refactoring(infra-auth)

2025-08-14 21:21:53 +02:00
parent fde93093b9
commit fa04c16ece
21 changed files with 3031 additions and 44 deletions
@@ -61,7 +61,7 @@ interface AuthenticationService {
        /**
         * The password change was successful.
         */
-        object Success : PasswordChangeResult()
+        data object Success : PasswordChangeResult()

        /**
         * Password change failed.
@@ -73,7 +73,7 @@ interface AuthenticationService {
        /**
         * The new password is too weak.
         */
-        object WeakPassword : PasswordChangeResult()
+        data object WeakPassword : PasswordChangeResult()
    }

    /**
@@ -3,6 +3,8 @@ package at.mocode.infrastructure.auth.client
 import at.mocode.infrastructure.auth.client.model.BerechtigungE
 import com.auth0.jwt.JWT
 import com.auth0.jwt.algorithms.Algorithm
+import com.auth0.jwt.exceptions.JWTVerificationException
+import mu.KotlinLogging
 import java.util.Date
 import kotlin.time.Duration
 import kotlin.time.Duration.Companion.minutes
@@ -16,6 +18,8 @@ class JwtService(
    private val audience: String,
    private val expiration: Duration = 60.minutes
 ) {
+    private val logger = KotlinLogging.logger {}
+
    private val algorithm = Algorithm.HMAC512(secret)
    private val verifier = JWT.require(algorithm)
        .withIssuer(issuer)
@@ -41,50 +45,107 @@ class JwtService(
     * Validates a JWT token.
     *
     * @param token The JWT token to validate
-     * @return True if the token is valid, false otherwise
+     * @return Result with true if the token is valid, or failure with error details
     */
-    fun validateToken(token: String): Boolean {
+    fun validateToken(token: String): Result<Boolean> {
        return try {
            verifier.verify(token)
-            true
-        } catch (_: Exception) {
-            false
+            logger.debug { "JWT token validation successful" }
+            Result.success(true)
+        } catch (e: JWTVerificationException) {
+            logger.warn { "JWT token validation failed: ${e.message}" }
+            Result.failure(e)
+        } catch (e: Exception) {
+            logger.error(e) { "Unexpected error during JWT token validation" }
+            Result.failure(e)
        }
    }

+    /**
+     * Validates a JWT token (legacy method for backward compatibility).
+     *
+     * @param token The JWT token to validate
+     * @return True if the token is valid, false otherwise
+     */
+    @Deprecated("Use validateToken(token: String): Result<Boolean> instead", ReplaceWith("validateToken(token).isSuccess"))
+    fun isValidToken(token: String): Boolean {
+        return validateToken(token).isSuccess
+    }
+
    /**
     * Gets the user ID from a JWT token.
     *
     * @param token The JWT token
+     * @return Result with the user ID, or failure with error details
+     */
+    fun getUserIdFromToken(token: String): Result<String> {
+        return try {
+            val subject = verifier.verify(token).subject
+            if (subject.isNullOrBlank()) {
+                logger.warn { "JWT token has no subject (user ID)" }
+                Result.failure(IllegalStateException("JWT token has no subject"))
+            } else {
+                logger.debug { "Successfully extracted user ID from JWT token" }
+                Result.success(subject)
+            }
+        } catch (e: JWTVerificationException) {
+            logger.warn { "Failed to extract user ID from JWT token: ${e.message}" }
+            Result.failure(e)
+        } catch (e: Exception) {
+            logger.error(e) { "Unexpected error while extracting user ID from JWT token" }
+            Result.failure(e)
+        }
+    }
+
+    /**
+     * Gets the user ID from a JWT token (legacy method for backward compatibility).
+     *
+     * @param token The JWT token
     * @return The user ID, or null if the token is invalid
     */
-    fun getUserIdFromToken(token: String): String? {
-        return try {
-            verifier.verify(token).subject
-        } catch (_: Exception) {
-            null
-        }
+    @Deprecated("Use getUserIdFromToken(token: String): Result<String> instead", ReplaceWith("getUserIdFromToken(token).getOrNull()"))
+    fun getUserId(token: String): String? {
+        return getUserIdFromToken(token).getOrNull()
    }

    /**
     * Gets the permissions from a JWT token.
