Add unit tests for common.go in pkg/util

Signed-off-by: Nishant Bansal <[email protected]>

pkg/util/common_test.go

@@ -69,8 +69,22 @@ func TestDiffKey(t *testing.T) {
 			t.Errorf("removed = %v, want []string{\"kubefed\"}", removed)
 		}
 	})
+	t.Run("no old, no new", func(t *testing.T) {
+		var previous map[string]sigMultiCluster = nil
+		var current map[string]string = nil
+		added, removed := DiffKey(previous, current)
+		if len(added) != 0 && len(removed) != 0 {
+			t.Errorf("added = %v want nil, removed = %v want nil", added, removed)
+		}
+		if len(added) != 0 {
+			t.Errorf("added = %v, want nil", added)
+		}
+		if len(removed) != 0 {
+			t.Errorf("removed = %v, want nil", removed)
+		}
+	})
 	t.Run("no old, all new added", func(t *testing.T) {
-		previous := map[string]sigMultiCluster{}
+		var previous map[string]sigMultiCluster = nil
 		current := map[string]string{
 			"karmada": "v1.6.0",
 		}
@@ -82,6 +96,19 @@ func TestDiffKey(t *testing.T) {
 			t.Errorf("removed = %v, want nil", removed)
 		}
 	})
+	t.Run("all old removed, no new", func(t *testing.T) {
+		previous := map[string]sigMultiCluster{
+			"kubefed": kubefed,
+		}
+		var current map[string]string = nil
+		added, removed := DiffKey(previous, current)
+		if len(added) != 0 {
+			t.Errorf("added = %v, want nil", added)
+		}
+		if len(removed) != 1 || removed[0] != "kubefed" {
+			t.Errorf("removed = %v, want []string{\"kubefed\"}", removed)
+		}
+	})
 	t.Run("removed, added and remained", func(t *testing.T) {
 		previous := map[string]sigMultiCluster{
 			"kubefed":         kubefed,
@@ -111,15 +138,26 @@ func TestStringerJoin(t *testing.T) {
 }
 
 func TestKeys(t *testing.T) {
-	mcs := map[string]sigMultiCluster{
-		kubefed.Name: kubefed,
-		karmada.Name: karmada,
-	}
-	got := Keys(mcs)
-	expect := []string{kubefed.Name, karmada.Name}
-	sort.Strings(got)
-	sort.Strings(expect)
-	if !reflect.DeepEqual(got, expect) {
-		t.Errorf("got = %v, want %v", got, expect)
-	}
+	t.Run("keys exist", func(t *testing.T) {
+		mcs := map[string]sigMultiCluster{
+			kubefed.Name: kubefed,
+			karmada.Name: karmada,
+		}
+		got := Keys(mcs)
+		expect := []string{kubefed.Name, karmada.Name}
+		sort.Strings(got)
+		sort.Strings(expect)
+		if !reflect.DeepEqual(got, expect) {
+			t.Errorf("got = %v, want %v", got, expect)
+		}
+	})
+	t.Run("empty keys", func(t *testing.T) {
+		var mcs map[string]sigMultiCluster = nil
+		got := Keys(mcs)
+		var expect []string = nil
+		sort.Strings(got)
+		if !reflect.DeepEqual(got, expect) {
+			t.Errorf("got = %v, want %v", got, expect)
+		}
+	})
 }