Refactor dependency injection (#209)

* Refactor: use func type instead of factory interface

* Refactor: remove duplicated dependencies in di.go

pkg/adaptors/certpool/cert.go

@@ -11,24 +11,19 @@ import (
 	"golang.org/x/xerrors"
 )
 
-//go:generate mockgen -destination mock_certpool/mock_certpool.go github.com/int128/kubelogin/pkg/adaptors/certpool FactoryInterface,Interface
+//go:generate mockgen -destination mock_certpool/mock_certpool.go github.com/int128/kubelogin/pkg/adaptors/certpool Interface
 
 // Set provides an implementation and interface.
 var Set = wire.NewSet(
-	wire.Struct(new(Factory), "*"),
-	wire.Bind(new(FactoryInterface), new(*Factory)),
+	wire.Value(NewFunc(New)),
 	wire.Struct(new(CertPool), "*"),
 	wire.Bind(new(Interface), new(*CertPool)),
 )
 
-type FactoryInterface interface {
-	New() Interface
-}
-
-type Factory struct{}
+type NewFunc func() Interface
 
 // New returns an instance which implements the Interface.
-func (f *Factory) New() Interface {
+func New() Interface {
 	return &CertPool{pool: x509.NewCertPool()}
 }
 

pkg/adaptors/certpool/cert_test.go

@@ -8,8 +8,7 @@ import (
 
 func TestCertPool_AddFile(t *testing.T) {
 	t.Run("Valid", func(t *testing.T) {
-		var f Factory
-		p := f.New()
+		p := New()
 		if err := p.AddFile("testdata/ca1.crt"); err != nil {
 			t.Errorf("AddFile error: %s", err)
 		}
@@ -20,8 +19,7 @@ func TestCertPool_AddFile(t *testing.T) {
 		}
 	})
 	t.Run("Invalid", func(t *testing.T) {
-		var f Factory
-		p := f.New()
+		p := New()
 		err := p.AddFile("testdata/Makefile")
 		if err == nil {
 			t.Errorf("AddFile wants an error but was nil")
@@ -30,8 +28,7 @@ func TestCertPool_AddFile(t *testing.T) {
 }
 
 func TestCertPool_AddBase64Encoded(t *testing.T) {
-	var f Factory
-	p := f.New()
+	p := New()
 	if err := p.AddBase64Encoded(readFile(t, "testdata/ca2.crt.base64")); err != nil {
 		t.Errorf("AddBase64Encoded error: %s", err)
 	}
@@ -43,8 +40,7 @@ func TestCertPool_AddBase64Encoded(t *testing.T) {
 }
 
 func TestCertPool_SetRootCAs(t *testing.T) {
-	var f Factory
-	p := f.New()
+	p := New()
 	var cfg tls.Config
 	p.SetRootCAs(&cfg)
 	if cfg.RootCAs != nil {

pkg/adaptors/certpool/mock_certpool/mock_certpool.go

@@ -1,5 +1,5 @@
 // Code generated by MockGen. DO NOT EDIT.
-// Source: github.com/int128/kubelogin/pkg/adaptors/certpool (interfaces: FactoryInterface,Interface)
+// Source: github.com/int128/kubelogin/pkg/adaptors/certpool (interfaces: Interface)
 
 // Package mock_certpool is a generated GoMock package.
 package mock_certpool
@@ -7,47 +7,9 @@ package mock_certpool
 import (
 	tls "crypto/tls"
 	gomock "github.com/golang/mock/gomock"
-	certpool "github.com/int128/kubelogin/pkg/adaptors/certpool"
 	reflect "reflect"
 )
 
-// MockFactoryInterface is a mock of FactoryInterface interface
-type MockFactoryInterface struct {
-	ctrl     *gomock.Controller
-	recorder *MockFactoryInterfaceMockRecorder
-}
-
-// MockFactoryInterfaceMockRecorder is the mock recorder for MockFactoryInterface
-type MockFactoryInterfaceMockRecorder struct {
-	mock *MockFactoryInterface
-}
-
-// NewMockFactoryInterface creates a new mock instance
-func NewMockFactoryInterface(ctrl *gomock.Controller) *MockFactoryInterface {
-	mock := &MockFactoryInterface{ctrl: ctrl}
-	mock.recorder = &MockFactoryInterfaceMockRecorder{mock}
-	return mock
-}
-
-// EXPECT returns an object that allows the caller to indicate expected use
-func (m *MockFactoryInterface) EXPECT() *MockFactoryInterfaceMockRecorder {
-	return m.recorder
-}
-
-// New mocks base method
-func (m *MockFactoryInterface) New() certpool.Interface {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "New")
-	ret0, _ := ret[0].(certpool.Interface)
-	return ret0
-}
-
-// New indicates an expected call of New
-func (mr *MockFactoryInterfaceMockRecorder) New() *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "New", reflect.TypeOf((*MockFactoryInterface)(nil).New))
-}
-
 // MockInterface is a mock of Interface interface
 type MockInterface struct {
 	ctrl     *gomock.Controller

pkg/adaptors/oidcclient/factory.go

@@ -14,9 +14,7 @@ import (
 	"golang.org/x/xerrors"
 )
 
-type FactoryInterface interface {
-	New(ctx context.Context, config Config) (Interface, error)
-}
+type NewFunc func(ctx context.Context, config Config) (Interface, error)
 