     *
     * @param token The JWT token
-     * @return The permissions, or an empty list if the token is invalid
+     * @return Result with the permissions, or failure with error details
     */
-    fun getPermissionsFromToken(token: String): List<BerechtigungE> {
+    fun getPermissionsFromToken(token: String): Result<List<BerechtigungE>> {
        return try {
            val decodedJWT = verifier.verify(token)
            val permissionStrings = decodedJWT.getClaim("permissions").asArray(String::class.java)
-            permissionStrings?.mapNotNull {
+            val permissions = permissionStrings?.mapNotNull { permissionString ->
                try {
-                    BerechtigungE.valueOf(it)
-                } catch (_: Exception) {
+                    BerechtigungE.valueOf(permissionString)
+                } catch (_: IllegalArgumentException) {
+                    logger.warn { "Unknown permission in JWT token: $permissionString" }
                    null
                }
            } ?: emptyList()
-        } catch (_: Exception) {
-            emptyList()
+
+            logger.debug { "Successfully extracted ${permissions.size} permissions from JWT token" }
+            Result.success(permissions)
+        } catch (e: JWTVerificationException) {
+            logger.warn { "Failed to extract permissions from JWT token: ${e.message}" }
+            Result.failure(e)
+        } catch (e: Exception) {
+            logger.error(e) { "Unexpected error while extracting permissions from JWT token" }
+            Result.failure(e)
        }
    }
+
+    /**
+     * Gets the permissions from a JWT token (legacy method for backward compatibility).
+     *
+     * @param token The JWT token
+     * @return The permissions, or an empty list if the token is invalid
+     */
+    @Deprecated("Use getPermissionsFromToken(token: String): Result<List<BerechtigungE>> instead", ReplaceWith("getPermissionsFromToken(token).getOrElse { emptyList() }"))
+    fun getPermissions(token: String): List<BerechtigungE> {
+        return getPermissionsFromToken(token).getOrElse { emptyList() }
+    }
 }
@@ -0,0 +1,379 @@
+package at.mocode.infrastructure.auth.client
+
+import at.mocode.infrastructure.auth.client.model.BerechtigungE
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertTimeoutPreemptively
+import java.time.Duration
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.Executors
+import java.util.concurrent.TimeUnit
+import kotlin.system.measureTimeMillis
+import kotlin.time.Duration.Companion.minutes
+
+/**
+ * Performance tests for authentication operations.
+ * These tests ensure that JWT operations meet performance requirements under various load conditions.
+ */
+class AuthPerformanceTest {
+
+    private lateinit var jwtService: JwtService
+    private val testSecret = "a-very-long-and-secure-test-secret-that-is-at-least-512-bits-long-for-hmac512"
+    private val testIssuer = "test-issuer"
+    private val testAudience = "test-audience"
+
+    @BeforeEach
+    fun setUp() {
+        jwtService = JwtService(
+            secret = testSecret,
+            issuer = testIssuer,
+            audience = testAudience,
+            expiration = 60.minutes
+        )
+    }
+
+    // ========== JWT Validation Performance Tests ==========
+
+    @Test
+    fun `JWT validation should complete under 10ms`() {
+        // Arrange
+        val token = jwtService.generateToken("user-123", "testuser", listOf(BerechtigungE.PERSON_READ))
+
+        // Act & Assert - Single validation should be very fast
+        repeat(100) {
+            val timeMs = measureTimeMillis {
+                val result = jwtService.validateToken(token)
+                assertTrue(result.isSuccess)
+            }
+            assertTrue(timeMs < 10, "JWT validation should complete under 10ms (took ${timeMs}ms)")
+        }
+    }
+
+    @Test
+    fun `JWT validation should handle burst load efficiently`() {
+        // Arrange
+        val token = jwtService.generateToken("user-123", "testuser", listOf(BerechtigungE.PERSON_READ))
+        val iterations = 10000
+
+        // Act
+        val timeMs = measureTimeMillis {
+            repeat(iterations) {
+                val result = jwtService.validateToken(token)
+                assertTrue(result.isSuccess)
+            }
+        }
+
+        // Assert - 10,000 validations should complete within reasonable time
+        val avgTimeMs = timeMs.toDouble() / iterations
+        assertTrue(timeMs < 5000, "10,000 validations should complete within 5 seconds (took ${timeMs}ms)")
+        assertTrue(avgTimeMs < 0.5, "Average validation time should be under 0.5ms (was ${avgTimeMs}ms)")
+    }
+
+    @Test
+    fun `JWT validation performance should be consistent`() {
+        // Arrange
+        val token = jwtService.generateToken("user-123", "testuser", listOf(BerechtigungE.PERSON_READ))
+        val measurements = mutableListOf<Long>()
+
+        // Act - Measure multiple batches
