Convert test_openai_model.py to proper pytest format

- Add pytest fixtures and decorators
- Replace print statements with assertions
- Fix imports and formatting
- Handle edge case where max_completion_tokens may cause empty response
- All 3 tests pass (test_basic_completion, test_system_message, test_streaming)

Author: fede-kamel

libs/oci/tests/integration_tests/chat_models/test_openai_model.py

@@ -1,83 +1,78 @@
 #!/usr/bin/env python3
-"""Quick test script for OpenAI models on OCI GenAI.
+# Copyright (c) 2025 Oracle and/or its affiliates.
+# Licensed under the Universal Permissive License v 1.0 as shown at https://oss.oracle.com/licenses/upl/
 
-This tests the rebased LangChain 1.x support with OpenAI models.
+"""Quick smoke tests for OpenAI models on OCI GenAI.
+
+These are simple smoke tests to verify LangChain 1.x support with OpenAI models.
+For comprehensive OpenAI model tests, see test_openai_models.py.
 
 Setup:
     export OCI_COMP=<your-compartment-id>
 
 Run:
-    python test_openai_model.py
+    pytest tests/integration_tests/chat_models/test_openai_model.py -v
 """
 
 import os
-import sys
 
-from langchain_core.messages import HumanMessage, SystemMessage
+import pytest
+from langchain_core.messages import AIMessage, HumanMessage, SystemMessage
+
 from langchain_oci.chat_models import ChatOCIGenAI
 
-# Configuration
-COMPARTMENT_ID = os.environ.get("OCI_COMP")
-if not COMPARTMENT_ID:
-    print("ERROR: OCI_COMP environment variable not set")
-    print("Set it with: export OCI_COMP=<your-compartment-id>")
-    sys.exit(1)
-
-MODEL_ID = "openai.gpt-oss-20b"  # or openai.gpt-oss-120b
-ENDPOINT = "https://inference.generativeai.us-chicago-1.oci.oraclecloud.com"
-
-print(f"Testing OpenAI model: {MODEL_ID}")
-print(f"Compartment: {COMPARTMENT_ID[:50]}...")
-print("-" * 60)
-
-# Create chat model
-chat = ChatOCIGenAI(
-    model_id=MODEL_ID,
-    service_endpoint=ENDPOINT,
-    compartment_id=COMPARTMENT_ID,
-    auth_type="SECURITY_TOKEN",
-    auth_profile="DEFAULT",
-    model_kwargs={
-        "temperature": 0.7,
-        "max_completion_tokens": 100,  # OpenAI uses max_completion_tokens
-    },
-)
-
-# Test 1: Basic completion
-print("\nTest 1: Basic completion")
-print("-" * 60)
-try:
-    response = chat.invoke([HumanMessage(content="Say hello in 5 words")])
-    print(f"✓ Response: {response.content}")
-except Exception as e:
-    print(f"✗ Error: {e}")
-    sys.exit(1)
-
-# Test 2: With system message
-print("\nTest 2: With system message")
-print("-" * 60)
-try:
-    response = chat.invoke([
-        SystemMessage(content="You are a helpful math tutor."),
-        HumanMessage(content="What is 15 * 23?")
-    ])
-    print(f"✓ Response: {response.content}")
-except Exception as e:
-    print(f"✗ Error: {e}")
-    sys.exit(1)
-
-# Test 3: Streaming
-print("\nTest 3: Streaming")
-print("-" * 60)
-try:
-    print("Response: ", end="", flush=True)
-    for chunk in chat.stream([HumanMessage(content="Count from 1 to 5")]):
-        print(chunk.content, end="", flush=True)
-    print("\n✓ Streaming works!")
-except Exception as e:
-    print(f"\n✗ Error: {e}")
-    sys.exit(1)
-
-print("\n" + "=" * 60)
-print("✓ All tests passed! LangChain 1.x + OpenAI model working correctly")
-print("=" * 60)
+
+@pytest.fixture
+def openai_chat():
+    """Create ChatOCIGenAI instance for OpenAI model testing."""
+    compartment_id = os.environ.get("OCI_COMP")
+    if not compartment_id:
+        pytest.skip("OCI_COMP environment variable not set")
+
+    return ChatOCIGenAI(
+        model_id="openai.gpt-oss-20b",
+        service_endpoint="https://inference.generativeai.us-chicago-1.oci.oraclecloud.com",
+        compartment_id=compartment_id,
+        auth_type="SECURITY_TOKEN",
+        auth_profile="DEFAULT",
+        model_kwargs={
+            "temperature": 0.7,
+            "max_completion_tokens": 100,
+        },
+    )
+
+
+@pytest.mark.requires("oci")
+def test_basic_completion(openai_chat):
+    """Test basic completion with OpenAI model."""
+    response = openai_chat.invoke([HumanMessage(content="Say hello in 5 words")])
+
+    assert isinstance(response, AIMessage)
+    assert isinstance(response.content, str)
+    assert len(response.content) > 0
+
+
+@pytest.mark.requires("oci")
+def test_system_message(openai_chat):
+    """Test completion with system message."""
+    response = openai_chat.invoke(
+        [
+            SystemMessage(content="You are a helpful math tutor."),
+            HumanMessage(content="What is 15 * 23?"),
+        ]
+    )
+
+    assert isinstance(response, AIMessage)
+    assert isinstance(response.content, str)
+    assert len(response.content) > 0
+
+
+@pytest.mark.requires("oci")
+def test_streaming(openai_chat):
+    """Test streaming with OpenAI model."""
+    chunks = list(openai_chat.stream([HumanMessage(content="Count from 1 to 5")]))
+
+    assert len(chunks) > 0
+    for chunk in chunks:
+        assert isinstance(chunk, AIMessage)
+        assert isinstance(chunk.content, str)