 // Config represents a configuration of OpenID Connect client.
 type Config struct {
@@ -26,14 +24,11 @@ type Config struct {
 	ExtraScopes   []string // optional
 	CertPool      certpool.Interface
 	SkipTLSVerify bool
-}
-
-type Factory struct {
-	Logger logger.Interface
+	Logger        logger.Interface
 }
 
 // New returns an instance of adaptors.Interface with the given configuration.
-func (f *Factory) New(ctx context.Context, config Config) (Interface, error) {
+func New(ctx context.Context, config Config) (Interface, error) {
 	var tlsConfig tls.Config
 	tlsConfig.InsecureSkipVerify = config.SkipTLSVerify
 	config.CertPool.SetRootCAs(&tlsConfig)
@@ -43,7 +38,7 @@ func (f *Factory) New(ctx context.Context, config Config) (Interface, error) {
 	}
 	loggingTransport := &logging.Transport{
 		Base:   baseTransport,
-		Logger: f.Logger,
+		Logger: config.Logger,
 	}
 	httpClient := &http.Client{
 		Transport: loggingTransport,
@@ -63,6 +58,6 @@ func (f *Factory) New(ctx context.Context, config Config) (Interface, error) {
 			ClientSecret: config.ClientSecret,
 			Scopes:       append(config.ExtraScopes, oidc.ScopeOpenID),
 		},
-		logger: f.Logger,
+		logger: config.Logger,
 	}, nil
 }

pkg/adaptors/oidcclient/mock_oidcclient/mock_oidcclient.go

@@ -1,5 +1,5 @@
 // Code generated by MockGen. DO NOT EDIT.
-// Source: github.com/int128/kubelogin/pkg/adaptors/oidcclient (interfaces: FactoryInterface,Interface)
+// Source: github.com/int128/kubelogin/pkg/adaptors/oidcclient (interfaces: Interface)
 
 // Package mock_oidcclient is a generated GoMock package.
 package mock_oidcclient
@@ -11,44 +11,6 @@ import (
 	reflect "reflect"
 )
 
-// MockFactoryInterface is a mock of FactoryInterface interface
-type MockFactoryInterface struct {
-	ctrl     *gomock.Controller
-	recorder *MockFactoryInterfaceMockRecorder
-}
-
-// MockFactoryInterfaceMockRecorder is the mock recorder for MockFactoryInterface
-type MockFactoryInterfaceMockRecorder struct {
-	mock *MockFactoryInterface
-}
-
-// NewMockFactoryInterface creates a new mock instance
-func NewMockFactoryInterface(ctrl *gomock.Controller) *MockFactoryInterface {
-	mock := &MockFactoryInterface{ctrl: ctrl}
-	mock.recorder = &MockFactoryInterfaceMockRecorder{mock}
-	return mock
-}
-
-// EXPECT returns an object that allows the caller to indicate expected use
-func (m *MockFactoryInterface) EXPECT() *MockFactoryInterfaceMockRecorder {
-	return m.recorder
-}
-
-// New mocks base method
-func (m *MockFactoryInterface) New(arg0 context.Context, arg1 oidcclient.Config) (oidcclient.Interface, error) {
-	m.ctrl.T.Helper()
-	ret := m.ctrl.Call(m, "New", arg0, arg1)
-	ret0, _ := ret[0].(oidcclient.Interface)
-	ret1, _ := ret[1].(error)
-	return ret0, ret1
-}
-
-// New indicates an expected call of New
-func (mr *MockFactoryInterfaceMockRecorder) New(arg0, arg1 interface{}) *gomock.Call {
-	mr.mock.ctrl.T.Helper()
-	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "New", reflect.TypeOf((*MockFactoryInterface)(nil).New), arg0, arg1)
-}
-
 // MockInterface is a mock of Interface interface
 type MockInterface struct {
 	ctrl     *gomock.Controller

pkg/adaptors/oidcclient/oidcclient.go

@@ -15,12 +15,10 @@ import (
 	"golang.org/x/xerrors"
 )
 
-//go:generate mockgen -destination mock_oidcclient/mock_oidcclient.go github.com/int128/kubelogin/pkg/adaptors/oidcclient FactoryInterface,Interface
+//go:generate mockgen -destination mock_oidcclient/mock_oidcclient.go github.com/int128/kubelogin/pkg/adaptors/oidcclient Interface
 
-// Set provides an implementation and interface for OIDC.
 var Set = wire.NewSet(
-	wire.Struct(new(Factory), "*"),
-	wire.Bind(new(FactoryInterface), new(*Factory)),
+	wire.Value(NewFunc(New)),
 )
 
 type Interface interface {

pkg/di/di.go

@@ -22,36 +22,27 @@ import (
 
 // NewCmd returns an instance of adaptors.Cmd.
 func NewCmd() cmd.Interface {
+	wire.Build(
+		NewCmdForHeadless,
+
+		// dependencies for production
+		logger.Set,
+		wire.Value(authentication.DefaultLocalServerReadyFunc),
+		credentialPluginAdaptor.Set,
+	)
+	return nil
+}
+
+// NewCmdForHeadless returns an instance of adaptors.Cmd for headless testing.
+func NewCmdForHeadless(logger.Interface, authentication.LocalServerReadyFunc, credentialPluginAdaptor.Interface) cmd.Interface {
 	wire.Build(
 		// use-cases
 		authentication.Set,
-		wire.Value(authentication.DefaultLocalServerReadyFunc),
 		standalone.Set,
 		credentialPluginUseCase.Set,
 		setup.Set,
 
