Update test_llm to omit the test when oai config is missing.

tests/unit_tests/test_llm.py

@@ -1,21 +1,25 @@
 from opto.utils.llm import AutoGenLLM
 from opto.optimizers.utils import print_color
 
-llm = AutoGenLLM()
-system_prompt = 'You are a helpful assistant.'
-user_prompt = "Hello world."
+try:
+    llm = AutoGenLLM()
+    system_prompt = 'You are a helpful assistant.'
+    user_prompt = "Hello world."
 
 
-messages = [{"role": "system", "content": system_prompt},
-            {"role": "user",   "content": user_prompt}]
+    messages = [{"role": "system", "content": system_prompt},
+                {"role": "user",   "content": user_prompt}]
 
-output = llm(messages=messages)
-# Alternatively, you can use the following code:
-# output = llm.create(messages=messages)
+    output = llm(messages=messages)
+    # Alternatively, you can use the following code:
+    # output = llm.create(messages=messages)
 
-response = output.choices[0].message.content
+    response = output.choices[0].message.content
 
 
-print_color(f'System: {system_prompt}', 'red')
-print_color(f'User: {user_prompt}', 'blue')
-print_color(f'LLM: {response}', 'green')
+    print_color(f'System: {system_prompt}', 'red')
+    print_color(f'User: {user_prompt}', 'blue')
+    print_color(f'LLM: {response}', 'green')
+except FileNotFoundError as e:
+    print_color(f'Error: {e}', 'red')
+    print_colorf('Omit the test.', 'yellow')