+
+        mock_create.assert_called_with(
+            messages=transformed_message_history,
+            model=selected_model,
+            temperature=chosen_temperature,
+        )
+
+        assert response.choices[0].message.content == response_text_content