All controller unit tests should not cancel context until test is over

All controller unit tests were accidentally using a timeout context
for the informers, instead of a cancel context which stays alive until
each test is completely finished. There is no reason to risk
unpredictable behavior of a timeout being reached during an individual
test, even though with the previous 3 second timeout it could only be
reached on a machine which is running orders of magnitude slower than
usual, since each test usually runs in about 100-300 ms. Unfortunately,
sometimes our CI workers might get that slow.

This sparked a review of other usages of timeout contexts in other
tests, and all of them were increased to a minimum value of 1 minute,
under the rule of thumb that our tests will be more reliable on slow
machines if they "pass fast and fail slow".

internal/controller/authenticator/webhookcachefiller/webhookcachefiller_test.go

@@ -11,7 +11,6 @@ import (
 	"net/http"
 	"os"
 	"testing"
-	"time"
 
 	"github.com/stretchr/testify/require"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -93,7 +92,7 @@ func TestController(t *testing.T) {
 
 			controller := New(cache, informers.Authentication().V1alpha1().WebhookAuthenticators(), testLog)
 
-			ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+			ctx, cancel := context.WithCancel(context.Background())
 			defer cancel()
 
 			informers.Start(ctx.Done())