+        repeat(10) {
+            val batchTime = measureTimeMillis {
+                repeat(1000) {
+                    val result = jwtService.validateToken(token)
+                    assertTrue(result.isSuccess)
+                }
+            }
+            measurements.add(batchTime)
+        }
+
+        // Assert - Performance should be consistent across batches
+        val avgTime = measurements.average()
+        val maxDeviation = measurements.maxOf { kotlin.math.abs(it - avgTime) }
+        assertTrue(maxDeviation < avgTime * 0.5,
+            "Performance should be consistent (max deviation: ${maxDeviation}ms, avg: ${avgTime}ms)")
+    }
+
+    // ========== Token Generation Performance Tests ==========
+
+    @Test
+    fun `token generation should complete under 5ms`() {
+        // Arrange
+        val permissions = listOf(BerechtigungE.PERSON_READ, BerechtigungE.PFERD_CREATE, BerechtigungE.VEREIN_UPDATE)
+
+        // Act & Assert
+        repeat(100) {
+            val timeMs = measureTimeMillis {
+                val token = jwtService.generateToken("user-$it", "testuser$it", permissions)
+                assertNotNull(token)
+                assertTrue(token.isNotEmpty())
+            }
+            assertTrue(timeMs < 5, "Token generation should complete under 5ms (took ${timeMs}ms)")
+        }
+    }
+
+    @Test
+    fun `token generation should handle high throughput`() {
+        // Arrange
+        val permissions = listOf(BerechtigungE.PERSON_READ, BerechtigungE.VEREIN_READ)
+        val iterations = 5000
+
+        // Act
+        val timeMs = measureTimeMillis {
+            repeat(iterations) {
+                val token = jwtService.generateToken("user-$it", "testuser$it", permissions)
+                assertTrue(token.isNotEmpty())
+            }
+        }
+
+        // Assert - Should generate 5000 tokens within a reasonable time
+        val tokensPerSecond = (iterations * 1000.0) / timeMs
+        assertTrue(tokensPerSecond > 1000,
+            "Should generate at least 1000 tokens/second (achieved ${tokensPerSecond.toInt()}/second)")
+    }
+
+    // ========== Concurrent Access Performance Tests ==========
+
+    @Test
+    fun `token generation should handle concurrent requests`() {
+        // Arrange
+        val threadCount = 10
+        val operationsPerThread = 500
+        val executor = Executors.newFixedThreadPool(threadCount)
+        val latch = CountDownLatch(threadCount)
+        val results = mutableListOf<Boolean>()
+        val errors = mutableListOf<Exception>()
+
+        // Act
+        val totalTime = measureTimeMillis {
+            repeat(threadCount) { threadIndex ->
+                executor.submit {
+                    try {
+                        repeat(operationsPerThread) { opIndex ->
+                            val token = jwtService.generateToken(
+                                "user-$threadIndex-$opIndex",
+                                "testuser$threadIndex",
+                                listOf(BerechtigungE.PERSON_READ)
+                            )
+                            val isValid = jwtService.validateToken(token).isSuccess
+                            synchronized(results) {
+                                results.add(isValid)
+                            }
+                        }
+                    } catch (e: Exception) {
+                        synchronized(errors) {
+                            errors.add(e)
+                        }
+                    } finally {
+                        latch.countDown()
+                    }
+                }
+            }
+            assertTrue(latch.await(30, TimeUnit.SECONDS), "All threads should complete within 30 seconds")
+        }
+
+        executor.shutdown()
+
+        // Assert
+        assertTrue(errors.isEmpty(), "No errors should occur during concurrent operations: ${errors.firstOrNull()}")
+        assertEquals(threadCount * operationsPerThread, results.size)
+        assertTrue(results.all { it }, "All tokens should be valid")
+
+        val operationsPerSecond = (threadCount * operationsPerThread * 1000.0) / totalTime
+        assertTrue(operationsPerSecond > 500,
+            "Should handle at least 500 operations/second under concurrent load (achieved ${operationsPerSecond.toInt()}/second)")
+    }
+
+    @Test
+    fun `token validation should handle concurrent requests`() {
+        // Arrange
+        val token = jwtService.generateToken("user-123", "testuser", listOf(BerechtigungE.PERSON_READ))
+        val threadCount = 20
+        val validationsPerThread = 1000
+        val executor = Executors.newFixedThreadPool(threadCount)
+        val latch = CountDownLatch(threadCount)
+        val results = mutableListOf<Boolean>()
+
+        // Act
+        val totalTime = measureTimeMillis {
+            repeat(threadCount) {
+                executor.submit {
+                    repeat(validationsPerThread) {