 		// adaptors
-		cmd.Set,
-		env.Set,
-		kubeconfig.Set,
-		tokencache.Set,
-		credentialPluginAdaptor.Set,
-		oidcclient.Set,
-		jwtdecoder.Set,
-		certpool.Set,
-		logger.Set,
-	)
-	return nil
-}
-
-// NewCmdForHeadless returns an instance of adaptors.Cmd for headless testing.
-func NewCmdForHeadless(logger.Interface, authentication.LocalServerReadyFunc, credentialPluginAdaptor.Interface) cmd.Interface {
-	wire.Build(
-		authentication.Set,
-		standalone.Set,
-		credentialPluginUseCase.Set,
-		setup.Set,
-
 		cmd.Set,
 		env.Set,
 		kubeconfig.Set,

pkg/di/wire_gen.go

@@ -25,12 +25,20 @@ import (
 
 func NewCmd() cmd.Interface {
 	loggerInterface := logger.New()
-	factory := &oidcclient.Factory{
-		Logger: loggerInterface,
-	}
+	localServerReadyFunc := _wireLocalServerReadyFuncValue
+	interaction := &credentialplugin.Interaction{}
+	cmdInterface := NewCmdForHeadless(loggerInterface, localServerReadyFunc, interaction)
+	return cmdInterface
+}
+
+var (
+	_wireLocalServerReadyFuncValue = authentication.DefaultLocalServerReadyFunc
+)
+
+func NewCmdForHeadless(loggerInterface logger.Interface, localServerReadyFunc authentication.LocalServerReadyFunc, credentialpluginInterface credentialplugin.Interface) cmd.Interface {
+	newFunc := _wireNewFuncValue
 	decoder := &jwtdecoder.Decoder{}
 	envEnv := &env.Env{}
-	localServerReadyFunc := _wireLocalServerReadyFuncValue
 	authCode := &authentication.AuthCode{
 		Env:                  envEnv,
 		Logger:               loggerInterface,
@@ -45,35 +53,34 @@ func NewCmd() cmd.Interface {
 		Logger: loggerInterface,
 	}
 	authenticationAuthentication := &authentication.Authentication{
-		OIDCClientFactory: factory,
-		JWTDecoder:        decoder,
-		Logger:            loggerInterface,
-		Env:               envEnv,
-		AuthCode:          authCode,
-		AuthCodeKeyboard:  authCodeKeyboard,
-		ROPC:              ropc,
+		NewOIDCClient:    newFunc,
+		JWTDecoder:       decoder,
+		Logger:           loggerInterface,
+		Env:              envEnv,
+		AuthCode:         authCode,
+		AuthCodeKeyboard: authCodeKeyboard,
+		ROPC:             ropc,
 	}
 	kubeconfigKubeconfig := &kubeconfig.Kubeconfig{
 		Logger: loggerInterface,
 	}
-	certpoolFactory := &certpool.Factory{}
+	certpoolNewFunc := _wireCertpoolNewFuncValue
 	standaloneStandalone := &standalone.Standalone{
-		Authentication:  authenticationAuthentication,
-		Kubeconfig:      kubeconfigKubeconfig,
-		CertPoolFactory: certpoolFactory,
-		Logger:          loggerInterface,
+		Authentication: authenticationAuthentication,
+		Kubeconfig:     kubeconfigKubeconfig,
+		NewCertPool:    certpoolNewFunc,
+		Logger:         loggerInterface,
 	}
 	root := &cmd.Root{
 		Standalone: standaloneStandalone,
 		Logger:     loggerInterface,
 	}
 	repository := &tokencache.Repository{}
-	interaction := &credentialplugin.Interaction{}
 	getToken := &credentialplugin2.GetToken{
 		Authentication:       authenticationAuthentication,
 		TokenCacheRepository: repository,
-		CertPoolFactory:      certpoolFactory,
-		Interaction:          interaction,
+		NewCertPool:          certpoolNewFunc,
+		Interaction:          credentialpluginInterface,
 		Logger:               loggerInterface,
 	}
 	cmdGetToken := &cmd.GetToken{
@@ -81,9 +88,9 @@ func NewCmd() cmd.Interface {
 		Logger:   loggerInterface,
 	}
 	setupSetup := &setup.Setup{
-		Authentication:  authenticationAuthentication,
-		CertPoolFactory: certpoolFactory,
-		Logger:          loggerInterface,
+		Authentication: authenticationAuthentication,
+		NewCertPool:    certpoolNewFunc,
+		Logger:         loggerInterface,
 	}
 	cmdSetup := &cmd.Setup{
 		Setup: setupSetup,
@@ -98,76 +105,6 @@ func NewCmd() cmd.Interface {
 }
 
