diff --git a/lib/discovery/plugins/testutil/util.go b/lib/discovery/plugins/testutil/util.go
index abf743b..5178542 100644
--- a/lib/discovery/plugins/testutil/util.go
+++ b/lib/discovery/plugins/testutil/util.go
@@ -35,7 +35,12 @@
 func Scan(ctx *context.T, p idiscovery.Plugin, interfaceName string) (<-chan *idiscovery.AdInfo, func(), error) {
 	ctx, cancel := context.WithCancel(ctx)
 	scanCh := make(chan *idiscovery.AdInfo)
-	callback := func(ad *idiscovery.AdInfo) { scanCh <- ad }
+	callback := func(ad *idiscovery.AdInfo) {
+		select {
+		case scanCh <- ad:
+		case <-ctx.Done():
+		}
+	}
 	var wg sync.WaitGroup
 	wg.Add(1)
 	if err := p.Scan(ctx, interfaceName, callback, wg.Done); err != nil {
diff --git a/lib/discovery/test/directory_test.go b/lib/discovery/test/directory_test.go
index 914923b..8b2422b 100644
--- a/lib/discovery/test/directory_test.go
+++ b/lib/discovery/test/directory_test.go
@@ -153,7 +153,13 @@
 	}
 
 	updateCh := make(chan *idiscovery.AdInfo)
-	if err = mockPlugin.Scan(ctx, "", func(ad *idiscovery.AdInfo) { updateCh <- ad }, func() {}); err != nil {
+	callback := func(ad *idiscovery.AdInfo) {
+		select {
+		case updateCh <- ad:
+		case <-ctx.Done():
+		}
+	}
+	if err = mockPlugin.Scan(ctx, "", callback, func() {}); err != nil {
 		t.Fatal(err)
 	}
 	<-updateCh