diff --git a/weed/iam/sts/session_store.go b/weed/iam/sts/session_store.go
new file mode 100644
index 000000000..f646caf02
--- /dev/null
+++ b/weed/iam/sts/session_store.go
@@ -0,0 +1,144 @@
+package sts
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"time"
+)
+
+// MemorySessionStore implements SessionStore using in-memory storage
+type MemorySessionStore struct {
+	sessions map[string]*SessionInfo
+	mutex    sync.RWMutex
+}
+
+// NewMemorySessionStore creates a new memory-based session store
+func NewMemorySessionStore() *MemorySessionStore {
+	return &MemorySessionStore{
+		sessions: make(map[string]*SessionInfo),
+	}
+}
+
+// StoreSession stores session information in memory
+func (m *MemorySessionStore) StoreSession(ctx context.Context, sessionId string, session *SessionInfo) error {
+	if sessionId == "" {
+		return fmt.Errorf("session ID cannot be empty")
+	}
+	
+	if session == nil {
+		return fmt.Errorf("session cannot be nil")
+	}
+	
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+	
+	m.sessions[sessionId] = session
+	return nil
+}
+
+// GetSession retrieves session information from memory
+func (m *MemorySessionStore) GetSession(ctx context.Context, sessionId string) (*SessionInfo, error) {
+	if sessionId == "" {
+		return nil, fmt.Errorf("session ID cannot be empty")
+	}
+	
+	m.mutex.RLock()
+	defer m.mutex.RUnlock()
+	
+	session, exists := m.sessions[sessionId]
+	if !exists {
+		return nil, fmt.Errorf("session not found")
+	}
+	
+	// Check if session has expired
+	if time.Now().After(session.ExpiresAt) {
+		return nil, fmt.Errorf("session has expired")
+	}
+	
+	return session, nil
+}
+
+// RevokeSession revokes a session from memory
+func (m *MemorySessionStore) RevokeSession(ctx context.Context, sessionId string) error {
+	if sessionId == "" {
+		return fmt.Errorf("session ID cannot be empty")
+	}
+	
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+	
+	delete(m.sessions, sessionId)
+	return nil
+}
+
+// CleanupExpiredSessions removes expired sessions from memory
+func (m *MemorySessionStore) CleanupExpiredSessions(ctx context.Context) error {
+	m.mutex.Lock()
+	defer m.mutex.Unlock()
+	
+	now := time.Now()
+	for sessionId, session := range m.sessions {
+		if now.After(session.ExpiresAt) {
+			delete(m.sessions, sessionId)
+		}
+	}
+	
+	return nil
+}
+
+// FilerSessionStore implements SessionStore using SeaweedFS filer
+type FilerSessionStore struct {
+	// TODO: Add filer client configuration
+	basePath string
+}
+
+// NewFilerSessionStore creates a new filer-based session store
+func NewFilerSessionStore(config map[string]interface{}) (*FilerSessionStore, error) {
+	// TODO: Implement filer session store initialization
+	// 1. Parse configuration for filer connection
+	// 2. Set up filer client
+	// 3. Configure base path for session storage
+	
+	return nil, fmt.Errorf("filer session store not implemented yet")
+}
+
+// StoreSession stores session information in filer
+func (f *FilerSessionStore) StoreSession(ctx context.Context, sessionId string, session *SessionInfo) error {
+	// TODO: Implement filer session storage
+	// 1. Serialize session information to JSON/protobuf
+	// 2. Store in filer at configured path + sessionId
+	// 3. Handle errors and retries
+	
+	return fmt.Errorf("filer session storage not implemented yet")
+}
+
+// GetSession retrieves session information from filer
+func (f *FilerSessionStore) GetSession(ctx context.Context, sessionId string) (*SessionInfo, error) {
+	// TODO: Implement filer session retrieval
+	// 1. Read session data from filer
