[Core] Support serving encoder/decoder models (#7258)

tests/entrypoints/openai/test_encoder_decoder.py

@@ -0,0 +1,50 @@
+import openai
+import pytest
+
+from ...utils import RemoteOpenAIServer
+
+MODEL_NAME = "facebook/bart-base"
+
+
+@pytest.fixture(scope="module")
+def server():
+    args = [
+        "--dtype",
+        "bfloat16",
+        "--enforce-eager",
+    ]
+
+    with RemoteOpenAIServer(MODEL_NAME, args) as remote_server:
+        yield remote_server
+
+
+@pytest.fixture(scope="module")
+def client(server):
+    return server.get_async_client()
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("model_name", [MODEL_NAME])
+async def test_single_completion(client: openai.AsyncOpenAI, model_name: str):
+    completion = await client.completions.create(model=model_name,
+                                                 prompt="Hello, my name is",
+                                                 max_tokens=5,
+                                                 temperature=0.0)
+
+    assert completion.id is not None
+    assert completion.choices is not None and len(completion.choices) == 1
+
+    choice = completion.choices[0]
+    assert len(choice.text) >= 5
+    assert choice.finish_reason == "length"
+    assert completion.usage == openai.types.CompletionUsage(
+        completion_tokens=5, prompt_tokens=2, total_tokens=7)
+
+    # test using token IDs
+    completion = await client.completions.create(
+        model=model_name,
+        prompt=[0, 0, 0, 0, 0],
+        max_tokens=5,
+        temperature=0.0,
+    )
+    assert len(completion.choices[0].text) >= 1