From 01a840cc1431661b66fd3882748b8e041af67126 Mon Sep 17 00:00:00 2001
From: Dai Ha <dai.ha@magnolia-cms.com>
Date: Thu, 3 Sep 2026 13:06:11 +0700
Subject: [PATCH] #248 follow-up: drive the real backendErrorSink, not a copy
 of it

BackendOutageFlowTest held a ~30-line hand-copy of the lambda in
Fleetd.main, under a comment promising it mirrored production "EXACTLY".
That promise was the defect. The test proved the copy, so any change to
the real sink left the flow test green.

#248 made Fleetd.backendErrorSink(...) public for exactly this reason.
The test now calls it.

Measured, same mutation in the real sink (an early return after
sessions.onBackendError, dropping the cool-off and the lead nudge):

  old test (hand-copy):  Tests run: 5, Failures: 0  -- blind
  new test (real sink):  Tests run: 5, Failures: 4  -- catches it

0 compile errors in both runs, so both are real results. Production
reverted and confirmed with diff -q.

Full build: 1234 tests, 0 failures, 0 compile errors.
---
 .../fleet/inject/BackendOutageFlowTest.java   | 43 +++++--------------
 1 file changed, 10 insertions(+), 33 deletions(-)

diff --git a/fleetd/src/test/java/dev/ltms/fleet/inject/BackendOutageFlowTest.java b/fleetd/src/test/java/dev/ltms/fleet/inject/BackendOutageFlowTest.java
index c82ed4e..cf2b1ea 100644
--- a/fleetd/src/test/java/dev/ltms/fleet/inject/BackendOutageFlowTest.java
+++ b/fleetd/src/test/java/dev/ltms/fleet/inject/BackendOutageFlowTest.java
@@ -2,6 +2,7 @@ package dev.ltms.fleet.inject;
 
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import dev.ltms.fleet.Fleetd;
 import dev.ltms.fleet.config.FleetConfig;
 import dev.ltms.fleet.guard.SubscriptionGuard;
 import dev.ltms.fleet.herdr.AgentControl;
@@ -146,40 +147,16 @@ class BackendOutageFlowTest {
             pushLoop = new ReplyPushLoop(registry, new AgentControl(leadClient), inbox, scheduler, 3, 50);
             AtomicReference<ReplyPushLoop> pushLoopRef = new AtomicReference<>(pushLoop);
 
-            // --- mirrors Fleetd.main's backendErrorSink lambda EXACTLY: (1) mark BACKEND_ERROR,
-            // (2) resolve profile/credential via the roster, fail-loud + notify unmapped-target,
-            // (3) record in BackendOutagePolicy, (4) on a NEW incident, notify the lead. ------------
-            BackendErrorSink backendErrorSink = (target, matchedLine, reason) -> {
-                sessions.onBackendError(target, reason);
+            // fleetd #248 follow-up: this used to be a 30-line hand-copy of Fleetd.main's
+            // backendErrorSink lambda, with a comment promising it mirrored production "EXACTLY".
+            // That promise is exactly the problem: a copy proves the copy. Editing or deleting the
+            // real sink left this whole flow test green, because it never touched the real sink.
+            // #248 made Fleetd.backendErrorSink public precisely so a cross-package test could
+            // drive the real object, so this now calls it. Every assertion below is about
+            // production code again.
+            BackendErrorSink backendErrorSink =
+                    Fleetd.backendErrorSink(sessions, () -> profiles, outagePolicy, pushLoopRef::get);
 
-                String profileName = sessions.roster().stream()
-                        .filter(session -> target.equals(session.terminalId()))
-                        .findFirst()
-                        .map(MemberSession::profile)
-                        .orElse(null);
-                FleetConfig.Profile profile = profileName == null ? null : profiles.get(profileName);
-                if (profile == null) {
-                    ReplyPushLoop loop = pushLoopRef.get();
-                    if (loop != null) {
-                        loop.onBackendTargetUnmapped(target, reason);
-                    }
-                    return;
-                }
-                String credentialId = profile.effectiveCredentialId();
-                Optional<BackendOutagePolicy.Incident> incident = outagePolicy.record(credentialId, target, reason);
-                incident.ifPresent(inc -> {
-                    List<String> affectedProfiles = profiles.values().stream()
-                            .filter(p -> credentialId.equals(p.effectiveCredentialId()))
-                            .map(FleetConfig.Profile::profile)
-                            .sorted()
-                            .toList();
-                    ReplyPushLoop loop = pushLoopRef.get();
-                    if (loop != null) {
-                        loop.onBackendIncident(inc.id(), inc.targets(), credentialId, affectedProfiles,
-                                (int) inc.remainingCoolOffSeconds());
-                    }
-                });
-            };
             BackendErrorPatternLookup patterns = target -> Pattern.compile("(?i)503 Service Unavailable");
             resolver = new CompletionResolver(new AgentControl(herdr), rendezvous, ExhaustedPatternLookup.none(),
                     ExhaustionSink.none(), patterns, backendErrorSink);