mock := mock.NewMockClusterAdmin()
mock.On("ListTopics").Return(initialKafkaTopics, nil).Once()

package consumer

import (
"errors"
"github.com/Shopify/sarama"
"github.com/stretchr/testify/assert"
"kafka-azure-sink/src/internal/mock"
"slices"
"testing"
)

func TestSuccessAdditionOfKafkaTopics(t *testing.T) {

    baseTopics := []string{"ncyd_kubernetes", "etlflow_*"}
    kafkaTopics := []string{"ncyd_test1", "etlflow_ssh", "etlflow_nrd"}

    initialKafkaTopics := buildTopicMap(kafkaTopics)

    mock := mock.NewMockClusterAdmin()
    mock.On("ListTopics").Return(initialKafkaTopics, nil).Once()

    topicManager, err := NewTopicManager(mock, baseTopics, 1)
    assert.Nil(t, err)

    topics := topicManager.GetTopicList()

    assert.True(t, slices.Contains(topics,baseTopics[0]))
    assert.True(t, slices.Contains(topics,kafkaTopics[1]))
    assert.True(t, slices.Contains(topics,kafkaTopics[2]))

    //add a kafka topic
    kafkaTopics = append(kafkaTopics, "etlflow_newTopic")
    revisedKafkaTopics := buildTopicMap(kafkaTopics)
    mock.On("ListTopics").Return(revisedKafkaTopics, nil).Once()

    //scan for new topic
    newTopic, err := topicManager.scanForNewTopics()
    assert.Nil(t, err)
    assert.True(t, newTopic)
}

func TestFailureInitializationError(t *testing.T) {

    baseTopics := []string{"ncyd_kubernetes", "etlflow_*"}

    emptyMap := buildTopicMap([]string{})

    mock := mock.NewMockClusterAdmin()
    mock.On("ListTopics").Return(emptyMap, errors.New("error")).Once()

    _, err := NewTopicManager(mock, baseTopics, 1)
    assert.NotNil(t, err)
}
func buildTopicMap(kafkaTopics []string) map[string]sarama.TopicDetail {

    topicMap := make(map[string]sarama.TopicDetail)
    for _, topic := range kafkaTopics {
     tp := sarama.TopicDetail{}
     topicMap[topic] = tp
    }
    return topicMap
}
...

package mock

import (
"github.com/Shopify/sarama"
"github.com/stretchr/testify/mock"
)

type MockClusterAdmin struct{
    mock.Mock
    topics []string
}

func NewMockClusterAdmin() *MockClusterAdmin{
   mockClusterAdmin := &MockClusterAdmin{}
   return mockClusterAdmin
}

func (m *MockClusterAdmin)  ListTopics() (map[string]sarama.TopicDetail, error){

    args := m.Called()
    return args.Get(0).(map[string]sarama.TopicDetail), args.Error(1)
}
...