A group member's own check runs its repository's check alone, a cycle fails the composed check, and mark-ready leaves the delivery seat (issue 977, part D, ADR 0403)

cmd/mesh-controller/batches_test.go

@@ -119,6 +119,24 @@ func everyHeadWaits(t *testing.T) {
 	t.Cleanup(func() { deliveryGroupOf = was })
 }
 
+// groupStates stubs mesh-delivery's word on one group: its members and their states, which a test changes as the
+// members merge.
+func groupStates(t *testing.T, head string, states map[string]string) {
+	t.Helper()
+	was := deliveryGroupOf
+	deliveryGroupOf = func(_ context.Context, _ bool, asked string) ([]groupMember, bool, error) {
+		if asked != head {
+			return nil, false, nil
+		}
+		var members []groupMember
+		for repository, state := range states {
+			members = append(members, groupMember{Repository: repository, State: state})
+		}
+		return members, true, nil
+	}
+	t.Cleanup(func() { deliveryGroupOf = was })
+}
+
 // fromHead is a merge from a head branch a test names: merges from one head are members of one delivery group,
 // related by it (novox/hq ADR 0304 decision 1), so they share a batch whatever else they share.
 func fromHead(m link.SourceMoved, head string) link.SourceMoved {