checker: one integration test through the real bus proves a merge turn holds a check off until it goes and a carry of unchanged digests runs nothing; it extends the equal-inputs test, so the count stays (ADR 0548 §3, §5; issue 568 D7)

modules/mesh-delivery-checker/cmd/mesh-delivery-checker/integration_test.go

@@ -305,7 +305,8 @@ func startBed(t *testing.T) *bed {
 	for name, history := range map[string]int{delivery.CheckerVerdictsBucket: delivery.CheckerVerdictsHistory, delivery.CheckerKeptBucket: delivery.CheckerKeptHistory,
 		delivery.CheckerOwedBucket: delivery.CheckerOwedHistory, delivery.PreviewsBucket: delivery.PreviewsHistory, delivery.CandidatesBucket: delivery.CandidatesHistory,
 		delivery.ModulesBucket: delivery.ModulesHistory, delivery.ManifestsBucket: delivery.ManifestsHistory, delivery.SourceBucket: delivery.SourceHistory,
-		delivery.PresenceBucket: delivery.PresenceHistory, delivery.HaveBucket: delivery.HaveHistory, check.TriesBucket: 1} {
+		delivery.PresenceBucket: delivery.PresenceHistory, delivery.HaveBucket: delivery.HaveHistory, check.TriesBucket: 1,
+		delivery.TurnsBucket: delivery.TurnsHistory} {
 		kv, err := js.CreateKeyValue(ctx, jetstream.KeyValueConfig{Bucket: name, History: uint8(history)})
 		if err != nil {
 			t.Fatal(err)
@@ -507,9 +508,12 @@ func TestCheckerJudgesACandidateAndOwesItsStatus(t *testing.T) { // N6/AC5, 1300
 	}
 }
 
-// TestACheckOfEqualInputsRunsNothing: a second candidate (another head, the same digests) is checked with every package
-// taken from the first's kept verdicts: no test step runs and no second kept key appears.
-func TestACheckOfEqualInputsRunsNothing(t *testing.T) { // 1287/AC5, 1288/AC6, 1929/AC2
+// TestACheckOrACarryOfEqualInputsRunsNothing: a second candidate (another head, the same digests) is checked with every
+// package taken from the first's kept verdicts: no test step runs and no second kept key appears. Then, through the real bus
+// (novox/hq ADR 0548 §3, §5): a third candidate is not claimed while the gate's merge turn on its repository stands, and is
+// claimed when the turn's key is deleted; and a move of the trunk carries the first verdict on the recheck stream by its
+// unchanged digests, running no test, the verdict naming the trunk it was carried from.
+func TestACheckOrACarryOfEqualInputsRunsNothing(t *testing.T) { // 1287/AC5, 1288/AC6, 1929/AC2, ADR 0548 §3, §5
 	b := startBed(t)
 	first := b.candidate(t, "feat/x", pull(repo, 7, head1))
 	b.start(t, nil)
@@ -526,6 +530,42 @@ func TestACheckOfEqualInputsRunsNothing(t *testing.T) { // 1287/AC5, 1288/AC6, 1
 	if got := keptCount(t, b); got != kept {
 		t.Errorf("%d kept keys, was %d", got, kept)
 	}
+
+	// §3: the gate's turn on the repository holds a new check off; its delete claims it.
+	at := time.Now().UTC()
+	turn, err := delivery.EncodeTurn(delivery.Turn{Repository: repo, Waiting: []delivery.TurnWait{{Group: "fix/other", Heads: "0123456789ab", Approved: at, Since: at}}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	tk, _ := delivery.TurnsKey(repo)
+	if _, err := b.buckets[delivery.TurnsBucket].Put(b.ctx, tk, turn); err != nil {
+		t.Fatal(err)
+	}
+	time.Sleep(300 * time.Millisecond) // the checker hears the turn
+	third := b.candidate(t, "feat/z", pull(repo, 9, "3333333333333333333333333333333333333333"))
+	time.Sleep(time.Second)
+	if _, err := b.buckets[delivery.CheckerVerdictsBucket].Get(b.ctx, third); !errors.Is(err, jetstream.ErrKeyNotFound) {
+		t.Fatalf("verdicts.%s exists (%v) while a merge turn holds its repository", third, err)
+	}
+	if err := b.buckets[delivery.TurnsBucket].Delete(b.ctx, tk); err != nil {
+		t.Fatal(err)
+	}
+	b.verdict(t, third, ended)
+
+	// §5: the trunk moves; the first verdict is carried by its digests, nothing runs.
+	tests = b.fake.count("mesh-build-go.build_go_test")
+	const moved = "abababababababababababababababababababab"
+	b.setTrunk(t, map[string]string{repo: moved})
+	c := b.verdict(t, first, func(v delivery.Verdict) bool { return ended(v) && v.Trunk[repo] == moved })
+	if c.State != delivery.VerdictPass || c.CarriedFrom[repo] != trunk || c.Levels[delivery.LevelUnit].Run != 0 || c.Levels[delivery.LevelIntegration].Run != 0 {
+		t.Fatalf("the carried verdict = %+v, want a pass carried from %s with no test run", c, trunk[:12])
+	}
+	if got := b.fake.count("mesh-build-go.build_go_test"); got != tests {
+		t.Errorf("build_go_test called %d times on the carry, was %d: a carry of unchanged digests runs nothing", got, tests)
+	}
+	if o := b.owed(t, 7, head1, "success"); !strings.HasPrefix(o.Text, "pass 111111111111 on abababababab | carried from aaaaaaaaaaaa") {
+		t.Errorf("the carried status says %q", o.Text)
+	}
 }
 
 func keptCount(t *testing.T, b *bed) int {