Fix unit test flaky for IPsec controller (#4016)

Wait one second as the fake clientset doesn't support watching with specific resourceVersion.
Otherwise the update event would be missed by the watcher used in csrutil.WaitForCertificate()
if it happens to be generated in-between the List and Watch calls.

Fixes: #3851

Signed-off-by: Xu Liu <xliu2@vmware.com>

pkg/agent/controller/ipseccertificate/ipsec_certificate_controller_test.go

@@ -353,6 +353,12 @@ func signCSR(t *testing.T, controller *fakeController,
 	assert.Empty(t, remain)
 	req, err := x509.ParseCertificateRequest(block.Bytes)
 	assert.NoError(t, err)
+
+	// Wait one second as the fake clientset doesn't support watching with specific resourceVersion.
+	// Otherwise the update event would be missed by the watcher used in csrutil.WaitForCertificate()
+	// if it happens to be generated in-between the List and Watch calls.
+	time.Sleep(1 * time.Second)
+
 	newCert := createCertificate(t, req.Subject.CommonName, controller.caCert,
 		controller.caKey, req.PublicKey, csr.CreationTimestamp.Time, expirationDuration)
 	toUpdate := csr.DeepCopy()
@@ -369,6 +375,7 @@ func signCSR(t *testing.T, controller *fakeController,
 	_, err = controller.kubeClient.CertificatesV1().CertificateSigningRequests().
 		UpdateStatus(context.TODO(), toUpdate, metav1.UpdateOptions{})
 	assert.NoError(t, err)
+	t.Logf("Sign CSR %q successfully", csr.Name)
 }
 
 func Test_jitteryDuration(t *testing.T) {