add error handling for missing env vars and respective tests

app.py

@@ -50,9 +50,19 @@ def generate_prompt(request: gr.Request):
     try:
         # Read the system prompt from file
         system_prompt = os.environ.get("SYSTEM_PROMPT")
+        api_key = os.environ.get("OPENAI_API_KEY")
+
+        # Validate required environment variables
+        if not system_prompt:
+            logger.error("SYSTEM_PROMPT environment variable not set")
+            return "⚠️  Service temporarily unavailable. Please try again later."
+
+        if not api_key:
+            logger.error("OPENAI_API_KEY environment variable not set")
+            return "⚠️  Service temporarily unavailable. Please try again later."
 
         # Initialize OpenAI client
-        client = OpenAI(api_key=os.environ.get("OPENAI_API_KEY"))
+        client = OpenAI(api_key=api_key)
 
         # Make API call
         session_id = request.session_hash
@@ -72,7 +82,7 @@ def generate_prompt(request: gr.Request):
 
     except Exception as e:
         logger.error(f"API request failed - Session: {session_id} - Error: {str(e)}")
-        return "Could not generate a prompt. No fish today."
+        return "⚠️  Could not generate a prompt. No fish today."
 
 with gr.Blocks(
     title="Prompt Roulette",

test_app.py

@@ -9,6 +9,10 @@ TEST_OPENAI_CHAT_RESPONSE_CONTENT = "You are ..."
 TEST_GRADIO_SESSION_HASH = "prompt-roulette-session-..."
 
 class TestGeneratePrompt:
+    def test_gradio_app_loads(self):
+        from app import demo
+        assert demo is not None
+
     @patch("app.OpenAI")
     @patch.dict(os.environ, {
         "SYSTEM_PROMPT": TEST_SYSTEM_PROMPT,
@@ -55,10 +59,14 @@ class TestGeneratePrompt:
         # Call the function
         result = generate_prompt(mock_gradio_request)
 
-        assert result == "Could not generate a prompt. No fish today."
+        assert result == "⚠️  Could not generate a prompt. No fish today."
 
     @patch("app.logger")
     @patch("app.OpenAI")
+    @patch.dict(os.environ, {
+        "SYSTEM_PROMPT": TEST_SYSTEM_PROMPT,
+        "OPENAI_API_KEY": TEST_OPENAI_API_KEY
+    })
     def test_logging_on_success(self, mock_openai_class, mock_logger):
         """Test that logging works correctly on successful API call."""
         api_total_token_count = 500
@@ -92,6 +100,10 @@ class TestGeneratePrompt:
 
     @patch("app.logger")
     @patch("app.OpenAI")
+    @patch.dict(os.environ, {
+        "SYSTEM_PROMPT": TEST_SYSTEM_PROMPT,
+        "OPENAI_API_KEY": TEST_OPENAI_API_KEY
+    })
     def test_logging_on_failure(self, mock_openai_class, mock_logger):
         """Test that logging works correctly on failed API call."""
         api_error_message = "OpenAI is down."
@@ -111,3 +123,16 @@ class TestGeneratePrompt:
         mock_logger.error.assert_any_call(
             f"API request failed - Session: {TEST_GRADIO_SESSION_HASH} - Error: {api_error_message}"
         )
+
+    @patch.dict(os.environ, {}, clear=True)
+    def test_missing_env_vars(self):
+        """Test what happens when SYSTEM_PROMPT and/or OPENAI_API_KEY are missing."""
+        # 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 ==  "⚠️  Service temporarily unavailable. Please try again later."
+