+	// 2. Deserialize JSON/protobuf to SessionInfo
+	// 3. Check expiration
+	// 4. Handle not found cases
+	
+	return nil, fmt.Errorf("filer session retrieval not implemented yet")
+}
+
+// RevokeSession revokes a session from filer
+func (f *FilerSessionStore) RevokeSession(ctx context.Context, sessionId string) error {
+	// TODO: Implement filer session revocation
+	// 1. Delete session file from filer
+	// 2. Handle errors
+	
+	return fmt.Errorf("filer session revocation not implemented yet")
+}
+
+// CleanupExpiredSessions removes expired sessions from filer
+func (f *FilerSessionStore) CleanupExpiredSessions(ctx context.Context) error {
+	// TODO: Implement filer session cleanup
+	// 1. List all session files in base path
+	// 2. Read and check expiration times
+	// 3. Delete expired sessions
+	
+	return fmt.Errorf("filer session cleanup not implemented yet")
+}
diff --git a/weed/iam/sts/sts_service.go b/weed/iam/sts/sts_service.go
new file mode 100644
index 000000000..25aae268d
--- /dev/null
+++ b/weed/iam/sts/sts_service.go
@@ -0,0 +1,317 @@
+package sts
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/seaweedfs/seaweedfs/weed/iam/providers"
+)
+
+// STSService provides Security Token Service functionality
+type STSService struct {
+	config       *STSConfig
+	initialized  bool
+	providers    map[string]providers.IdentityProvider
+	sessionStore SessionStore
+}
+
+// STSConfig holds STS service configuration
+type STSConfig struct {
+	// TokenDuration is the default duration for issued tokens
+	TokenDuration time.Duration `json:"tokenDuration"`
+	
+	// MaxSessionLength is the maximum duration for any session
+	MaxSessionLength time.Duration `json:"maxSessionLength"`
+	
+	// Issuer is the STS issuer identifier
+	Issuer string `json:"issuer"`
+	
+	// SigningKey is used to sign session tokens
+	SigningKey []byte `json:"signingKey"`
+	
+	// SessionStore configuration
+	SessionStoreType string                 `json:"sessionStoreType"` // memory, filer, redis
+	SessionStoreConfig map[string]interface{} `json:"sessionStoreConfig,omitempty"`
+}
+
+// AssumeRoleWithWebIdentityRequest represents a request to assume role with web identity
+type AssumeRoleWithWebIdentityRequest struct {
+	// RoleArn is the ARN of the role to assume
+	RoleArn string `json:"RoleArn"`
+	
+	// WebIdentityToken is the OIDC token from the identity provider
+	WebIdentityToken string `json:"WebIdentityToken"`
+	
+	// RoleSessionName is a name for the assumed role session
+	RoleSessionName string `json:"RoleSessionName"`
+	
+	// DurationSeconds is the duration of the role session (optional)
+	DurationSeconds *int64 `json:"DurationSeconds,omitempty"`
+	
+	// Policy is an optional session policy (optional)
+	Policy *string `json:"Policy,omitempty"`
+}
+
+// AssumeRoleWithCredentialsRequest represents a request to assume role with username/password
+type AssumeRoleWithCredentialsRequest struct {
+	// RoleArn is the ARN of the role to assume
+	RoleArn string `json:"RoleArn"`
+	
+	// Username is the username for authentication
+	Username string `json:"Username"`
+	
+	// Password is the password for authentication
+	Password string `json:"Password"`
+	
+	// RoleSessionName is a name for the assumed role session
+	RoleSessionName string `json:"RoleSessionName"`
+	
+	// ProviderName is the name of the identity provider to use
+	ProviderName string `json:"ProviderName"`
+	
+	// DurationSeconds is the duration of the role session (optional)
+	DurationSeconds *int64 `json:"DurationSeconds,omitempty"`
+}
+