+                        val isValid = jwtService.validateToken(token).isSuccess
+                        synchronized(results) {
+                            results.add(isValid)
+                        }
+                    }
+                    latch.countDown()
+                }
+            }
+            assertTrue(latch.await(10, TimeUnit.SECONDS), "All validations should complete within 10 seconds")
+        }
+
+        executor.shutdown()
+
+        // Assert
+        assertEquals(threadCount * validationsPerThread, results.size)
+        assertTrue(results.all { it }, "All validations should succeed")
+
+        val validationsPerSecond = (threadCount * validationsPerThread * 1000.0) / totalTime
+        assertTrue(validationsPerSecond > 10000,
+            "Should handle at least 10,000 validations/second under concurrent load (achieved ${validationsPerSecond.toInt()}/second)")
+    }
+
+    // ========== Memory Usage Performance Tests ==========
+
+    @Test
+    fun `memory usage should be stable under load`() {
+        // Arrange
+        val runtime = Runtime.getRuntime()
+        val initialMemory = runtime.totalMemory() - runtime.freeMemory()
+
+        // Act - Perform many operations to test for memory leaks
+        repeat(10000) {
+            val token = jwtService.generateToken("user-$it", "testuser$it", listOf(BerechtigungE.PERSON_READ))
+            val result = jwtService.validateToken(token)
+            assertTrue(result.isSuccess)
+
+            // Extract data to ensure full processing
+            jwtService.getUserIdFromToken(token)
+            jwtService.getPermissionsFromToken(token)
+        }
+
+        // Force garbage collection
+        System.gc()
+        Thread.sleep(100) // Give GC time to run
+
+        val finalMemory = runtime.totalMemory() - runtime.freeMemory()
+        val memoryIncrease = finalMemory - initialMemory
+
+        // Assert - Memory increase should be reasonable (less than 50MB)
+        assertTrue(memoryIncrease < 50 * 1024 * 1024,
+            "Memory increase should be less than 50MB (was ${memoryIncrease / 1024 / 1024}MB)")
+    }
+
+    // ========== Complex Permissions Performance Tests ==========
+
+    @Test
+    fun `should handle large permission sets efficiently`() {
+        // Arrange - Create a token with all available permissions
+        val allPermissions = BerechtigungE.entries
+
+        // Act & Assert - Generation should still be fast
+        val generationTime = measureTimeMillis {
+            val token = jwtService.generateToken("admin-user", "admin", allPermissions)
+            assertNotNull(token)
+        }
+        assertTrue(generationTime < 100, "Generation with all permissions should be under 100ms")
+
+        // Validation should also be fast
+        val token = jwtService.generateToken("admin-user", "admin", allPermissions)
+        val validationTime = measureTimeMillis {
+            val result = jwtService.validateToken(token)
+            assertTrue(result.isSuccess)
+
+            val permissions = jwtService.getPermissionsFromToken(token).getOrElse { emptyList() }
+            assertEquals(allPermissions.size, permissions.size)
+        }
+        assertTrue(validationTime < 20, "Validation with all permissions should be under 20ms")
+    }
+
+    // ========== Stress Tests ==========
+
+    @Test
+    fun `should handle sustained load without degradation`() {
+        // Arrange
+        val testDurationMs = 5000L // 5 seconds
+        val startTime = System.currentTimeMillis()
+        var operationCount = 0
+        val measurementPoints = mutableListOf<Pair<Long, Int>>() // time, operations per second
+
+        // Act - Sustained load test
+        while (System.currentTimeMillis() - startTime < testDurationMs) {
+            val intervalStart = System.currentTimeMillis()
+            var intervalOperations = 0
+
+            // Run operations for 1-second intervals
+            while (System.currentTimeMillis() - intervalStart < 1000) {
+                val token = jwtService.generateToken("user-$operationCount", "test", listOf(BerechtigungE.PERSON_READ))
+                val isValid = jwtService.validateToken(token).isSuccess
+                assertTrue(isValid)
+                operationCount++
+                intervalOperations++
+            }
+
+            measurementPoints.add(Pair(System.currentTimeMillis() - startTime, intervalOperations))
+        }
+
+        // Assert - Performance should not degrade significantly over time
+        assertTrue(measurementPoints.size >= 4, "Should have at least 4 measurement points")
+
+        val firstHalf = measurementPoints.take(measurementPoints.size / 2).map { it.second }
+        val secondHalf = measurementPoints.drop(measurementPoints.size / 2).map { it.second }
+
+        val firstHalfAvg = firstHalf.average()
+        val secondHalfAvg = secondHalf.average()
+
+        // Performance in the second half should not be significantly worse than the first half