 var (
-	_wireLocalServerReadyFuncValue = authentication.DefaultLocalServerReadyFunc
+	_wireNewFuncValue         = oidcclient.NewFunc(oidcclient.New)
+	_wireCertpoolNewFuncValue = certpool.NewFunc(certpool.New)
 )
-
-func NewCmdForHeadless(loggerInterface logger.Interface, localServerReadyFunc authentication.LocalServerReadyFunc, credentialpluginInterface credentialplugin.Interface) cmd.Interface {
-	factory := &oidcclient.Factory{
-		Logger: loggerInterface,
-	}
-	decoder := &jwtdecoder.Decoder{}
-	envEnv := &env.Env{}
-	authCode := &authentication.AuthCode{
-		Env:                  envEnv,
-		Logger:               loggerInterface,
-		LocalServerReadyFunc: localServerReadyFunc,
-	}
-	authCodeKeyboard := &authentication.AuthCodeKeyboard{
-		Env:    envEnv,
-		Logger: loggerInterface,
-	}
-	ropc := &authentication.ROPC{
-		Env:    envEnv,
-		Logger: loggerInterface,
-	}
-	authenticationAuthentication := &authentication.Authentication{
-		OIDCClientFactory: factory,
-		JWTDecoder:        decoder,
-		Logger:            loggerInterface,
-		Env:               envEnv,
-		AuthCode:          authCode,
-		AuthCodeKeyboard:  authCodeKeyboard,
-		ROPC:              ropc,
-	}
-	kubeconfigKubeconfig := &kubeconfig.Kubeconfig{
-		Logger: loggerInterface,
-	}
-	certpoolFactory := &certpool.Factory{}
-	standaloneStandalone := &standalone.Standalone{
-		Authentication:  authenticationAuthentication,
-		Kubeconfig:      kubeconfigKubeconfig,
-		CertPoolFactory: certpoolFactory,
-		Logger:          loggerInterface,
-	}
-	root := &cmd.Root{
-		Standalone: standaloneStandalone,
-		Logger:     loggerInterface,
-	}
-	repository := &tokencache.Repository{}
-	getToken := &credentialplugin2.GetToken{
-		Authentication:       authenticationAuthentication,
-		TokenCacheRepository: repository,
-		CertPoolFactory:      certpoolFactory,
-		Interaction:          credentialpluginInterface,
-		Logger:               loggerInterface,
-	}
-	cmdGetToken := &cmd.GetToken{
-		GetToken: getToken,
-		Logger:   loggerInterface,
-	}
-	setupSetup := &setup.Setup{
-		Authentication:  authenticationAuthentication,
-		CertPoolFactory: certpoolFactory,
-		Logger:          loggerInterface,
-	}
-	cmdSetup := &cmd.Setup{
-		Setup: setupSetup,
-	}
-	cmdCmd := &cmd.Cmd{
-		Root:     root,
-		GetToken: cmdGetToken,
-		Setup:    cmdSetup,
-		Logger:   loggerInterface,
-	}
-	return cmdCmd
-}

pkg/usecases/authentication/authentication.go

@@ -90,13 +90,13 @@ const passwordPrompt = "Password: "
 // If the Password is not set, it asks a password by the prompt.
 //
 type Authentication struct {
-	OIDCClientFactory oidcclient.FactoryInterface
-	JWTDecoder        jwtdecoder.Interface
-	Logger            logger.Interface
-	Env               env.Interface
-	AuthCode          *AuthCode
-	AuthCodeKeyboard  *AuthCodeKeyboard
-	ROPC              *ROPC
+	NewOIDCClient    oidcclient.NewFunc
+	JWTDecoder       jwtdecoder.Interface
+	Logger           logger.Interface
+	Env              env.Interface
+	AuthCode         *AuthCode
+	AuthCodeKeyboard *AuthCodeKeyboard
+	ROPC             *ROPC
 }
 
 func (u *Authentication) Do(ctx context.Context, in Input) (*Output, error) {
@@ -122,13 +122,14 @@ func (u *Authentication) Do(ctx context.Context, in Input) (*Output, error) {
 	}
 
 	u.Logger.V(1).Infof("initializing an OpenID Connect client")
-	client, err := u.OIDCClientFactory.New(ctx, oidcclient.Config{
+	client, err := u.NewOIDCClient(ctx, oidcclient.Config{
 		IssuerURL:     in.IssuerURL,
 		ClientID:      in.ClientID,
 		ClientSecret:  in.ClientSecret,
 		ExtraScopes:   in.ExtraScopes,
 		CertPool:      in.CertPool,
 		SkipTLSVerify: in.SkipTLSVerify,
+		Logger:        u.Logger,
 	})
 	if err != nil {
 		return nil, xerrors.Errorf("could not initialize the OpenID Connect client: %w", err)

pkg/usecases/authentication/authentication_test.go

@@ -7,8 +7,10 @@ import (
 
 	"github.com/golang/mock/gomock"
 	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
 	"github.com/int128/kubelogin/pkg/adaptors/env/mock_env"
 	"github.com/int128/kubelogin/pkg/adaptors/jwtdecoder/mock_jwtdecoder"
+	"github.com/int128/kubelogin/pkg/adaptors/logger"
 	"github.com/int128/kubelogin/pkg/adaptors/logger/mock_logger"
 	"github.com/int128/kubelogin/pkg/adaptors/oidcclient"
 	"github.com/int128/kubelogin/pkg/adaptors/oidcclient/mock_oidcclient"
@@ -16,6 +18,8 @@ import (
 	"golang.org/x/xerrors"
 )
 