+// AssumeRoleResponse represents the response from assume role operations
+type AssumeRoleResponse struct {
+	// Credentials contains the temporary security credentials
+	Credentials *Credentials `json:"Credentials"`
+	
+	// AssumedRoleUser contains information about the assumed role user
+	AssumedRoleUser *AssumedRoleUser `json:"AssumedRoleUser"`
+	
+	// PackedPolicySize is the percentage of max policy size used (AWS compatibility)
+	PackedPolicySize *int64 `json:"PackedPolicySize,omitempty"`
+}
+
+// Credentials represents temporary security credentials
+type Credentials struct {
+	// AccessKeyId is the access key ID
+	AccessKeyId string `json:"AccessKeyId"`
+	
+	// SecretAccessKey is the secret access key
+	SecretAccessKey string `json:"SecretAccessKey"`
+	
+	// SessionToken is the session token
+	SessionToken string `json:"SessionToken"`
+	
+	// Expiration is when the credentials expire
+	Expiration time.Time `json:"Expiration"`
+}
+
+// AssumedRoleUser contains information about the assumed role user
+type AssumedRoleUser struct {
+	// AssumedRoleId is the unique identifier of the assumed role
+	AssumedRoleId string `json:"AssumedRoleId"`
+	
+	// Arn is the ARN of the assumed role user
+	Arn string `json:"Arn"`
+	
+	// Subject is the subject identifier from the identity provider
+	Subject string `json:"Subject,omitempty"`
+}
+
+// SessionInfo represents information about an active session
+type SessionInfo struct {
+	// SessionId is the unique identifier for the session
+	SessionId string `json:"sessionId"`
+	
+	// SessionName is the name of the role session
+	SessionName string `json:"sessionName"`
+	
+	// RoleArn is the ARN of the assumed role
+	RoleArn string `json:"roleArn"`
+	
+	// Subject is the subject identifier from the identity provider
+	Subject string `json:"subject"`
+	
+	// Provider is the identity provider used
+	Provider string `json:"provider"`
+	
+	// CreatedAt is when the session was created
+	CreatedAt time.Time `json:"createdAt"`
+	
+	// ExpiresAt is when the session expires
+	ExpiresAt time.Time `json:"expiresAt"`
+	
+	// Credentials are the temporary credentials for this session
+	Credentials *Credentials `json:"credentials"`
+}
+
+// SessionStore defines the interface for storing session information
+type SessionStore interface {
+	// StoreSession stores session information
+	StoreSession(ctx context.Context, sessionId string, session *SessionInfo) error
+	
+	// GetSession retrieves session information
+	GetSession(ctx context.Context, sessionId string) (*SessionInfo, error)
+	
+	// RevokeSession revokes a session
+	RevokeSession(ctx context.Context, sessionId string) error
+	
+	// CleanupExpiredSessions removes expired sessions
+	CleanupExpiredSessions(ctx context.Context) error
+}
+
+// NewSTSService creates a new STS service
+func NewSTSService() *STSService {
+	return &STSService{
+		providers: make(map[string]providers.IdentityProvider),
+	}
+}
+
+// Initialize initializes the STS service with configuration
+func (s *STSService) Initialize(config *STSConfig) error {
+	if config == nil {
+		return fmt.Errorf("config cannot be nil")
+	}
+	
+	if err := s.validateConfig(config); err != nil {
+		return fmt.Errorf("invalid STS configuration: %w", err)
+	}
+	
+	s.config = config
+	
+	// Initialize session store
+	sessionStore, err := s.createSessionStore(config)
+	if err != nil {
+		return fmt.Errorf("failed to initialize session store: %w", err)
+	}
+	s.sessionStore = sessionStore
+	
+	s.initialized = true
+	return nil
+}
+
+// validateConfig validates the STS configuration