+        assertTrue(secondHalfAvg > firstHalfAvg * 0.8,
+            "Performance should not degrade by more than 20% over time " +
+            "(first half: ${firstHalfAvg.toInt()} ops/sec, second half: ${secondHalfAvg.toInt()} ops/sec)")
+    }
+
+    @Test
+    fun `operations should complete within timeout under extreme load`() {
+        // Arrange - Very high-load scenario
+        val operations = 50000
+
+        // Act & Assert - Should complete within a reasonable timeout
+        assertTimeoutPreemptively(Duration.ofSeconds(30)) {
+            repeat(operations) {
+                val token = jwtService.generateToken("user-$it", "test", listOf(BerechtigungE.PERSON_READ))
+                val result = jwtService.validateToken(token)
+                assertTrue(result.isSuccess)
+            }
+        }
+    }
+
+    // ========== Benchmarking Tests ==========
+
+    @Test
+    fun `benchmark basic JWT operations`() {
+        // This test provides baseline performance metrics for monitoring
+        val iterations = 1000
+
+        // Token Generation Benchmark
+        val generationTime = measureTimeMillis {
+            repeat(iterations) {
+                jwtService.generateToken("user-$it", "test", listOf(BerechtigungE.PERSON_READ))
+            }
+        }
+        val avgGenerationMs = generationTime.toDouble() / iterations
+        println("[DEBUG_LOG] Token generation: ${avgGenerationMs}ms average (${iterations} iterations)")
+
+        // Token Validation Benchmark
+        val token = jwtService.generateToken("benchmark-user", "test", listOf(BerechtigungE.PERSON_READ))
+        val validationTime = measureTimeMillis {
+            repeat(iterations) {
+                jwtService.validateToken(token)
+            }
+        }
+        val avgValidationMs = validationTime.toDouble() / iterations
+        println("[DEBUG_LOG] Token validation: ${avgValidationMs}ms average (${iterations} iterations)")
+
+        // Data Extraction Benchmark
+        val extractionTime = measureTimeMillis {
+            repeat(iterations) {
+                jwtService.getUserIdFromToken(token)
+                jwtService.getPermissionsFromToken(token)
+            }
+        }
+        val avgExtractionMs = extractionTime.toDouble() / iterations
+        println("[DEBUG_LOG] Data extraction: ${avgExtractionMs}ms average (${iterations} iterations)")
+
+        // Performance should meet baseline requirements
+        assertTrue(avgGenerationMs < 2.0, "Token generation should average under 2ms")
+        assertTrue(avgValidationMs < 1.0, "Token validation should average under 1ms")
+        assertTrue(avgExtractionMs < 1.0, "Data extraction should average under 1ms")
+    }
+}
@@ -0,0 +1,339 @@
+package at.mocode.infrastructure.auth.client
+
+import at.mocode.infrastructure.auth.client.model.BerechtigungE
+import com.benasher44.uuid.uuid4
+import io.mockk.coEvery
+import io.mockk.mockk
+import kotlinx.coroutines.test.runTest
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import java.time.LocalDateTime
+
+/**
+ * Tests for the AuthenticationService interface using mocks.
+ * These tests verify the contract and behavior expectations without requiring real implementations.
+ */
+class AuthenticationServiceTest {
+
+    private lateinit var authService: AuthenticationService
+    private val testUserId = uuid4()
+    private val testPersonId = uuid4()
+
+    @BeforeEach
+    fun setUp() {
+        authService = mockk<AuthenticationService>()
+    }
+
+    // ========== Authentication Tests ==========
+
+    @Test
+    fun `authenticate should return Success for valid credentials`() = runTest {
+        // Arrange
+        val username = "testuser"
+        val password = "validpassword"
+        val expectedUser = AuthenticationService.AuthenticatedUser(
+            userId = testUserId,
+            personId = testPersonId,
+            username = username,
+            email = "test@example.com",
+            permissions = listOf(BerechtigungE.PERSON_READ, BerechtigungE.VEREIN_READ)
+        )
+        val expectedToken = "valid.jwt.token"
+
+        coEvery { authService.authenticate(username, password) } returns
+            AuthenticationService.AuthResult.Success(expectedToken, expectedUser)
+
+        // Act
+        val result = authService.authenticate(username, password)
+
+        // Assert
+        assertTrue(result is AuthenticationService.AuthResult.Success)
+        val successResult = result as AuthenticationService.AuthResult.Success
+        assertEquals(expectedToken, successResult.token)
+        assertEquals(expectedUser.userId, successResult.user.userId)
+        assertEquals(expectedUser.username, successResult.user.username)
+        assertEquals(expectedUser.email, successResult.user.email)
+        assertEquals(2, successResult.user.permissions.size)
+        assertTrue(successResult.user.permissions.contains(BerechtigungE.PERSON_READ))
