diff --git a/pkg/reconciler/clusteringress/clusteringress_test.go b/pkg/reconciler/clusteringress/clusteringress_test.go
index ef07943b4c29..cd71627ebcda 100644
--- a/pkg/reconciler/clusteringress/clusteringress_test.go
+++ b/pkg/reconciler/clusteringress/clusteringress_test.go
@@ -1130,6 +1130,8 @@ func TestGlobalResyncOnUpdateNetwork(t *testing.T) {
 		if err := grp.Wait(); err != nil {
 			t.Errorf("Wait() = %v", err)
 		}
+		// To let the informers shut down.
+		time.Sleep(3 * time.Second)
 	}()
 
 	sharedClient := fakesharedclient.Get(ctx)
diff --git a/pkg/reconciler/configuration/queueing_test.go b/pkg/reconciler/configuration/queueing_test.go
index efb1399a5342..dfe2d7f2f608 100644
--- a/pkg/reconciler/configuration/queueing_test.go
+++ b/pkg/reconciler/configuration/queueing_test.go
@@ -85,7 +85,6 @@ func getTestConfiguration() *v1alpha1.Configuration {
 }
 
 func TestNewConfigurationCallsSyncHandler(t *testing.T) {
-	defer logtesting.ClearAll()
 	ctx, cancel, informers := SetupFakeContextWithCancel(t)
 
 	configMapWatcher := configmap.NewStaticWatcher(&corev1.ConfigMap{
@@ -104,6 +103,9 @@ func TestNewConfigurationCallsSyncHandler(t *testing.T) {
 		if err := eg.Wait(); err != nil {
 			t.Fatalf("Error running controller: %v", err)
 		}
+		// To let the informers shut down.
+		time.Sleep(3 * time.Second)
+		logtesting.ClearAll()
 	}()
 
 	servingClient := fakeservingclient.Get(ctx)
diff --git a/pkg/reconciler/nscert/nscert_test.go b/pkg/reconciler/nscert/nscert_test.go
index f738fd4253e1..d222e0b3aabb 100644
--- a/pkg/reconciler/nscert/nscert_test.go
+++ b/pkg/reconciler/nscert/nscert_test.go
@@ -20,6 +20,7 @@ import (
 	"context"
 	"fmt"
 	"testing"
+	"time"
 
 	"github.com/google/go-cmp/cmp"
 	"github.com/google/go-cmp/cmp/cmpopts"
@@ -59,12 +60,13 @@ var (
 
 func newTestSetup(t *testing.T, configs ...*corev1.ConfigMap) (
 	ctx context.Context,
+	cancel context.CancelFunc,
 	informers []controller.Informer,
 	controller *ctrl.Impl,
 	rclr *reconciler,
 	configMapWatcher *configmap.ManualWatcher) {
 
-	ctx, informers = SetupFakeContext(t)
+	ctx, cancel, informers = SetupFakeContextWithCancel(t)
 	configMapWatcher = &configmap.ManualWatcher{Namespace: system.Namespace()}
 
 	controller = NewController(ctx, configMapWatcher)
@@ -191,8 +193,12 @@ func TestReconcile(t *testing.T) {
 }
 
 func TestUpdateDomainTemplate(t *testing.T) {
-	defer ClearAll()
-	ctx, _, _, reconciler, watcher := newTestSetup(t)
+	ctx, cancel, _, _, reconciler, watcher := newTestSetup(t)
+	defer func() {
+		cancel()
+		time.Sleep(3 * time.Second)
+		ClearAll()
+	}()
 
 	sorter := cmpopts.SortSlices(func(a, b string) bool {
 		return a < b
@@ -303,7 +309,12 @@ func TestDomainConfigDefaultDomain(t *testing.T) {
 			"other.com": "selector:\n app: dev",
 		},
 	}
-	ctx, _, _, reconciler, _ := newTestSetup(t, domCfg)
+	ctx, cancel, _, _, reconciler, _ := newTestSetup(t, domCfg)
+	defer func() {
+		cancel()
+		time.Sleep(3 * time.Second)
+		ClearAll()
+	}()
 
 	ns := kubeNamespace("testns")
 	nsInformer := fakeinformerfactory.Get(ctx).Core().V1().Namespaces()
@@ -336,7 +347,12 @@ func TestDomainConfigExplicitDefaultDomain(t *testing.T) {
 			"default.com": "",
 		},
 	}
-	ctx, _, _, reconciler, _ := newTestSetup(t, domCfg)
+	ctx, cancel, _, _, reconciler, _ := newTestSetup(t, domCfg)
+	defer func() {
+		cancel()
+		time.Sleep(3 * time.Second)
+		ClearAll()
+	}()
 
 	namespace := kubeNamespace("testns")
 	nsInformer := fakeinformerfactory.Get(ctx).Core().V1().Namespaces()
diff --git a/pkg/reconciler/revision/revision_test.go b/pkg/reconciler/revision/revision_test.go
index 0db3b96bb0d6..13f95e1d6529 100644
--- a/pkg/reconciler/revision/revision_test.go
+++ b/pkg/reconciler/revision/revision_test.go
@@ -271,7 +271,10 @@ func (r *errorResolver) Resolve(_ string, _ k8schain.Options, _ sets.String) (st
 
 func TestResolutionFailed(t *testing.T) {
 	ctx, cancel, _, controller, _ := newTestController(t)
-	defer cancel()
+	defer func() {
+		cancel()
+		time.Sleep(3 * time.Second)
+	}()
 
 	// Unconditionally return this error during resolution.
 	errorMessage := "I am the expected error message, hear me ROAR!"
@@ -568,6 +571,8 @@ func TestGlobalResyncOnConfigMapUpdateRevision(t *testing.T) {
 				if err := grp.Wait(); err != nil {
 					t.Errorf("Wait() = %v", err)
 				}
+				// To allow all the informers shut down.
+				time.Sleep(3 * time.Second)
 			}()
 
 			servingClient := fakeservingclient.Get(ctx)
@@ -722,6 +727,8 @@ func TestGlobalResyncOnConfigMapUpdateDeployment(t *testing.T) {
 				if err := grp.Wait(); err != nil {
 					t.Errorf("Wait() = %v", err)
 				}
+				// To allow all the informers shut down.
+				time.Sleep(3 * time.Second)
 			}()
 
 			kubeClient := fakekubeclient.Get(ctx)