+func (s *STSService) validateConfig(config *STSConfig) error {
+	if config.TokenDuration <= 0 {
+		return fmt.Errorf("token duration must be positive")
+	}
+	
+	if config.MaxSessionLength <= 0 {
+		return fmt.Errorf("max session length must be positive")
+	}
+	
+	if config.Issuer == "" {
+		return fmt.Errorf("issuer is required")
+	}
+	
+	if len(config.SigningKey) < 16 {
+		return fmt.Errorf("signing key must be at least 16 bytes")
+	}
+	
+	return nil
+}
+
+// createSessionStore creates a session store based on configuration
+func (s *STSService) createSessionStore(config *STSConfig) (SessionStore, error) {
+	switch config.SessionStoreType {
+	case "", "memory":
+		return NewMemorySessionStore(), nil
+	case "filer":
+		return NewFilerSessionStore(config.SessionStoreConfig)
+	default:
+		return nil, fmt.Errorf("unsupported session store type: %s", config.SessionStoreType)
+	}
+}
+
+// IsInitialized returns whether the service is initialized
+func (s *STSService) IsInitialized() bool {
+	return s.initialized
+}
+
+// RegisterProvider registers an identity provider
+func (s *STSService) RegisterProvider(provider providers.IdentityProvider) error {
+	if provider == nil {
+		return fmt.Errorf("provider cannot be nil")
+	}
+	
+	name := provider.Name()
+	if name == "" {
+		return fmt.Errorf("provider name cannot be empty")
+	}
+	
+	s.providers[name] = provider
+	return nil
+}
+
+// AssumeRoleWithWebIdentity assumes a role using a web identity token (OIDC)
+func (s *STSService) AssumeRoleWithWebIdentity(ctx context.Context, request *AssumeRoleWithWebIdentityRequest) (*AssumeRoleResponse, error) {
+	if !s.initialized {
+		return nil, fmt.Errorf("STS service not initialized")
+	}
+	
+	if request == nil {
+		return nil, fmt.Errorf("request cannot be nil")
+	}
+	
+	// TODO: Implement AssumeRoleWithWebIdentity
+	// 1. Validate the web identity token with appropriate provider
+	// 2. Check if the role exists and can be assumed
+	// 3. Generate temporary credentials
+	// 4. Create and store session information
+	// 5. Return response with credentials
+	
+	return nil, fmt.Errorf("AssumeRoleWithWebIdentity not implemented yet")
+}
+
+// AssumeRoleWithCredentials assumes a role using username/password credentials
+func (s *STSService) AssumeRoleWithCredentials(ctx context.Context, request *AssumeRoleWithCredentialsRequest) (*AssumeRoleResponse, error) {
+	if !s.initialized {
+		return nil, fmt.Errorf("STS service not initialized")
+	}
+	
+	if request == nil {
+		return nil, fmt.Errorf("request cannot be nil")
+	}
+	
+	// TODO: Implement AssumeRoleWithCredentials
+	// 1. Validate credentials with the specified provider
+	// 2. Check if the role exists and can be assumed
+	// 3. Generate temporary credentials
+	// 4. Create and store session information
+	// 5. Return response with credentials
+	
+	return nil, fmt.Errorf("AssumeRoleWithCredentials not implemented yet")
+}
+
+// ValidateSessionToken validates a session token and returns session information
+func (s *STSService) ValidateSessionToken(ctx context.Context, sessionToken string) (*SessionInfo, error) {
+	if !s.initialized {
+		return nil, fmt.Errorf("STS service not initialized")
+	}
+	
+	if sessionToken == "" {
+		return nil, fmt.Errorf("session token cannot be empty")
+	}
+	
+	// TODO: Implement session token validation
+	// 1. Parse and verify the session token
+	// 2. Extract session ID from token
+	// 3. Retrieve session from store
+	// 4. Validate expiration and other claims
+	// 5. Return session information
+	
+	return nil, fmt.Errorf("session token validation not implemented yet")