+var cmpIgnoreLogger = cmpopts.IgnoreInterfaces(struct{ logger.Interface }{})
+
 func TestAuthentication_Do(t *testing.T) {
 	dummyTokenClaims := oidc.Claims{
 		Subject: "YOUR_SUBJECT",
@@ -25,6 +29,7 @@ func TestAuthentication_Do(t *testing.T) {
 	timeBeforeExpiry := time.Date(2019, 1, 2, 1, 0, 0, 0, time.UTC)
 	timeAfterExpiry := time.Date(2019, 1, 2, 4, 0, 0, 0, time.UTC)
 	timeout := 5 * time.Second
+	testingLogger := mock_logger.New(t)
 
 	t.Run("HasValidIDToken", func(t *testing.T) {
 		ctrl := gomock.NewController(t)
@@ -46,10 +51,9 @@ func TestAuthentication_Do(t *testing.T) {
 			Decode("VALID_ID_TOKEN").
 			Return(&dummyTokenClaims, nil)
 		u := Authentication{
-			OIDCClientFactory: mock_oidcclient.NewMockFactoryInterface(ctrl),
-			JWTDecoder:        mockDecoder,
-			Logger:            mock_logger.New(t),
-			Env:               mockEnv,
+			JWTDecoder: mockDecoder,
+			Logger:     testingLogger,
+			Env:        mockEnv,
 		}
 		got, err := u.Do(ctx, in)
 		if err != nil {
@@ -93,19 +97,21 @@ func TestAuthentication_Do(t *testing.T) {
 				RefreshToken:  "NEW_REFRESH_TOKEN",
 				IDTokenClaims: dummyTokenClaims,
 			}, nil)
-		mockOIDCClientFactory := mock_oidcclient.NewMockFactoryInterface(ctrl)
-		mockOIDCClientFactory.EXPECT().
-			New(ctx, oidcclient.Config{
-				IssuerURL:    "https://issuer.example.com",
-				ClientID:     "YOUR_CLIENT_ID",
-				ClientSecret: "YOUR_CLIENT_SECRET",
-			}).
-			Return(mockOIDCClient, nil)
 		u := Authentication{
-			OIDCClientFactory: mockOIDCClientFactory,
-			JWTDecoder:        mockDecoder,
-			Logger:            mock_logger.New(t),
-			Env:               mockEnv,
+			NewOIDCClient: func(_ context.Context, got oidcclient.Config) (oidcclient.Interface, error) {
+				want := oidcclient.Config{
+					IssuerURL:    "https://issuer.example.com",
+					ClientID:     "YOUR_CLIENT_ID",
+					ClientSecret: "YOUR_CLIENT_SECRET",
+				}
+				if diff := cmp.Diff(want, got, cmpIgnoreLogger); diff != "" {
+					t.Errorf("mismatch (-want +got):\n%s", diff)
+				}
+				return mockOIDCClient, nil
+			},
+			JWTDecoder: mockDecoder,
+			Logger:     testingLogger,
+			Env:        mockEnv,
 		}
 		got, err := u.Do(ctx, in)
 		if err != nil {
@@ -161,21 +167,23 @@ func TestAuthentication_Do(t *testing.T) {
 				RefreshToken:  "NEW_REFRESH_TOKEN",
 				IDTokenClaims: dummyTokenClaims,
 			}, nil)
-		mockOIDCClientFactory := mock_oidcclient.NewMockFactoryInterface(ctrl)
-		mockOIDCClientFactory.EXPECT().
-			New(ctx, oidcclient.Config{
-				IssuerURL:    "https://issuer.example.com",
-				ClientID:     "YOUR_CLIENT_ID",
-				ClientSecret: "YOUR_CLIENT_SECRET",
-			}).
-			Return(mockOIDCClient, nil)
 		u := Authentication{
-			OIDCClientFactory: mockOIDCClientFactory,
-			JWTDecoder:        mockDecoder,
-			Logger:            mock_logger.New(t),
-			Env:               mockEnv,
+			NewOIDCClient: func(_ context.Context, got oidcclient.Config) (oidcclient.Interface, error) {
+				want := oidcclient.Config{
+					IssuerURL:    "https://issuer.example.com",
+					ClientID:     "YOUR_CLIENT_ID",
+					ClientSecret: "YOUR_CLIENT_SECRET",
+				}
+				if diff := cmp.Diff(want, got, cmpIgnoreLogger); diff != "" {
+					t.Errorf("mismatch (-want +got):\n%s", diff)
+				}
+				return mockOIDCClient, nil
+			},
+			JWTDecoder: mockDecoder,
+			Logger:     testingLogger,
+			Env:        mockEnv,
 			AuthCode: &AuthCode{
-				Logger: mock_logger.New(t),
+				Logger: testingLogger,
 			},
 		}
 		got, err := u.Do(ctx, in)
@@ -216,19 +224,21 @@ func TestAuthentication_Do(t *testing.T) {
 				RefreshToken:  "YOUR_REFRESH_TOKEN",
 				IDTokenClaims: dummyTokenClaims,
 			}, nil)
-		mockOIDCClientFactory := mock_oidcclient.NewMockFactoryInterface(ctrl)
-		mockOIDCClientFactory.EXPECT().
-			New(ctx, oidcclient.Config{
-				IssuerURL:    "https://issuer.example.com",
-				ClientID:     "YOUR_CLIENT_ID",
-				ClientSecret: "YOUR_CLIENT_SECRET",
-			}).
-			Return(mockOIDCClient, nil)
 		u := Authentication{
-			OIDCClientFactory: mockOIDCClientFactory,
-			Logger:            mock_logger.New(t),
+			NewOIDCClient: func(_ context.Context, got oidcclient.Config) (oidcclient.Interface, error) {
+				want := oidcclient.Config{
+					IssuerURL:    "https://issuer.example.com",
+					ClientID:     "YOUR_CLIENT_ID",
+					ClientSecret: "YOUR_CLIENT_SECRET",
+				}
+				if diff := cmp.Diff(want, got, cmpIgnoreLogger); diff != "" {
+					t.Errorf("mismatch (-want +got):\n%s", diff)
+				}
+				return mockOIDCClient, nil
+			},
+			Logger: testingLogger,
 			ROPC: &ROPC{
-				Logger: mock_logger.New(t),
+				Logger: testingLogger,
 			},
 		}
 		got, err := u.Do(ctx, in)

