Implemented unit test for PUBSUB NUMSUB command handler

src/modules/pubsub/commands_test.go

@@ -715,10 +715,124 @@ func Test_HandleNumPat(t *testing.T) {
 	}()
 
 	select {
-	case <-time.After(300 * time.Millisecond):
+	case <-time.After(200 * time.Millisecond):
 		t.Error("timeout")
 	case <-done:
 	}
 }
 
-func Test_HandleNumSub(t *testing.T) {}
+func Test_HandleNumSub(t *testing.T) {
+	done := make(chan struct{})
+	go func() {
+		// Create separate mock server for this test
+		var port uint16 = 7591
+		pubsub = NewPubSub()
+		mockServer := server.NewServer(server.Opts{
+			PubSub:   pubsub,
+			Commands: Commands(),
+			Config: utils.Config{
+				BindAddr:       bindAddr,
+				Port:           port,
+				DataDir:        "",
+				EvictionPolicy: utils.NoEviction,
+			},
+		})
+
+		ctx := context.WithValue(context.Background(), "test_name", "PUBSUB NUMSUB")
+
+		channels := []string{"channel_1", "channel_2", "channel_3"}
+		connections := make([]struct {
+			w *net.Conn
+			r *resp.Conn
+		}, 3)
+		for i := 0; i < len(connections); i++ {
+			w, r := net.Pipe()
+			connections[i] = struct {
+				w *net.Conn
+				r *resp.Conn
+			}{w: &w, r: resp.NewConn(r)}
+			go func() {
+				if _, err := handleSubscribe(ctx, append([]string{"SUBSCRIBE"}, channels...), mockServer, &w); err != nil {
+					t.Error(err)
+				}
+			}()
+			for j := 0; j < len(channels); j++ {
+				v, _, err := connections[i].r.ReadValue()
+				if err != nil {
+					t.Error(err)
+				}
+				arr := v.Array()
+				if !slices.ContainsFunc(channels, func(s string) bool {
+					return s == arr[1].String()
+				}) {
+					t.Errorf("found unexpected pattern in response \"%s\"", arr[1].String())
+				}
+			}
+		}
+
+		tests := []struct {
+			cmd              []string
+			expectedResponse [][]string
+		}{
+			{ // 1. Get all subscriptions on existing channels
+				cmd:              append([]string{"PUBSUB", "NUMSUB"}, channels...),
+				expectedResponse: [][]string{{"channel_1", "3"}, {"channel_2", "3"}, {"channel_3", "3"}},
+			},
+			{ // 2. Get all the subscriptions of on existing channels and a few non-existent ones
+				cmd: append([]string{"PUBSUB", "NUMSUB", "non_existent_channel_1", "non_existent_channel_2"}, channels...),
+				expectedResponse: [][]string{
+					{"non_existent_channel_1", "0"},
+					{"non_existent_channel_2", "0"},
+					{"channel_1", "3"},
+					{"channel_2", "3"},
+					{"channel_3", "3"},
+				},
+			},
+			{ // 3. Get an empty array when channels are not provided in the command
+				cmd:              []string{"PUBSUB", "NUMSUB"},
+				expectedResponse: make([][]string, 0),
+			},
+		}
+
+		for i, test := range tests {
+			ctx = context.WithValue(ctx, "test_index", i)
+
+			res, err := handlePubSubNumSubs(ctx, test.cmd, mockServer, nil)
+			if err != nil {
+				t.Error(err)
+			}
+
+			rd := resp.NewReader(bytes.NewReader(res))
+			rv, _, err := rd.ReadValue()
+			if err != nil {
+				t.Error(err)
+			}
+
+			arr := rv.Array()
+			if len(arr) != len(test.expectedResponse) {
+				t.Errorf("expected response array of length %d, got %d", len(test.expectedResponse), len(arr))
+			}
+
+			for _, item := range arr {
+				itemArr := item.Array()
+				if len(itemArr) != 2 {
+					t.Errorf("expected each response item to be of length 2, got %d", len(itemArr))
+				}
+				if !slices.ContainsFunc(test.expectedResponse, func(expected []string) bool {
+					return expected[0] == itemArr[0].String() && expected[1] == itemArr[1].String()
+				}) {
+					t.Errorf("could not find entry with channel \"%s\", with %d subscribers in expected response",
+						itemArr[0].String(), itemArr[1].Integer())
+				}
+			}
+		}
+
+		done <- struct{}{}
+	}()
+
+	select {
+	case <-time.After(200 * time.Millisecond):
+		t.Error("timeout")
+	case <-done:
+	}
+}