diff --git a/service/fcm/fcm.go b/service/fcm/fcm.go
index 098dedb..a4f168f 100644
--- a/service/fcm/fcm.go
+++ b/service/fcm/fcm.go
@@ -23,6 +23,8 @@ type (
 )
 
 // fcmClient abstracts go-fcm for writing unit tests
+//
+//go:generate mockery --name=fcmClient --output=. --case=underscore --inpackage
 type fcmClient interface {
 	SendWithRetry(*fcm.Message, int) (*fcm.Response, error)
 }
diff --git a/service/fcm/fcm_test.go b/service/fcm/fcm_test.go
index 971f045..7063d45 100644
--- a/service/fcm/fcm_test.go
+++ b/service/fcm/fcm_test.go
@@ -9,7 +9,17 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func TestAddReceivers(t *testing.T) {
+func TestFCM_New(t *testing.T) {
+	t.Parallel()
+
+	assert := require.New(t)
+
+	service, err := New("server-api-key")
+	assert.NotNil(service)
+	assert.Nil(err)
+}
+
+func TestFCM_AddReceivers(t *testing.T) {
 	t.Parallel()
 
 	assert := require.New(t)
@@ -23,7 +33,7 @@ func TestAddReceivers(t *testing.T) {
 	assert.Equal(svc.deviceTokens, deviceTokens)
 }
 
-func TestSend(t *testing.T) {
+func TestFCM_Send(t *testing.T) {
 	t.Parallel()
 
 	assert := require.New(t)
@@ -38,7 +48,7 @@ func TestSend(t *testing.T) {
 	}
 
 	// test fcm client send
-	mockClient := newMockFCMClient(t)
+	mockClient := newMockFcmClient(t)
 	mockClient.On("SendWithRetry", &fcm.Message{
 		To: mockToken,
 		Notification: &fcm.Notification{
@@ -54,7 +64,7 @@ func TestSend(t *testing.T) {
 	mockClient.AssertExpectations(t)
 
 	// test fcm client send with data
-	mockClient = newMockFCMClient(t)
+	mockClient = newMockFcmClient(t)
 	mockClient.On("SendWithRetry", &fcm.Message{
 		To:   mockToken,
 		Data: mockData,
@@ -72,7 +82,7 @@ func TestSend(t *testing.T) {
 	mockClient.AssertExpectations(t)
 
 	// test fcm client send with data and retries
-	mockClient = newMockFCMClient(t)
+	mockClient = newMockFcmClient(t)
 	mockClient.On("SendWithRetry", &fcm.Message{
 		To:   mockToken,
 		Data: mockData,
@@ -91,7 +101,7 @@ func TestSend(t *testing.T) {
 	mockClient.AssertExpectations(t)
 
 	// test fcm client returning error
-	mockClient = newMockFCMClient(t)
+	mockClient = newMockFcmClient(t)
 	mockClient.On("SendWithRetry", &fcm.Message{
 		To:   mockToken,
 		Data: mockData,
@@ -111,7 +121,7 @@ func TestSend(t *testing.T) {
 
 	// test fcm client multiple receivers
 	anotherMockToken := "another_device_token"
-	mockClient = newMockFCMClient(t)
+	mockClient = newMockFcmClient(t)
 	mockClient.On("SendWithRetry", &fcm.Message{
 		To:   mockToken,
 		Data: mockData,
@@ -138,7 +148,7 @@ func TestSend(t *testing.T) {
 	mockClient.AssertExpectations(t)
 }
 
-func TestGetMessageData(t *testing.T) {
+func TestFCM_GetMessageData(t *testing.T) {
 	t.Parallel()
 
 	assert := require.New(t)
@@ -179,7 +189,7 @@ func TestGetMessageData(t *testing.T) {
 	assert.True(ok)
 }
 
