Task 10 of the LocalDb Phase 1 adoption plan. Two ScadaBridge site nodes
replicating the consolidated site database over loopback Kestrel h2c, through
the REAL fail-closed auth interceptor - not a stand-in.
This is the test that answers the question Phase 1 exists to answer. Every piece
upstream of it - schema helpers, DI wiring, the interceptor - can be
individually green while the pair still fails to converge.
It initializes both databases through SiteLocalDbSetup.OnReady rather than a
hand-written schema, so the tables, primary keys and registration ORDER under
test are the ones the host actually runs. A local schema would prove only that
the test agrees with itself.
Scenarios: A->B, B->A (bidirectional even though only A dials, which is what
makes failover safe in either direction), LWW convergence on a contended
operation, the event union across both nodes, and a peer-offline-then-rejoin
catch-up.
The event-union scenario is the one that pins the GUID id change: under the old
autoincrement scheme both nodes independently mint id=1,2,3..., and
last-writer-wins on the primary key would silently DESTROY one node's events
rather than merge them. Asserting the union count is what catches that.
The whole suite passes in ~0.6s, which is fast enough to be suspicious of a
vacuous pass, so it was verified red-first the hard way: deliberately mismatching
the two nodes' ApiKey turns all 5 red with 2m30s of timeouts. The tests really do
run through the interceptor and the real transport.
Node B's database survives its host teardown (registered as a pre-constructed
instance, which MS.DI does not dispose), so the rejoin scenario is a genuine
rejoin rather than a fresh node.
Offline - no docker, no external services.
Verified: build 0 warnings; IntegrationTests 80/80.
Claude-Session: https://claude.ai/code/session_01BL2Vu1ESDQ9SCN4gVKkdts
Joseph Doherty