remove unnecessary dependencies between plugins

remove unnecessary dependencies between plugins
upgrade go-micro.dev/v4 to v4.2.1

broker/memory_test.go

@@ -0,0 +1,50 @@
+package broker_test
+
+import (
+	"fmt"
+	"testing"
+
+	"go-micro.dev/v4/broker"
+)
+
+func TestMemoryBroker(t *testing.T) {
+	b := broker.NewMemoryBroker()
+
+	if err := b.Connect(); err != nil {
+		t.Fatalf("Unexpected connect error %v", err)
+	}
+
+	topic := "test"
+	count := 10
+
+	fn := func(p broker.Event) error {
+		return nil
+	}
+
+	sub, err := b.Subscribe(topic, fn)
+	if err != nil {
+		t.Fatalf("Unexpected error subscribing %v", err)
+	}
+
+	for i := 0; i < count; i++ {
+		message := &broker.Message{
+			Header: map[string]string{
+				"foo": "bar",
+				"id":  fmt.Sprintf("%d", i),
+			},
+			Body: []byte(`hello world`),
+		}
+
+		if err := b.Publish(topic, message); err != nil {
+			t.Fatalf("Unexpected error publishing %d", i)
+		}
+	}
+
+	if err := sub.Unsubscribe(); err != nil {
+		t.Fatalf("Unexpected error unsubscribing from %s: %v", topic, err)
+	}
+
+	if err := b.Disconnect(); err != nil {
+		t.Fatalf("Unexpected connect error %v", err)
+	}
+}