Add UT for notifyWorks with unreachable server

userapi/internal/device_list_update_test.go

@@ -27,6 +27,7 @@ import (
 	"testing"
 	"time"
 
+	api2 "github.com/matrix-org/dendrite/federationapi/api"
 	"github.com/matrix-org/dendrite/federationapi/statistics"
 	"github.com/matrix-org/dendrite/internal/caching"
 	"github.com/matrix-org/dendrite/internal/sqlutil"
@@ -480,3 +481,65 @@ func Test_dedupeStateList(t *testing.T) {
 		})
 	}
 }
+
+func TestDeviceListUpdaterIgnoreBlacklisted(t *testing.T) {
+	unreachableServer := spec.ServerName("notlocalhost")
+
+	updater := DeviceListUpdater{
+		workerChans: make([]chan spec.ServerName, 1),
+		isBlacklistedOrBackingOffFn: func(s spec.ServerName) (*statistics.ServerStatistics, error) {
+			switch s {
+			case unreachableServer:
+				return nil, &api2.FederationClientError{Blacklisted: true}
+			}
+			return nil, nil
+		},
+		mu:             &sync.Mutex{},
+		userIDToChanMu: &sync.Mutex{},
+		userIDToChan:   make(map[string]chan bool),
+		userIDToMutex:  make(map[string]*sync.Mutex),
+	}
+	workerCh := make(chan spec.ServerName)
+	updater.workerChans[0] = workerCh
+
+	// happy case
+	alice := "@alice:localhost"
+	aliceCh := updater.assignChannel(alice)
+
+	// failing case
+	bob := "@bob:" + unreachableServer
+	bobCh := updater.assignChannel(string(bob))
+
+	expectedServers := map[spec.ServerName]struct{}{
+		"localhost": {},
+	}
+	unexpectedServers := make(map[spec.ServerName]struct{})
+
+	go func() {
+		for serverName := range workerCh {
+			switch serverName {
+			case "localhost":
+				delete(expectedServers, serverName)
+				aliceCh <- true // unblock notifyWorkers
+			case "notlocalhost": // this should not happen as it is "filtered" away by the blacklist
+				unexpectedServers[serverName] = struct{}{}
+				bobCh <- true
+			default:
+				unexpectedServers[serverName] = struct{}{}
+			}
+		}
+	}()
+
+	// alice is not blacklisted
+	updater.notifyWorkers(alice)
+	// bob is blacklisted
+	updater.notifyWorkers(string(bob))
+
+	for server := range expectedServers {
+		t.Errorf("Server still in expectedServers map: %s", server)
+	}
+
+	for server := range unexpectedServers {
+		t.Errorf("unexpected server in result: %s", server)
+	}
+}