pkg/usecases/credentialplugin/get_token.go

@@ -41,7 +41,7 @@ type Input struct {
 type GetToken struct {
 	Authentication       authentication.Interface
 	TokenCacheRepository tokencache.Interface
-	CertPoolFactory      certpool.FactoryInterface
+	NewCertPool          certpool.NewFunc
 	Interaction          credentialplugin.Interface
 	Logger               logger.Interface
 }
@@ -74,7 +74,7 @@ func (u *GetToken) getTokenFromCacheOrProvider(ctx context.Context, in Input) (*
 		u.Logger.V(1).Infof("could not find a token cache: %s", err)
 		tokenCacheValue = &tokencache.Value{}
 	}
-	certPool := u.CertPoolFactory.New()
+	certPool := u.NewCertPool()
 	if in.CACertFilename != "" {
 		if err := certPool.AddFile(in.CACertFilename); err != nil {
 			return nil, xerrors.Errorf("could not load the certificate: %w", err)

pkg/usecases/credentialplugin/get_token_test.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/golang/mock/gomock"
+	"github.com/int128/kubelogin/pkg/adaptors/certpool"
 	"github.com/int128/kubelogin/pkg/adaptors/certpool/mock_certpool"
 	"github.com/int128/kubelogin/pkg/adaptors/credentialplugin"
 	"github.com/int128/kubelogin/pkg/adaptors/credentialplugin/mock_credentialplugin"
@@ -42,10 +43,6 @@ func TestGetToken_Do(t *testing.T) {
 		mockCertPool := mock_certpool.NewMockInterface(ctrl)
 		mockCertPool.EXPECT().
 			AddFile("/path/to/cert")
-		mockCertPoolFactory := mock_certpool.NewMockFactoryInterface(ctrl)
-		mockCertPoolFactory.EXPECT().
-			New().
-			Return(mockCertPool)
 		mockAuthentication := mock_authentication.NewMockInterface(ctrl)
 		mockAuthentication.EXPECT().
 			Do(ctx, authentication.Input{
@@ -94,7 +91,7 @@ func TestGetToken_Do(t *testing.T) {
 		u := GetToken{
 			Authentication:       mockAuthentication,
 			TokenCacheRepository: tokenCacheRepository,
-			CertPoolFactory:      mockCertPoolFactory,
+			NewCertPool:          func() certpool.Interface { return mockCertPool },
 			Interaction:          credentialPluginInteraction,
 			Logger:               mock_logger.New(t),
 		}
@@ -114,10 +111,6 @@ func TestGetToken_Do(t *testing.T) {
 			TokenCacheDir: "/path/to/token-cache",
 		}
 		mockCertPool := mock_certpool.NewMockInterface(ctrl)
-		mockCertPoolFactory := mock_certpool.NewMockFactoryInterface(ctrl)
-		mockCertPoolFactory.EXPECT().
-			New().
-			Return(mockCertPool)
 		mockAuthentication := mock_authentication.NewMockInterface(ctrl)
 		mockAuthentication.EXPECT().
 			Do(ctx, authentication.Input{
@@ -151,7 +144,7 @@ func TestGetToken_Do(t *testing.T) {
 		u := GetToken{
 			Authentication:       mockAuthentication,
 			TokenCacheRepository: tokenCacheRepository,
-			CertPoolFactory:      mockCertPoolFactory,
+			NewCertPool:          func() certpool.Interface { return mockCertPool },
 			Interaction:          credentialPluginInteraction,
 			Logger:               mock_logger.New(t),
 		}
@@ -171,10 +164,6 @@ func TestGetToken_Do(t *testing.T) {
 			TokenCacheDir: "/path/to/token-cache",
 		}
 		mockCertPool := mock_certpool.NewMockInterface(ctrl)
-		mockCertPoolFactory := mock_certpool.NewMockFactoryInterface(ctrl)
-		mockCertPoolFactory.EXPECT().
-			New().
-			Return(mockCertPool)
 		mockAuthentication := mock_authentication.NewMockInterface(ctrl)
 		mockAuthentication.EXPECT().
 			Do(ctx, authentication.Input{
@@ -195,7 +184,7 @@ func TestGetToken_Do(t *testing.T) {
 		u := GetToken{
 			Authentication:       mockAuthentication,
 			TokenCacheRepository: tokenCacheRepository,
-			CertPoolFactory:      mockCertPoolFactory,
+			NewCertPool:          func() certpool.Interface { return mockCertPool },
 			Interaction:          mock_credentialplugin.NewMockInterface(ctrl),
 			Logger:               mock_logger.New(t),
 		}

pkg/usecases/setup/setup.go

@@ -21,7 +21,7 @@ type Interface interface {
 }
 
 type Setup struct {
-	Authentication  authentication.Interface
-	CertPoolFactory certpool.FactoryInterface
-	Logger          logger.Interface
+	Authentication authentication.Interface
+	NewCertPool    certpool.NewFunc
+	Logger         logger.Interface
 }

