enhance: Add unittest for config.EventDispatcher (#28552)

These is no enough unittest case for EventDispatcher, see also #28540. 
This PR add unit test case for all methods for EventDispatcher
Related to #28538

Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>

pkg/config/event_dispatcher_test.go

@@ -0,0 +1,141 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package config
+
+import (
+	"testing"
+
+	"github.com/samber/lo"
+	"github.com/stretchr/testify/suite"
+	"go.uber.org/atomic"
+)
+
+type EventDispatcherSuite struct {
+	suite.Suite
+
+	dispatcher *EventDispatcher
+}
+
+func (s *EventDispatcherSuite) SetupTest() {
+	s.dispatcher = NewEventDispatcher()
+}
+
+func (s *EventDispatcherSuite) TestRegister() {
+	dispatcher := s.dispatcher
+
+	s.Run("test_register_same_key", func() {
+		dispatcher.Register("a", NewHandler("handler_1", func(*Event) {}))
+		dispatcher.Register("a", NewHandler("handler_2", func(*Event) {}))
+
+		handlers := dispatcher.Get("a")
+		s.ElementsMatch([]string{"handler_1", "handler_2"}, lo.Map(handlers, func(h EventHandler, _ int) string { return h.GetIdentifier() }))
+	})
+
+	s.Run("test_register_same_id", func() {
+		dispatcher.Register("b", NewHandler("handler_1", func(*Event) {}))
+		dispatcher.Register("b", NewHandler("handler_1", func(*Event) {}))
+
+		handlers := dispatcher.Get("b")
+		s.ElementsMatch([]string{"handler_1", "handler_1"}, lo.Map(handlers, func(h EventHandler, _ int) string { return h.GetIdentifier() }))
+	})
+}
+
+func (s *EventDispatcherSuite) TestRegisterForKeyPrefix() {
+	dispatcher := s.dispatcher
+
+	s.Run("test_register_same_key", func() {
+		dispatcher.RegisterForKeyPrefix("a", NewHandler("handler_1", func(*Event) {}))
+		dispatcher.RegisterForKeyPrefix("a", NewHandler("handler_2", func(*Event) {}))
+
+		handlers := dispatcher.Get("a")
+		s.ElementsMatch([]string{"handler_1", "handler_2"}, lo.Map(handlers, func(h EventHandler, _ int) string { return h.GetIdentifier() }))
+		s.Contains(dispatcher.keyPrefix, "a")
+	})
+
+	s.Run("test_register_same_id", func() {
+		dispatcher.RegisterForKeyPrefix("b", NewHandler("handler_1", func(*Event) {}))
+		dispatcher.RegisterForKeyPrefix("b", NewHandler("handler_1", func(*Event) {}))
+
+		handlers := dispatcher.Get("b")
+		s.ElementsMatch([]string{"handler_1", "handler_1"}, lo.Map(handlers, func(h EventHandler, _ int) string { return h.GetIdentifier() }))
+		s.Contains(dispatcher.keyPrefix, "b")
+	})
+}
+
+func (s *EventDispatcherSuite) TestUnregister() {
+	dispatcher := s.dispatcher
+
+	s.Run("unregister_non_exist_key", func() {
+		s.NotPanics(func() {
+			dispatcher.Unregister("non_register", NewHandler("handler_1", func(*Event) {}))
+		})
+	})
+
+	s.Run("unregister_non_exist_id", func() {
+		dispatcher.Register("b", NewHandler("handler_1", func(*Event) {}))
+
+		s.NotPanics(func() {
+			dispatcher.Unregister("b", NewHandler("handler_2", func(*Event) {}))
+		})
+
+		handlers := dispatcher.Get("b")
+		s.ElementsMatch([]string{"handler_1"}, lo.Map(handlers, func(h EventHandler, _ int) string { return h.GetIdentifier() }))
+	})
+
+	s.Run("unregister_exist_handler", func() {
+		dispatcher.Register("c", NewHandler("handler_1", func(*Event) {}))
+
+		s.NotPanics(func() {
+			dispatcher.Unregister("c", NewHandler("handler_1", func(*Event) {}))
+		})
+
+		handlers := dispatcher.Get("c")
+		s.ElementsMatch([]string{}, lo.Map(handlers, func(h EventHandler, _ int) string { return h.GetIdentifier() }))
+	})
+}
+
+func (s *EventDispatcherSuite) TestDispatch() {
+	dispatcher := s.dispatcher
+
+	s.Run("dispatch_key_event", func() {
+		called := atomic.NewBool(false)
+
+		dispatcher.Register("a", NewHandler("handler_1", func(*Event) { called.Store(true) }))
+
+		dispatcher.Dispatch(newEvent("test", "test", "aa", "b"))
+
+		s.False(called.Load())
+
+		dispatcher.Dispatch(newEvent("test", "test", "a", "b"))
+
+		s.True(called.Load())
+	})
+
+	s.Run("dispatch_prefix_event", func() {
+		called := atomic.NewBool(false)
+
+		dispatcher.RegisterForKeyPrefix("b", NewHandler("handler_1", func(*Event) { called.Store(true) }))
+
+		dispatcher.Dispatch(newEvent("test", "test", "bb", "b"))
+
+		s.True(called.Load())
+	})
+}
+
+func TestEventDispatcher(t *testing.T) {
+	suite.Run(t, new(EventDispatcherSuite))
+}