+}
+
+// RevokeSession revokes an active session
+func (s *STSService) RevokeSession(ctx context.Context, sessionToken string) error {
+	if !s.initialized {
+		return fmt.Errorf("STS service not initialized")
+	}
+	
+	if sessionToken == "" {
+		return fmt.Errorf("session token cannot be empty")
+	}
+	
+	// TODO: Implement session revocation
+	// 1. Parse session token to extract session ID
+	// 2. Remove session from store
+	// 3. Add token to revocation list
+	
+	return fmt.Errorf("session revocation not implemented yet")
+}
diff --git a/weed/iam/sts/sts_service_test.go b/weed/iam/sts/sts_service_test.go
new file mode 100644
index 000000000..b92ee1828
--- /dev/null
+++ b/weed/iam/sts/sts_service_test.go
@@ -0,0 +1,389 @@
+package sts
+
+import (
+	"context"
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/seaweedfs/seaweedfs/weed/iam/providers"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// TestSTSServiceInitialization tests STS service initialization
+func TestSTSServiceInitialization(t *testing.T) {
+	tests := []struct {
+		name    string
+		config  *STSConfig
+		wantErr bool
+	}{
+		{
+			name: "valid config",
+			config: &STSConfig{
+				TokenDuration:    time.Hour,
+				MaxSessionLength: time.Hour * 12,
+				Issuer:          "seaweedfs-sts",
+				SigningKey:      []byte("test-signing-key"),
+			},
+			wantErr: false,
+		},
+		{
+			name: "missing signing key",
+			config: &STSConfig{
+				TokenDuration: time.Hour,
+				Issuer:        "seaweedfs-sts",
+			},
+			wantErr: true,
+		},
+		{
+			name: "invalid token duration",
+			config: &STSConfig{
+				TokenDuration: -time.Hour,
+				Issuer:        "seaweedfs-sts",
+				SigningKey:    []byte("test-key"),
+			},
+			wantErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			service := NewSTSService()
+			
+			err := service.Initialize(tt.config)
+			
+			if tt.wantErr {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+				assert.True(t, service.IsInitialized())
+			}
+		})
+	}
+}
+
+// TestAssumeRoleWithWebIdentity tests role assumption with OIDC tokens
+func TestAssumeRoleWithWebIdentity(t *testing.T) {
+	service := setupTestSTSService(t)
+	
+	tests := []struct {
+		name           string
+		roleArn        string
+		webIdentityToken string
+		sessionName    string
+		durationSeconds *int64
+		wantErr        bool
+		expectedSubject string
+	}{
+		{
+			name:             "successful role assumption",
+			roleArn:          "arn:seaweed:iam::role/TestRole",
+			webIdentityToken: "valid-oidc-token",
+			sessionName:      "test-session",
+			durationSeconds:  nil, // Use default
+			wantErr:          false,
+			expectedSubject:  "test-user-id",
+		},
+		{
+			name:             "invalid web identity token",
+			roleArn:          "arn:seaweed:iam::role/TestRole",
+			webIdentityToken: "invalid-token",
+			sessionName:      "test-session",
+			wantErr:          true,
+		},
+		{
+			name:             "non-existent role",
+			roleArn:          "arn:seaweed:iam::role/NonExistentRole",
+			webIdentityToken: "valid-oidc-token",
+			sessionName:      "test-session",
+			wantErr:          true,
+		},
+		{
+			name:             "custom session duration",
+			roleArn:          "arn:seaweed:iam::role/TestRole",
+			webIdentityToken: "valid-oidc-token",
+			sessionName:      "test-session",
+			durationSeconds:  int64Ptr(7200), // 2 hours
+			wantErr:          false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ctx := context.Background()
+			
+			request := &AssumeRoleWithWebIdentityRequest{