+        assertTrue(successResult.user.permissions.contains(BerechtigungE.VEREIN_READ))
+    }
+
+    @Test
+    fun `authenticate should return Failure for invalid credentials`() = runTest {
+        // Arrange
+        val username = "testuser"
+        val password = "wrongpassword"
+        val expectedReason = "Invalid username or password"
+
+        coEvery { authService.authenticate(username, password) } returns
+            AuthenticationService.AuthResult.Failure(expectedReason)
+
+        // Act
+        val result = authService.authenticate(username, password)
+
+        // Assert
+        assertTrue(result is AuthenticationService.AuthResult.Failure)
+        val failureResult = result as AuthenticationService.AuthResult.Failure
+        assertEquals(expectedReason, failureResult.reason)
+    }
+
+    @Test
+    fun `authenticate should return Locked for locked accounts`() = runTest {
+        // Arrange
+        val username = "lockeduser"
+        val password = "password"
+        val lockedUntil = LocalDateTime.now().plusHours(1)
+
+        coEvery { authService.authenticate(username, password) } returns
+            AuthenticationService.AuthResult.Locked(lockedUntil)
+
+        // Act
+        val result = authService.authenticate(username, password)
+
+        // Assert
+        assertTrue(result is AuthenticationService.AuthResult.Locked)
+        val lockedResult = result as AuthenticationService.AuthResult.Locked
+        assertEquals(lockedUntil, lockedResult.lockedUntil)
+    }
+
+    @Test
+    fun `authenticate should handle empty username gracefully`() = runTest {
+        // Arrange
+        val emptyUsername = ""
+        val password = "password"
+
+        coEvery { authService.authenticate(emptyUsername, password) } returns
+            AuthenticationService.AuthResult.Failure("Username cannot be empty")
+
+        // Act
+        val result = authService.authenticate(emptyUsername, password)
+
+        // Assert
+        assertTrue(result is AuthenticationService.AuthResult.Failure)
+        val failureResult = result as AuthenticationService.AuthResult.Failure
+        assertTrue(failureResult.reason.contains("Username"))
+    }
+
+    @Test
+    fun `authenticate should handle empty password gracefully`() = runTest {
+        // Arrange
+        val username = "testuser"
+        val emptyPassword = ""
+
+        coEvery { authService.authenticate(username, emptyPassword) } returns
+            AuthenticationService.AuthResult.Failure("Password cannot be empty")
+
+        // Act
+        val result = authService.authenticate(username, emptyPassword)
+
+        // Assert
+        assertTrue(result is AuthenticationService.AuthResult.Failure)
+        val failureResult = result as AuthenticationService.AuthResult.Failure
+        assertTrue(failureResult.reason.contains("Password"))
+    }
+
+    // ========== Password Change Tests ==========
+
+    @Test
+    fun `changePassword should return Success for valid password change`() = runTest {
+        // Arrange
+        val currentPassword = "oldpassword"
+        val newPassword = "newpassword123"
+
+        coEvery { authService.changePassword(testUserId, currentPassword, newPassword) } returns
+            AuthenticationService.PasswordChangeResult.Success
+
+        // Act
+        val result = authService.changePassword(testUserId, currentPassword, newPassword)
+
+        // Assert
+        assertTrue(result is AuthenticationService.PasswordChangeResult.Success)
+    }
+
+    @Test
+    fun `changePassword should validate current password`() = runTest {
+        // Arrange
+        val wrongCurrentPassword = "wrongpassword"
+        val newPassword = "newpassword123"
+
+        coEvery { authService.changePassword(testUserId, wrongCurrentPassword, newPassword) } returns
+            AuthenticationService.PasswordChangeResult.Failure("Current password is incorrect")
+
+        // Act
+        val result = authService.changePassword(testUserId, wrongCurrentPassword, newPassword)
+
+        // Assert
+        assertTrue(result is AuthenticationService.PasswordChangeResult.Failure)
+        val failureResult = result as AuthenticationService.PasswordChangeResult.Failure
+        assertTrue(failureResult.reason.contains("Current password"))
+    }
+
+    @Test
+    fun `changePassword should reject weak passwords`() = runTest {
+        // Arrange
+        val currentPassword = "oldpassword"
+        val weakPassword = "123" // Too short and simple
+
+        coEvery { authService.changePassword(testUserId, currentPassword, weakPassword) } returns
+            AuthenticationService.PasswordChangeResult.WeakPassword
+
+        // Act
+        val result = authService.changePassword(testUserId, currentPassword, weakPassword)
+
+        // Assert
+        assertTrue(result is AuthenticationService.PasswordChangeResult.WeakPassword)
+    }
+
+    @Test
+    fun `changePassword should handle concurrent modifications`() = runTest {
+        // Arrange
