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/memory/fixtures.py

@@ -0,0 +1,85 @@
+# 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.memory.pgvector import PGVectorConfig
+from llama_stack.providers.adapters.memory.weaviate import WeaviateConfig
+from llama_stack.providers.impls.meta_reference.memory import FaissImplConfig
+
+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 memory_meta_reference() -> ProviderFixture:
+    return ProviderFixture(
+        providers=[
+            Provider(
+                provider_id="meta-reference",
+                provider_type="meta-reference",
+                config=FaissImplConfig().model_dump(),
+            )
+        ],
+    )
+
+
+@pytest.fixture(scope="session")
+def memory_pgvector() -> ProviderFixture:
+    return ProviderFixture(
+        providers=[
+            Provider(
+                provider_id="pgvector",
+                provider_type="remote::pgvector",
+                config=PGVectorConfig(
+                    host=os.getenv("PGVECTOR_HOST", "localhost"),
+                    port=os.getenv("PGVECTOR_PORT", 5432),
+                    db=get_env_or_fail("PGVECTOR_DB"),
+                    user=get_env_or_fail("PGVECTOR_USER"),
+                    password=get_env_or_fail("PGVECTOR_PASSWORD"),
+                ).model_dump(),
+            )
+        ],
+    )
+
+
+@pytest.fixture(scope="session")
+def memory_weaviate() -> ProviderFixture:
+    return ProviderFixture(
+        providers=[
+            Provider(
+                provider_id="weaviate",
+                provider_type="remote::weaviate",
+                config=WeaviateConfig().model_dump(),
+            )
+        ],
+        provider_data=dict(
+            weaviate_api_key=get_env_or_fail("WEAVIATE_API_KEY"),
+            weaviate_cluster_url=get_env_or_fail("WEAVIATE_CLUSTER_URL"),
+        ),
+    )
+
+
+MEMORY_FIXTURES = ["meta_reference", "pgvector", "weaviate"]
+
+
+@pytest_asyncio.fixture(scope="session")
+async def memory_stack(request):
+    fixture_name = request.param
+    fixture = request.getfixturevalue(f"memory_{fixture_name}")
+
+    impls = await resolve_impls_for_test_v2(
+        [Api.memory],
+        {"memory": fixture.providers},
+        fixture.provider_data,
+    )
+
+    return impls[Api.memory], impls[Api.memory_banks]