add ut

go.mod

@@ -276,6 +276,7 @@ require (
 )
 
 require (
+	bou.ke/monkey v1.0.2
 	github.com/Azure/azure-container-networking/zapai v0.0.3
 	github.com/Azure/azure-sdk-for-go v68.0.0+incompatible
 	github.com/Azure/azure-sdk-for-go/sdk/azcore v1.17.0

go.sum

@@ -1,3 +1,5 @@
+bou.ke/monkey v1.0.2 h1:kWcnsrCNUatbxncxR/ThdYqbytgOIArtYWqcQLQzKLI=
+bou.ke/monkey v1.0.2/go.mod h1:OqickVX3tNx6t33n1xvtTtu85YN5s6cKwVug+oHMaIA=
 cel.dev/expr v0.15.0 h1:O1jzfJCQBfL5BFoYktaxwIhuttaQPsVWerH9/EEKx0w=
 cel.dev/expr v0.15.0/go.mod h1:TRSuuV7DlVCE/uwv5QbAiW/v8l5O8C4eEPHeu7gf7Sg=
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=

pkg/watchers/endpoint/types.go

@@ -29,16 +29,6 @@ func NewWatcher() *Watcher {
 	return w
 }
 
-type key struct {
-	name         string
-	hardwareAddr string
-	// Network namespace for linux.
-	// Compartment ID for windows.
-	netNsID int
-}
-
-type cache map[key]interface{}
-
 type EndpointEvent struct {
 	// Type is the type of the event.
 	Type EventType
@@ -70,11 +60,3 @@ func (e EventType) String() string {
 		return "unknown"
 	}
 }
-
-func (c cache) deepcopy() cache {
-	copy := make(cache)
-	for k, v := range c {
-		copy[k] = v
-	}
-	return copy
-}

pkg/watchers/endpoint/watcher_test.go

@@ -0,0 +1,86 @@
+package endpoint
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"bou.ke/monkey"
+	"github.com/microsoft/retina/pkg/log"
+	"github.com/stretchr/testify/require"
+	"github.com/vishvananda/netlink"
+	"golang.org/x/sys/unix"
+)
+
+func TestName(t *testing.T) {
+	_, err := log.SetupZapLogger(log.GetDefaultLogOpts())
+	require.NoError(t, err)
+	w := NewWatcher()
+	require.Equal(t, watcherName, w.Name())
+}
+
+func TestStart(t *testing.T) {
+	// Monkey patch netlink.LinkSubscribeWithOptions with our fakeLinkSubscribe function to simulate netlink events.
+	// TIL: https://bou.ke/blog/monkey-patching-in-go/
+	// Should be fine for testing purposes (?)
+	patch := monkey.Patch(netlink.LinkSubscribeWithOptions, fakeLinkSubscribe)
+	defer patch.Unpatch()
+
+	_, err := log.SetupZapLogger(log.GetDefaultLogOpts())
+	require.NoError(t, err)
+
+	w := NewWatcher()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	doneCh := make(chan error, 1)
+	go func() {
+		doneCh <- w.Start(ctx)
+	}()
+
+	// Wait briefly to allow the fake event to be sent.
+	time.Sleep(50 * time.Millisecond)
+
+	// Cancel the context to stop the watcher.
+	cancel()
+
+	// Wait for Start to finish.
+	err = <-doneCh
+	require.NoError(t, err, "Start should exit without error")
+}
+
+// fakeLinkSubscribe simulates netlink events by sending a fake event after a short delay.
+func fakeLinkSubscribe(netlinkEvCh chan<- netlink.LinkUpdate, done <-chan struct{}, _ netlink.LinkSubscribeOptions) error {
+	go func() {
+		time.Sleep(10 * time.Millisecond)
+		fakeVethCreatedEvent := netlink.LinkUpdate{
+			Header: unix.NlMsghdr{
+				Type: unix.RTM_NEWLINK,
+			},
+			Link: &netlink.Veth{
+				LinkAttrs: netlink.LinkAttrs{
+					Name:      "veth0",
+					Index:     1,
+					OperState: netlink.OperUp,
+				},
+			},
+		}
+		netlinkEvCh <- fakeVethCreatedEvent
+		fakeVethDeletedEvent := netlink.LinkUpdate{
+			Header: unix.NlMsghdr{
+				Type: unix.RTM_DELLINK,
+			},
+			Link: &netlink.Veth{
+				LinkAttrs: netlink.LinkAttrs{
+					Name:      "veth0",
+					Index:     1,
+					OperState: netlink.OperDown,
+				},
+			},
+		}
+		netlinkEvCh <- fakeVethDeletedEvent
+		<-done
+	}()
+	return nil
+}