+        val currentPassword = "oldpassword"
+        val newPassword = "newpassword123"
+
+        coEvery { authService.changePassword(testUserId, currentPassword, newPassword) } returns
+            AuthenticationService.PasswordChangeResult.Failure("User was modified concurrently")
+
+        // Act
+        val result = authService.changePassword(testUserId, currentPassword, newPassword)
+
+        // Assert
+        assertTrue(result is AuthenticationService.PasswordChangeResult.Failure)
+        val failureResult = result as AuthenticationService.PasswordChangeResult.Failure
+        assertTrue(failureResult.reason.contains("concurrently"))
+    }
+
+    @Test
+    fun `changePassword should handle user not found scenario`() = runTest {
+        // Arrange
+        val nonExistentUserId = uuid4()
+        val currentPassword = "password"
+        val newPassword = "newpassword123"
+
+        coEvery { authService.changePassword(nonExistentUserId, currentPassword, newPassword) } returns
+            AuthenticationService.PasswordChangeResult.Failure("User not found")
+
+        // Act
+        val result = authService.changePassword(nonExistentUserId, currentPassword, newPassword)
+
+        // Assert
+        assertTrue(result is AuthenticationService.PasswordChangeResult.Failure)
+        val failureResult = result as AuthenticationService.PasswordChangeResult.Failure
+        assertTrue(failureResult.reason.contains("not found"))
+    }
+
+    // ========== AuthenticatedUser Model Tests ==========
+
+    @Test
+    fun `AuthenticatedUser should properly encapsulate user data`() {
+        // Arrange & Act
+        val user = AuthenticationService.AuthenticatedUser(
+            userId = testUserId,
+            personId = testPersonId,
+            username = "testuser",
+            email = "test@example.com",
+            permissions = listOf(BerechtigungE.PERSON_READ, BerechtigungE.PFERD_CREATE)
+        )
+
+        // Assert
+        assertEquals(testUserId, user.userId)
+        assertEquals(testPersonId, user.personId)
+        assertEquals("testuser", user.username)
+        assertEquals("test@example.com", user.email)
+        assertEquals(2, user.permissions.size)
+        assertTrue(user.permissions.contains(BerechtigungE.PERSON_READ))
+        assertTrue(user.permissions.contains(BerechtigungE.PFERD_CREATE))
+    }
+
+    @Test
+    fun `AuthenticatedUser should handle empty permissions list`() {
+        // Arrange & Act
+        val user = AuthenticationService.AuthenticatedUser(
+            userId = testUserId,
+            personId = testPersonId,
+            username = "limiteduser",
+            email = "limited@example.com",
+            permissions = emptyList()
+        )
+
+        // Assert
+        assertTrue(user.permissions.isEmpty())
+        assertEquals("limiteduser", user.username)
+    }
+
+    // ========== Result Type Pattern Tests ==========
+
+    @Test
+    fun `AuthResult sealed class should support pattern matching`() = runTest {
+        // Arrange
+        val successResult = AuthenticationService.AuthResult.Success(
+            "token",
+            AuthenticationService.AuthenticatedUser(
+                testUserId, testPersonId, "user", "email@test.com", emptyList()
+            )
+        )
+        val failureResult = AuthenticationService.AuthResult.Failure("Failed")
+        val lockedResult = AuthenticationService.AuthResult.Locked(LocalDateTime.now())
+
+        // Act & Assert
+        when (successResult) {
+            is AuthenticationService.AuthResult.Success -> {
+                assertNotNull(successResult.token)
+                assertNotNull(successResult.user)
+            }
+            is AuthenticationService.AuthResult.Failure -> fail("Should not be failure")
+            is AuthenticationService.AuthResult.Locked -> fail("Should not be locked")
+        }
+
+        when (failureResult) {
+            is AuthenticationService.AuthResult.Success -> fail("Should not be success")
+            is AuthenticationService.AuthResult.Failure -> {
+                assertEquals("Failed", failureResult.reason)
+            }
+            is AuthenticationService.AuthResult.Locked -> fail("Should not be locked")
+        }
+
+        when (lockedResult) {
+            is AuthenticationService.AuthResult.Success -> fail("Should not be success")
+            is AuthenticationService.AuthResult.Failure -> fail("Should not be failure")
+            is AuthenticationService.AuthResult.Locked -> {
+                assertNotNull(lockedResult.lockedUntil)
+            }
+        }
+    }
+
+    @Test
+    fun `PasswordChangeResult sealed class should support pattern matching`() = runTest {
+        // Arrange
+        val successResult = AuthenticationService.PasswordChangeResult.Success
+        val failureResult = AuthenticationService.PasswordChangeResult.Failure("Failed")
+        val weakPasswordResult = AuthenticationService.PasswordChangeResult.WeakPassword
