Test the group check's answer without swapping standard output, and wait for a take-in to forget a new module's wait (issue 1299, C2; issue 1851, A5)

cmd/mesh-controller/new_module_on_merge_test.go

@@ -58,9 +58,10 @@ func TestAMergeAddingAModuleEndsRegisteredFromItsKeyAndAsksNoBuild(t *testing.T)
 		_, known := inventoryHolds(t, inv, "systemd-resolved")
 		return known
 	})
-	if obs := newModuleObservations(time.Now().Add(time.Hour)); len(obs) != 0 {
-		t.Fatalf("a registered module is still named waiting: %+v", obs)
-	}
+	// The take-in forgets the wait just after the registration it made is seen.
+	becomes(t, 5*time.Second, "the registered module no longer named waiting", func() bool {
+		return len(newModuleObservations(time.Now().Add(time.Hour))) == 0
+	})
 	requests, err := inv.RequestsNamed(ctx, inventory.BuildRequest{Repository: "novox/mesh-catalog",
 		Path: "modules/systemd-resolved"}.Name())
 	if err != nil || len(requests) != 0 {