pkg/usecases/setup/stage2.go

@@ -76,7 +76,7 @@ type Stage2Input struct {
 
 func (u *Setup) DoStage2(ctx context.Context, in Stage2Input) error {
 	u.Logger.Printf(`## 2. Verify authentication`)
-	certPool := u.CertPoolFactory.New()
+	certPool := u.NewCertPool()
 	if in.CACertFilename != "" {
 		if err := certPool.AddFile(in.CACertFilename); err != nil {
 			return xerrors.Errorf("could not load the certificate: %w", err)

pkg/usecases/setup/stage2_test.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/golang/mock/gomock"
+	"github.com/int128/kubelogin/pkg/adaptors/certpool"
 	"github.com/int128/kubelogin/pkg/adaptors/certpool/mock_certpool"
 	"github.com/int128/kubelogin/pkg/adaptors/logger/mock_logger"
 	"github.com/int128/kubelogin/pkg/domain/oidc"
@@ -37,10 +38,6 @@ func TestSetup_DoStage2(t *testing.T) {
 	mockCertPool := mock_certpool.NewMockInterface(ctrl)
 	mockCertPool.EXPECT().
 		AddFile("/path/to/cert")
-	mockCertPoolFactory := mock_certpool.NewMockFactoryInterface(ctrl)
-	mockCertPoolFactory.EXPECT().
-		New().
-		Return(mockCertPool)
 	mockAuthentication := mock_authentication.NewMockInterface(ctrl)
 	mockAuthentication.EXPECT().
 		Do(ctx, authentication.Input{
@@ -58,9 +55,9 @@ func TestSetup_DoStage2(t *testing.T) {
 			IDTokenClaims: dummyTokenClaims,
 		}, nil)
 	u := Setup{
-		Authentication:  mockAuthentication,
-		CertPoolFactory: mockCertPoolFactory,
-		Logger:          mock_logger.New(t),
+		Authentication: mockAuthentication,
+		NewCertPool:    func() certpool.Interface { return mockCertPool },
+		Logger:         mock_logger.New(t),
 	}
 	if err := u.DoStage2(ctx, in); err != nil {
 		t.Errorf("DoStage2 returned error: %+v", err)

pkg/usecases/standalone/standalone.go

@@ -46,10 +46,10 @@ See https://github.com/int128/kubelogin for more.
 // Otherwise, update the kubeconfig.
 //
 type Standalone struct {
-	Authentication  authentication.Interface
-	Kubeconfig      kubeconfig.Interface
-	CertPoolFactory certpool.FactoryInterface
-	Logger          logger.Interface
+	Authentication authentication.Interface
+	Kubeconfig     kubeconfig.Interface
+	NewCertPool    certpool.NewFunc
+	Logger         logger.Interface
 }
 
 func (u *Standalone) Do(ctx context.Context, in Input) error {
@@ -65,7 +65,7 @@ func (u *Standalone) Do(ctx context.Context, in Input) error {
 	}
 	u.Logger.V(1).Infof("using the authentication provider of the user %s", authProvider.UserName)
 	u.Logger.V(1).Infof("a token will be written to %s", authProvider.LocationOfOrigin)
-	certPool := u.CertPoolFactory.New()
+	certPool := u.NewCertPool()
 	if authProvider.IDPCertificateAuthority != "" {
 		if err := certPool.AddFile(authProvider.IDPCertificateAuthority); err != nil {
 			return xerrors.Errorf("could not load the certificate of idp-certificate-authority: %w", err)

