Initial commit: VMware vSphere API simulator scaffold.

Add the FastAPI app, PostgreSQL migrations, Docker/Helm packaging, API
contracts, docs, client examples, and the unit/integration/compatibility
test suite for local client and tooling labs without a real vCenter.

tests/unit/test_health.py

@@ -0,0 +1,87 @@
+from __future__ import annotations
+
+import asyncio
+from typing import Self
+
+import pytest
+from httpx import ASGITransport, AsyncClient
+
+from app.config import Settings
+from app.db.pool import Database
+from app.main import create_app
+
+
+class FakeDatabase:
+    def __init__(self, ready: bool) -> None:
+        self.ready = ready
+        self.connected = False
+        self.closed = False
+
+    async def connect(self) -> None:
+        self.connected = True
+
+    async def close(self) -> None:
+        self.closed = True
+
+    async def is_ready(self) -> bool:
+        return self.ready
+
+    async def __aenter__(self) -> Self:
+        await self.connect()
+        return self
+
+    async def __aexit__(self, exc_type: object, exc: object, traceback: object) -> None:
+        await self.close()
+
+
+@pytest.mark.parametrize(("database_ready", "status_code"), [(True, 200), (False, 503)])
+async def test_health_endpoints(database_ready: bool, status_code: int) -> None:
+    database = FakeDatabase(database_ready)
+
+    def factory(settings: Settings) -> Database:
+        del settings
+        return database
+
+    application = create_app(
+        Settings(contract_snapshot=None, compatibility_evidence=None),
+        factory,
+        worker_factories=(),
+    )
+    async with application.router.lifespan_context(application):
+        async with AsyncClient(
+            transport=ASGITransport(app=application, raise_app_exceptions=False),
+            base_url="http://test",
+        ) as client:
+            live = await client.get("/health/live")
+            ready = await client.get("/health/ready", headers={"X-Request-ID": "test-request"})
+
+    assert live.status_code == 200
+    assert live.json() == {"status": "ok"}
+    assert ready.status_code == status_code
+    assert ready.headers["X-Request-ID"] == "test-request"
+    assert database.connected
+    assert database.closed
+
+
+async def test_lifespan_starts_and_stops_injected_workers() -> None:
+    database = FakeDatabase(True)
+    started = asyncio.Event()
+    stopping = asyncio.Event()
+
+    class Worker:
+        async def run(self) -> None:
+            started.set()
+            await stopping.wait()
+
+        def stop(self) -> None:
+            stopping.set()
+
+    application = create_app(
+        Settings(contract_snapshot=None, compatibility_evidence=None),
+        lambda _settings: database,
+        worker_factories=(lambda _database: Worker(),),
+    )
+    async with application.router.lifespan_context(application):
+        await started.wait()
+
+    assert stopping.is_set()