-func TestGetMessageRetryAttempts(t *testing.T) {
+func TestFCM_GetMessageRetryAttempts(t *testing.T) {
 	t.Parallel()
 
 	assert := require.New(t)
diff --git a/service/fcm/mock_fcmClient.go b/service/fcm/mock_fcmClient.go
deleted file mode 100644
index 78996da..0000000
--- a/service/fcm/mock_fcmClient.go
+++ /dev/null
@@ -1,48 +0,0 @@
-// Code generated by mockery v2.12.2. DO NOT EDIT.
-
-package fcm
-
-import (
-	testing "testing"
-
-	fcm "github.com/appleboy/go-fcm"
-	mock "github.com/stretchr/testify/mock"
-)
-
-// mockFCMClient is an autogenerated mock type for the mockFCMClient type
-type mockFCMClient struct {
-	mock.Mock
-}
-
-// SendWithRetry provides a mock function with given fields: _a0, _a1
-func (_m *mockFCMClient) SendWithRetry(_a0 *fcm.Message, _a1 int) (*fcm.Response, error) {
-	ret := _m.Called(_a0, _a1)
-
-	var r0 *fcm.Response
-	if rf, ok := ret.Get(0).(func(*fcm.Message, int) *fcm.Response); ok {
-		r0 = rf(_a0, _a1)
-	} else {
-		if ret.Get(0) != nil {
-			r0 = ret.Get(0).(*fcm.Response)
-		}
-	}
-
-	var r1 error
-	if rf, ok := ret.Get(1).(func(*fcm.Message, int) error); ok {
-		r1 = rf(_a0, _a1)
-	} else {
-		r1 = ret.Error(1)
-	}
-
-	return r0, r1
-}
-
-// newMockFCMClient creates a new instance of mockFCMClient. It also registers the testing.TB interface on the mock and a cleanup function to assert the mocks expectations.
-func newMockFCMClient(t testing.TB) *mockFCMClient {
-	mock := &mockFCMClient{}
-	mock.Mock.Test(t)
-
-	t.Cleanup(func() { mock.AssertExpectations(t) })
-
-	return mock
-}
diff --git a/service/fcm/mock_fcm_client.go b/service/fcm/mock_fcm_client.go
new file mode 100644
index 0000000..7795a6a
--- /dev/null
+++ b/service/fcm/mock_fcm_client.go
@@ -0,0 +1,51 @@
+// Code generated by mockery v2.14.0. DO NOT EDIT.
+
+package fcm
+
+import (
+	go_fcm "github.com/appleboy/go-fcm"
+	mock "github.com/stretchr/testify/mock"
+)
+
+// mockFcmClient is an autogenerated mock type for the fcmClient type
+type mockFcmClient struct {
+	mock.Mock
+}
+
+// SendWithRetry provides a mock function with given fields: _a0, _a1
+func (_m *mockFcmClient) SendWithRetry(_a0 *go_fcm.Message, _a1 int) (*go_fcm.Response, error) {
+	ret := _m.Called(_a0, _a1)
+
+	var r0 *go_fcm.Response
+	if rf, ok := ret.Get(0).(func(*go_fcm.Message, int) *go_fcm.Response); ok {
+		r0 = rf(_a0, _a1)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).(*go_fcm.Response)
+		}
+	}
+
+	var r1 error
+	if rf, ok := ret.Get(1).(func(*go_fcm.Message, int) error); ok {
+		r1 = rf(_a0, _a1)
+	} else {
+		r1 = ret.Error(1)
+	}
+
+	return r0, r1
+}
+
+type mockConstructorTestingTnewMockFcmClient interface {
+	mock.TestingT
+	Cleanup(func())
+}
+
+// newMockFcmClient creates a new instance of mockFcmClient. It also registers a testing interface on the mock and a cleanup function to assert the mocks expectations.
+func newMockFcmClient(t mockConstructorTestingTnewMockFcmClient) *mockFcmClient {
+	mock := &mockFcmClient{}
+	mock.Mock.Test(t)
+
+	t.Cleanup(func() { mock.AssertExpectations(t) })
+
+	return mock
+}