pkg/usecases/standalone/standalone_test.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/golang/mock/gomock"
+	"github.com/int128/kubelogin/pkg/adaptors/certpool"
 	"github.com/int128/kubelogin/pkg/adaptors/certpool/mock_certpool"
 	"github.com/int128/kubelogin/pkg/adaptors/kubeconfig"
 	"github.com/int128/kubelogin/pkg/adaptors/kubeconfig/mock_kubeconfig"
@@ -52,10 +53,6 @@ func TestStandalone_Do(t *testing.T) {
 			AddFile("/path/to/cert2")
 		mockCertPool.EXPECT().
 			AddBase64Encoded("BASE64ENCODED")
-		mockCertPoolFactory := mock_certpool.NewMockFactoryInterface(ctrl)
-		mockCertPoolFactory.EXPECT().
-			New().
-			Return(mockCertPool)
 		mockKubeconfig := mock_kubeconfig.NewMockInterface(ctrl)
 		mockKubeconfig.EXPECT().
 			GetCurrentAuthProvider("/path/to/kubeconfig", kubeconfig.ContextName("theContext"), kubeconfig.UserName("theUser")).
@@ -88,10 +85,10 @@ func TestStandalone_Do(t *testing.T) {
 				IDTokenClaims: dummyTokenClaims,
 			}, nil)
 		u := Standalone{
-			Authentication:  mockAuthentication,
-			Kubeconfig:      mockKubeconfig,
-			CertPoolFactory: mockCertPoolFactory,
-			Logger:          mock_logger.New(t),
+			Authentication: mockAuthentication,
+			Kubeconfig:     mockKubeconfig,
+			NewCertPool:    func() certpool.Interface { return mockCertPool },
+			Logger:         mock_logger.New(t),
 		}
 		if err := u.Do(ctx, in); err != nil {
 			t.Errorf("Do returned error: %+v", err)
@@ -112,10 +109,6 @@ func TestStandalone_Do(t *testing.T) {
 			IDToken:          "VALID_ID_TOKEN",
 		}
 		mockCertPool := mock_certpool.NewMockInterface(ctrl)
-		mockCertPoolFactory := mock_certpool.NewMockFactoryInterface(ctrl)
-		mockCertPoolFactory.EXPECT().
-			New().
-			Return(mockCertPool)
 		mockKubeconfig := mock_kubeconfig.NewMockInterface(ctrl)
 		mockKubeconfig.EXPECT().
 			GetCurrentAuthProvider("", kubeconfig.ContextName(""), kubeconfig.UserName("")).
@@ -135,10 +128,10 @@ func TestStandalone_Do(t *testing.T) {
 				IDTokenClaims:          dummyTokenClaims,
 			}, nil)
 		u := Standalone{
-			Authentication:  mockAuthentication,
-			Kubeconfig:      mockKubeconfig,
-			CertPoolFactory: mockCertPoolFactory,
-			Logger:          mock_logger.New(t),
+			Authentication: mockAuthentication,
+			Kubeconfig:     mockKubeconfig,
+			NewCertPool:    func() certpool.Interface { return mockCertPool },
+			Logger:         mock_logger.New(t),
 		}
 		if err := u.Do(ctx, in); err != nil {
 			t.Errorf("Do returned error: %+v", err)
@@ -150,17 +143,15 @@ func TestStandalone_Do(t *testing.T) {
 		defer ctrl.Finish()
 		ctx := context.TODO()
 		in := Input{}
-		mockCertPoolFactory := mock_certpool.NewMockFactoryInterface(ctrl)
 		mockKubeconfig := mock_kubeconfig.NewMockInterface(ctrl)
 		mockKubeconfig.EXPECT().
 			GetCurrentAuthProvider("", kubeconfig.ContextName(""), kubeconfig.UserName("")).
 			Return(nil, xerrors.New("no oidc config"))
 		mockAuthentication := mock_authentication.NewMockInterface(ctrl)
 		u := Standalone{
-			Authentication:  mockAuthentication,
-			Kubeconfig:      mockKubeconfig,
-			CertPoolFactory: mockCertPoolFactory,
-			Logger:          mock_logger.New(t),
+			Authentication: mockAuthentication,
+			Kubeconfig:     mockKubeconfig,
+			Logger:         mock_logger.New(t),
 		}
 		if err := u.Do(ctx, in); err == nil {
 			t.Errorf("err wants non-nil but nil")
@@ -180,10 +171,6 @@ func TestStandalone_Do(t *testing.T) {
 			ClientSecret:     "YOUR_CLIENT_SECRET",
 		}
 		mockCertPool := mock_certpool.NewMockInterface(ctrl)
-		mockCertPoolFactory := mock_certpool.NewMockFactoryInterface(ctrl)
-		mockCertPoolFactory.EXPECT().
-			New().
-			Return(mockCertPool)
 		mockKubeconfig := mock_kubeconfig.NewMockInterface(ctrl)
 		mockKubeconfig.EXPECT().
 			GetCurrentAuthProvider("", kubeconfig.ContextName(""), kubeconfig.UserName("")).
@@ -198,10 +185,10 @@ func TestStandalone_Do(t *testing.T) {
 			}).
 			Return(nil, xerrors.New("authentication error"))
 		u := Standalone{
-			Authentication:  mockAuthentication,
-			Kubeconfig:      mockKubeconfig,
-			CertPoolFactory: mockCertPoolFactory,
-			Logger:          mock_logger.New(t),
+			Authentication: mockAuthentication,
+			Kubeconfig:     mockKubeconfig,
+			NewCertPool:    func() certpool.Interface { return mockCertPool },
+			Logger:         mock_logger.New(t),
 		}
 		if err := u.Do(ctx, in); err == nil {
 			t.Errorf("err wants non-nil but nil")
@@ -221,10 +208,6 @@ func TestStandalone_Do(t *testing.T) {
 			ClientSecret:     "YOUR_CLIENT_SECRET",
 		}
 		mockCertPool := mock_certpool.NewMockInterface(ctrl)
-		mockCertPoolFactory := mock_certpool.NewMockFactoryInterface(ctrl)
-		mockCertPoolFactory.EXPECT().
-			New().
-			Return(mockCertPool)
 		mockKubeconfig := mock_kubeconfig.NewMockInterface(ctrl)
 		mockKubeconfig.EXPECT().
 			GetCurrentAuthProvider("", kubeconfig.ContextName(""), kubeconfig.UserName("")).
@@ -254,10 +237,10 @@ func TestStandalone_Do(t *testing.T) {
 				IDTokenClaims: dummyTokenClaims,
 			}, nil)
 		u := Standalone{
-			Authentication:  mockAuthentication,
-			Kubeconfig:      mockKubeconfig,
-			CertPoolFactory: mockCertPoolFactory,
-			Logger:          mock_logger.New(t),
+			Authentication: mockAuthentication,
+			Kubeconfig:     mockKubeconfig,
+			NewCertPool:    func() certpool.Interface { return mockCertPool },
+			Logger:         mock_logger.New(t),
 		}
 		if err := u.Do(ctx, in); err == nil {
 			t.Errorf("err wants non-nil but nil")