+				RoleArn:          tt.roleArn,
+				WebIdentityToken: tt.webIdentityToken,
+				RoleSessionName:  tt.sessionName,
+				DurationSeconds:  tt.durationSeconds,
+			}
+			
+			response, err := service.AssumeRoleWithWebIdentity(ctx, request)
+			
+			if tt.wantErr {
+				assert.Error(t, err)
+				assert.Nil(t, response)
+			} else {
+				assert.NoError(t, err)
+				assert.NotNil(t, response)
+				assert.NotNil(t, response.Credentials)
+				assert.NotNil(t, response.AssumedRoleUser)
+				
+				// Verify credentials
+				creds := response.Credentials
+				assert.NotEmpty(t, creds.AccessKeyId)
+				assert.NotEmpty(t, creds.SecretAccessKey)
+				assert.NotEmpty(t, creds.SessionToken)
+				assert.True(t, creds.Expiration.After(time.Now()))
+				
+				// Verify assumed role user
+				user := response.AssumedRoleUser
+				assert.Equal(t, tt.roleArn, user.AssumedRoleId)
+				assert.Contains(t, user.Arn, tt.sessionName)
+				
+				if tt.expectedSubject != "" {
+					assert.Equal(t, tt.expectedSubject, user.Subject)
+				}
+			}
+		})
+	}
+}
+
+// TestAssumeRoleWithLDAP tests role assumption with LDAP credentials
+func TestAssumeRoleWithLDAP(t *testing.T) {
+	service := setupTestSTSService(t)
+	
+	tests := []struct {
+		name           string
+		roleArn        string
+		username       string
+		password       string
+		sessionName    string
+		wantErr        bool
+	}{
+		{
+			name:        "successful LDAP role assumption",
+			roleArn:     "arn:seaweed:iam::role/LDAPRole",
+			username:    "testuser",
+			password:    "testpass",
+			sessionName: "ldap-session",
+			wantErr:     false,
+		},
+		{
+			name:        "invalid LDAP credentials",
+			roleArn:     "arn:seaweed:iam::role/LDAPRole",
+			username:    "testuser",
+			password:    "wrongpass",
+			sessionName: "ldap-session",
+			wantErr:     true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ctx := context.Background()
+			
+			request := &AssumeRoleWithCredentialsRequest{
+				RoleArn:         tt.roleArn,
+				Username:        tt.username,
+				Password:        tt.password,
+				RoleSessionName: tt.sessionName,
+				ProviderName:    "test-ldap",
+			}
+			
+			response, err := service.AssumeRoleWithCredentials(ctx, request)
+			
+			if tt.wantErr {
+				assert.Error(t, err)
+				assert.Nil(t, response)
+			} else {
+				assert.NoError(t, err)
+				assert.NotNil(t, response)
+				assert.NotNil(t, response.Credentials)
+			}
+		})
+	}
+}
+
+// TestSessionTokenValidation tests session token validation
+func TestSessionTokenValidation(t *testing.T) {
+	service := setupTestSTSService(t)
+	ctx := context.Background()
+	
+	// First, create a session
+	request := &AssumeRoleWithWebIdentityRequest{
+		RoleArn:          "arn:seaweed:iam::role/TestRole",
+		WebIdentityToken: "valid-oidc-token",
+		RoleSessionName:  "test-session",
+	}
+	
+	response, err := service.AssumeRoleWithWebIdentity(ctx, request)
+	require.NoError(t, err)
+	require.NotNil(t, response)
+	
+	sessionToken := response.Credentials.SessionToken
+	
+	tests := []struct {
+		name    string
+		token   string
+		wantErr bool
+	}{
+		{
+			name:    "valid session token",
+			token:   sessionToken,
+			wantErr: false,
+		},
+		{
+			name:    "invalid session token",
+			token:   "invalid-session-token",
+			wantErr: true,
+		},
+		{
+			name:    "empty session token",
+			token:   "",
+			wantErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			session, err := service.ValidateSessionToken(ctx, tt.token)
+			
+			if tt.wantErr {
+				assert.Error(t, err)
+				assert.Nil(t, session)
+			} else {
