add first unit test

.gitignore

@@ -1,2 +1,3 @@
 **/CLAUDE.md
 **/system_prompt.md
+**/__pycache__/**

test_app.py

@@ -0,0 +1,38 @@
+import os
+import pytest
+from unittest.mock import Mock, patch, MagicMock
+from app import generate_prompt
+
+TEST_SYSTEM_PROMPT = "PROMPT ROULETTE ..."
+TEST_OPENAI_API_KEY = "sk-prompt-roulette-..."
+TEST_OPENAI_CHAT_RESPONSE_CONTENT = "You are ..."
+TEST_GRADIO_SESSION_HASH = "prompt-roulette-session-..."
+
+class TestGeneratePrompt:
+    @patch("app.OpenAI")
+    @patch.dict(os.environ, {
+        "SYSTEM_PROMPT": TEST_SYSTEM_PROMPT,
+        "OPENAI_API_KEY": TEST_OPENAI_API_KEY
+    })
+    def test_generate_prompt_success(self, mock_openai_class):
+        """Test a successful OpenAI API call."""
+        # Mock the OpenAI client and response
+        mock_client = Mock()
+        mock_openai_class.return_value = mock_client
+
+        mock_response = Mock()
+        mock_response.choices = [Mock()]
+        mock_response.choices[0].message = Mock()
+        mock_response.choices[0].message.content = TEST_OPENAI_CHAT_RESPONSE_CONTENT
+
+        mock_client.chat.completions.create.return_value = mock_response
+
+        # Mock the gradio request
+        mock_gradio_request = Mock()
+        mock_gradio_request.session_hash = TEST_GRADIO_SESSION_HASH
+
+        # Call the function
+        result = generate_prompt(mock_gradio_request)
+
+        assert result == TEST_OPENAI_CHAT_RESPONSE_CONTENT
+