Start some integration tests with an OpenAI client

This starts to stub in some integration tests for the
OpenAI-compatible server APIs using an OpenAI client.

Signed-off-by: Ben Browning <bbrownin@redhat.com>

tests/integration/inference/test_openai_completion.py

@@ -0,0 +1,83 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+
+import pytest
+from openai import OpenAI
+
+from llama_stack.distribution.library_client import LlamaStackAsLibraryClient
+
+from ..test_cases.test_case import TestCase
+
+
+def skip_if_model_doesnt_support_openai_completion(client_with_models, model_id):
+    if isinstance(client_with_models, LlamaStackAsLibraryClient):
+        pytest.skip("OpenAI completions are not supported when testing with library client yet.")
+
+    models = {m.identifier: m for m in client_with_models.models.list()}
+    models.update({m.provider_resource_id: m for m in client_with_models.models.list()})
+    provider_id = models[model_id].provider_id
+    providers = {p.provider_id: p for p in client_with_models.providers.list()}
+    provider = providers[provider_id]
+    if provider.provider_type in (
+        "inline::meta-reference",
+        "inline::sentence-transformers",
+        "inline::vllm",
+        "remote::bedrock",
+        "remote::cerebras",
+        "remote::databricks",
+        "remote::nvidia",
+        "remote::runpod",
+        "remote::sambanova",
+        "remote::tgi",
+    ):
+        pytest.skip(f"Model {model_id} hosted by {provider.provider_type} doesn't support OpenAI completions.")
+
+
+@pytest.fixture
+def openai_client(client_with_models, text_model_id):
+    skip_if_model_doesnt_support_openai_completion(client_with_models, text_model_id)
+    base_url = f"{client_with_models.base_url}/v1/openai/v1"
+    return OpenAI(base_url=base_url, api_key="bar")
+
+
+@pytest.mark.parametrize(
+    "test_case",
+    [
+        "inference:completion:sanity",
+    ],
+)
+def test_openai_completion_non_streaming(openai_client, text_model_id, test_case):
+    tc = TestCase(test_case)
+
+    response = openai_client.completions.create(
+        model=text_model_id,
+        prompt=tc["content"],
+        stream=False,
+    )
+    assert len(response.choices) > 0
+    choice = response.choices[0]
+    assert len(choice.text) > 10
+
+
+@pytest.mark.parametrize(
+    "test_case",
+    [
+        "inference:completion:sanity",
+    ],
+)
+def test_openai_completion_streaming(openai_client, text_model_id, test_case):
+    tc = TestCase(test_case)
+
+    response = openai_client.completions.create(
+        model=text_model_id,
+        prompt=tc["content"],
+        stream=True,
+        max_tokens=50,
+    )
+    streamed_content = [chunk.choices[0].text for chunk in response]
+    content_str = "".join(streamed_content).lower().strip()
+    assert len(content_str) > 10