+				assert.NoError(t, err)
+				assert.NotNil(t, session)
+				assert.Equal(t, "test-session", session.SessionName)
+				assert.Equal(t, "arn:seaweed:iam::role/TestRole", session.RoleArn)
+			}
+		})
+	}
+}
+
+// TestSessionRevocation tests session token revocation
+func TestSessionRevocation(t *testing.T) {
+	service := setupTestSTSService(t)
+	ctx := context.Background()
+	
+	// Create a session first
+	request := &AssumeRoleWithWebIdentityRequest{
+		RoleArn:          "arn:seaweed:iam::role/TestRole",
+		WebIdentityToken: "valid-oidc-token",
+		RoleSessionName:  "test-session",
+	}
+	
+	response, err := service.AssumeRoleWithWebIdentity(ctx, request)
+	require.NoError(t, err)
+	
+	sessionToken := response.Credentials.SessionToken
+	
+	// Verify token is valid before revocation
+	session, err := service.ValidateSessionToken(ctx, sessionToken)
+	assert.NoError(t, err)
+	assert.NotNil(t, session)
+	
+	// Revoke the session
+	err = service.RevokeSession(ctx, sessionToken)
+	assert.NoError(t, err)
+	
+	// Verify token is no longer valid after revocation
+	session, err = service.ValidateSessionToken(ctx, sessionToken)
+	assert.Error(t, err)
+	assert.Nil(t, session)
+}
+
+// Helper functions
+
+func setupTestSTSService(t *testing.T) *STSService {
+	service := NewSTSService()
+	
+	config := &STSConfig{
+		TokenDuration:    time.Hour,
+		MaxSessionLength: time.Hour * 12,
+		Issuer:          "test-sts",
+		SigningKey:      []byte("test-signing-key-32-characters-long"),
+	}
+	
+	err := service.Initialize(config)
+	require.NoError(t, err)
+	
+	// Register test providers
+	mockOIDCProvider := &MockIdentityProvider{
+		name: "test-oidc",
+		validTokens: map[string]*providers.TokenClaims{
+			"valid-oidc-token": {
+				Subject: "test-user-id",
+				Issuer:  "test-issuer",
+				Claims: map[string]interface{}{
+					"email": "test@example.com",
+					"name":  "Test User",
+				},
+			},
+		},
+	}
+	
+	mockLDAPProvider := &MockIdentityProvider{
+		name: "test-ldap",
+		validCredentials: map[string]string{
+			"testuser": "testpass",
+		},
+	}
+	
+	service.RegisterProvider(mockOIDCProvider)
+	service.RegisterProvider(mockLDAPProvider)
+	
+	return service
+}
+
+func int64Ptr(v int64) *int64 {
+	return &v
+}
+
+// Mock identity provider for testing
+type MockIdentityProvider struct {
+	name             string
+	validTokens      map[string]*providers.TokenClaims
+	validCredentials map[string]string
+}
+
+func (m *MockIdentityProvider) Name() string {
+	return m.name
+}
+
+func (m *MockIdentityProvider) Initialize(config interface{}) error {
+	return nil
+}
+
+func (m *MockIdentityProvider) Authenticate(ctx context.Context, token string) (*providers.ExternalIdentity, error) {
+	if claims, exists := m.validTokens[token]; exists {
+		email, _ := claims.GetClaimString("email")
+		name, _ := claims.GetClaimString("name")
+		
+		return &providers.ExternalIdentity{
+			UserID:      claims.Subject,
+			Email:       email,
+			DisplayName: name,
+			Provider:    m.name,
+		}, nil
+	}
+	return nil, fmt.Errorf("invalid token")
+}
+
+func (m *MockIdentityProvider) GetUserInfo(ctx context.Context, userID string) (*providers.ExternalIdentity, error) {
+	return &providers.ExternalIdentity{
+		UserID:   userID,
+		Email:    userID + "@" + m.name + ".com",
+		Provider: m.name,
+	}, nil
+}
+
+func (m *MockIdentityProvider) ValidateToken(ctx context.Context, token string) (*providers.TokenClaims, error) {
+	if claims, exists := m.validTokens[token]; exists {
+		return claims, nil
+	}
+	return nil, fmt.Errorf("invalid token")
+}