Significantly simpler and malleable test setup (#360)

* Significantly simpler and malleable test setup

* convert memory tests

* refactor fixtures and add support for composable fixtures

* Fix memory to use the newer fixture organization

* Get agents tests working

* Safety tests work

* yet another refactor to make this more general

now it accepts --inference-model, --safety-model options also

* get multiple providers working for meta-reference (for inference + safety)

* Add README.md

---------

Co-authored-by: Ashwin Bharambe <ashwin@meta.com>

llama_stack/providers/tests/inference/fixtures.py

@@ -0,0 +1,120 @@
+# 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 os
+
+import pytest
+import pytest_asyncio
+
+from llama_stack.distribution.datatypes import Api, Provider
+
+from llama_stack.providers.adapters.inference.fireworks import FireworksImplConfig
+from llama_stack.providers.adapters.inference.ollama import OllamaImplConfig
+from llama_stack.providers.adapters.inference.together import TogetherImplConfig
+from llama_stack.providers.impls.meta_reference.inference import (
+    MetaReferenceInferenceConfig,
+)
+from llama_stack.providers.tests.resolver import resolve_impls_for_test_v2
+from ..conftest import ProviderFixture
+from ..env import get_env_or_fail
+
+
+@pytest.fixture(scope="session")
+def inference_model(request):
+    if hasattr(request, "param"):
+        return request.param
+    return request.config.getoption("--inference-model", None)
+
+
+@pytest.fixture(scope="session")
+def inference_meta_reference(inference_model) -> ProviderFixture:
+    inference_model = (
+        [inference_model] if isinstance(inference_model, str) else inference_model
+    )
+
+    return ProviderFixture(
+        providers=[
+            Provider(
+                provider_id=f"meta-reference-{i}",
+                provider_type="meta-reference",
+                config=MetaReferenceInferenceConfig(
+                    model=m,
+                    max_seq_len=4096,
+                    create_distributed_process_group=False,
+                    checkpoint_dir=os.getenv("MODEL_CHECKPOINT_DIR", None),
+                ).model_dump(),
+            )
+            for i, m in enumerate(inference_model)
+        ]
+    )
+
+
+@pytest.fixture(scope="session")
+def inference_ollama(inference_model) -> ProviderFixture:
+    inference_model = (
+        [inference_model] if isinstance(inference_model, str) else inference_model
+    )
+    if "Llama3.1-8B-Instruct" in inference_model:
+        pytest.skip("Ollama only supports Llama3.2-3B-Instruct for testing")
+
+    return ProviderFixture(
+        providers=[
+            Provider(
+                provider_id="ollama",
+                provider_type="remote::ollama",
+                config=OllamaImplConfig(
+                    host="localhost", port=os.getenv("OLLAMA_PORT", 11434)
+                ).model_dump(),
+            )
+        ],
+    )
+
+
+@pytest.fixture(scope="session")
+def inference_fireworks() -> ProviderFixture:
+    return ProviderFixture(
+        providers=[
+            Provider(
+                provider_id="fireworks",
+                provider_type="remote::fireworks",
+                config=FireworksImplConfig(
+                    api_key=get_env_or_fail("FIREWORKS_API_KEY"),
+                ).model_dump(),
+            )
+        ],
+    )
+
+
+@pytest.fixture(scope="session")
+def inference_together() -> ProviderFixture:
+    return ProviderFixture(
+        providers=[
+            Provider(
+                provider_id="together",
+                provider_type="remote::together",
+                config=TogetherImplConfig().model_dump(),
+            )
+        ],
+        provider_data=dict(
+            together_api_key=get_env_or_fail("TOGETHER_API_KEY"),
+        ),
+    )
+
+
+INFERENCE_FIXTURES = ["meta_reference", "ollama", "fireworks", "together"]
+
+
+@pytest_asyncio.fixture(scope="session")
+async def inference_stack(request):
+    fixture_name = request.param
+    inference_fixture = request.getfixturevalue(f"inference_{fixture_name}")
+    impls = await resolve_impls_for_test_v2(
+        [Api.inference],
+        {"inference": inference_fixture.providers},
+        inference_fixture.provider_data,
+    )
+
+    return (impls[Api.inference], impls[Api.models])