Merge pull request kubernetes#53519 from m1093782566/more-fakes

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

implement fakeIPVS update virtual server

**What this PR does / why we need it**:

* Implement UpdateVirtualServer() for FakeIPVS because ipvs/proxier needs it.

* Add UTs - Since there are some real logics in fakeIPVS interface, it's important to add some UTs which can help avoiding some mistakes.

**Which issue this PR fixes**: fixes kubernetes#53518

**Special notes for your reviewer**:

**Release note**:

```release-note
NONE
```

Author: Kubernetes Submit Queue

pkg/util/ipvs/testing/fake.go

@@ -77,11 +77,13 @@ func (f *FakeIPVS) AddVirtualServer(serv *utilipvs.VirtualServer) error {
 	return nil
 }
 
-//UpdateVirtualServer is an empty implementation
+//UpdateVirtualServer is a fake implementation, it updates the VirtualServer in the cache store.
 func (f *FakeIPVS) UpdateVirtualServer(serv *utilipvs.VirtualServer) error {
 	if serv == nil {
 		return fmt.Errorf("Failed to update service, service can't be nil")
 	}
+	key := toServiceKey(serv)
+	f.Services[key] = serv
 	return nil
 }
 

pkg/util/ipvs/testing/fake_test.go

@@ -31,6 +31,7 @@ func TestVirtualServer(t *testing.T) {
 		Address:  net.ParseIP("1.2.3.4"),
 		Port:     uint16(80),
 		Protocol: string("TCP"),
+		Flags:    utilipvs.FlagHashed,
 	}
 	err := fake.AddVirtualServer(vs1)
 	if err != nil {
@@ -44,6 +45,22 @@ func TestVirtualServer(t *testing.T) {
 	if !vs1.Equal(got1) {
 		t.Errorf("Expect virtual server: %v, got: %v", vs1, got1)
 	}
+	// Update virtual server
+	vs12 := &utilipvs.VirtualServer{
+		Address:  net.ParseIP("1.2.3.4"),
+		Port:     uint16(80),
+		Protocol: string("TCP"),
+		Flags:    utilipvs.FlagPersistent,
+	}
+	err = fake.UpdateVirtualServer(vs12)
+	if err != nil {
+		t.Errorf("Fail to update virutal server, error: %v", err)
+	}
+	// Check the updated virtual server
+	got12, err := fake.GetVirtualServer(vs1)
+	if !got12.Equal(vs12) {
+		t.Errorf("Expect virutal server: %v, got: %v", vs12, got12)
+	}
 	// Add another virtual server
 	vs2 := &utilipvs.VirtualServer{
 		Address:  net.ParseIP("10::40"),