test: factory tests — provider swap is config-only, unknown values rejected (Validation #1, #6)

LIT-2878

tests/test_litellm/proxy/agent_session_endpoints/vm_providers/test_factory.py

@@ -0,0 +1,85 @@
+"""
+Mocked tests for the `AgentVMProvider` factory.
+
+Covers Validation #1 from LIT-2878: factory returns the right impl per
+config value and rejects unknown values. Validation #6 (provider swap is
+config-only) is also exercised here — switching `vm_provider` from `noop` to
+`ec2` requires no code path change beyond the factory.
+"""
+
+from __future__ import annotations
+
+import pytest
+
+from litellm.proxy.agent_session_endpoints.vm_providers import (
+    EC2Provider,
+    NoopProvider,
+    SUPPORTED_PROVIDERS,
+    get_vm_provider,
+)
+
+
+def test_factory_default_is_noop():
+    """No `agent_settings` block at all → noop provider."""
+    provider = get_vm_provider(None)
+    assert isinstance(provider, NoopProvider)
+    assert provider.name == "noop"
+
+
+def test_factory_explicit_noop():
+    provider = get_vm_provider({"vm_provider": "noop"})
+    assert isinstance(provider, NoopProvider)
+
+
+def test_factory_ec2_with_settings():
+    settings = {
+        "vm_provider": "ec2",
+        "ec2": {
+            "default_region": "us-west-2",
+            "default_ami_id": "ami-deadbeef",
+            "default_instance_type": "t3.large",
+            "use_spot": True,
+        },
+    }
+    provider = get_vm_provider(settings)
+    assert isinstance(provider, EC2Provider)
+    assert provider.default_region == "us-west-2"
+    assert provider.default_ami_id == "ami-deadbeef"
+    assert provider.default_instance_type == "t3.large"
+    assert provider.default_use_spot is True
+
+
+def test_factory_ec2_uses_defaults_when_block_missing():
+    """`vm_provider: ec2` with no `ec2:` block still works using built-in defaults."""
+    provider = get_vm_provider({"vm_provider": "ec2"})
+    assert isinstance(provider, EC2Provider)
+    assert provider.default_region == "us-west-2"  # baked-in default
+    assert provider.default_instance_type == "t3.large"
+
+
+def test_factory_unknown_raises():
+    with pytest.raises(ValueError) as exc_info:
+        get_vm_provider({"vm_provider": "firecracker-someday"})
+    msg = str(exc_info.value)
+    assert "Unknown vm_provider" in msg
+    # Make sure the error message lists the supported providers so callers
+    # can fix their config without grep.
+    for name in SUPPORTED_PROVIDERS:
+        assert name in msg
+
+
+def test_factory_supported_providers_set():
+    assert set(SUPPORTED_PROVIDERS) >= {"noop", "ec2"}
+
+
+def test_provider_swap_is_config_only():
+    """Switching `vm_provider` is the only change required (Validation #6)."""
+    cfg_noop = {"vm_provider": "noop"}
+    cfg_ec2 = {**cfg_noop, "vm_provider": "ec2"}
+    p1 = get_vm_provider(cfg_noop)
+    p2 = get_vm_provider(cfg_ec2)
+    # Both implement AgentVMProvider — same call site can use either.
+    assert hasattr(p1, "provision") and hasattr(p2, "provision")
+    assert hasattr(p1, "terminate") and hasattr(p2, "terminate")
+    assert hasattr(p1, "status") and hasattr(p2, "status")
+    assert p1.name != p2.name