+
+        // Act & Assert
+        when (successResult) {
+            is AuthenticationService.PasswordChangeResult.Success -> {
+                // Success case - no additional data
+                assertTrue(true)
+            }
+            is AuthenticationService.PasswordChangeResult.Failure -> fail("Should not be failure")
+            is AuthenticationService.PasswordChangeResult.WeakPassword -> fail("Should not be weak password")
+        }
+
+        when (failureResult) {
+            is AuthenticationService.PasswordChangeResult.Success -> fail("Should not be success")
+            is AuthenticationService.PasswordChangeResult.Failure -> {
+                assertEquals("Failed", failureResult.reason)
+            }
+            is AuthenticationService.PasswordChangeResult.WeakPassword -> fail("Should not be weak password")
+        }
+
+        when (weakPasswordResult) {
+            is AuthenticationService.PasswordChangeResult.Success -> fail("Should not be success")
+            is AuthenticationService.PasswordChangeResult.Failure -> fail("Should not be failure")
+            is AuthenticationService.PasswordChangeResult.WeakPassword -> {
+                // Weak password case - no additional data
+                assertTrue(true)
+            }
+        }
+    }
+}
@@ -0,0 +1,299 @@
+package at.mocode.infrastructure.auth.client
+
+import at.mocode.infrastructure.auth.client.model.BerechtigungE
+import com.auth0.jwt.exceptions.JWTVerificationException
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import kotlin.time.Duration.Companion.minutes
+import kotlin.time.Duration.Companion.seconds
+
+/**
+ * Extended tests for JwtService focusing on Result-based APIs, edge cases, and security scenarios.
+ */
+class JwtServiceExtendedTest {
+
+    private lateinit var jwtService: JwtService
+    private val testSecret = "a-very-long-and-secure-test-secret-that-is-at-least-512-bits-long-for-hmac512"
+    private val testIssuer = "test-issuer"
+    private val testAudience = "test-audience"
+
+    @BeforeEach
+    fun setUp() {
+        jwtService = JwtService(
+            secret = testSecret,
+            issuer = testIssuer,
+            audience = testAudience,
+            expiration = 60.minutes
+        )
+    }
+
+    // ========== Result API Tests ==========
+
+    @Test
+    fun `validateToken should return Success with true for valid token`() {
+        // Arrange
+        val token = jwtService.generateToken("user-123", "testuser", listOf(BerechtigungE.PERSON_READ))
+
+        // Act
+        val result = jwtService.validateToken(token)
+
+        // Assert
+        assertTrue(result.isSuccess)
+        assertEquals(true, result.getOrNull())
+    }
+
+    @Test
+    fun `validateToken should return Failure for malformed token`() {
+        // Arrange
+        val malformedToken = "this.is.not.a.valid.jwt.token"
+
+        // Act
+        val result = jwtService.validateToken(malformedToken)
+
+        // Assert
+        assertTrue(result.isFailure)
+        assertInstanceOf(JWTVerificationException::class.java, result.exceptionOrNull())
+    }
+
+    @Test
+    fun `validateToken should return Failure for token with wrong issuer`() {
+        // Arrange
+        val wrongIssuerService = JwtService(testSecret, "wrong-issuer", testAudience)
+        val token = wrongIssuerService.generateToken("user-123", "test", emptyList())
+
+        // Act
+        val result = jwtService.validateToken(token)
+
+        // Assert
+        assertTrue(result.isFailure)
+        assertInstanceOf(JWTVerificationException::class.java, result.exceptionOrNull())
+    }
+
+    @Test
+    fun `validateToken should return Failure for token with wrong audience`() {
+        // Arrange
+        val wrongAudienceService = JwtService(testSecret, testIssuer, "wrong-audience")
+        val token = wrongAudienceService.generateToken("user-123", "test", emptyList())
+
+        // Act
+        val result = jwtService.validateToken(token)
+
+        // Assert
+        assertTrue(result.isFailure)
+        assertInstanceOf(JWTVerificationException::class.java, result.exceptionOrNull())
+    }
+
+    @Test
+    fun `validateToken should return Failure for expired token`() {
+        // Arrange
+        val expiredService = JwtService(testSecret, testIssuer, testAudience, expiration = (-10).seconds)
+        val token = expiredService.generateToken("user-123", "test", emptyList())
+
+        // Act
+        val result = jwtService.validateToken(token)
+
+        // Assert
+        assertTrue(result.isFailure)
+        assertInstanceOf(JWTVerificationException::class.java, result.exceptionOrNull())
+    }
+
+    // ========== getUserIdFromToken Result API Tests ==========
+
+    @Test
+    fun `getUserIdFromToken should return Success with user ID for valid token`() {
+        // Arrange
+        val userId = "user-12345"
+        val token = jwtService.generateToken(userId, "testuser", emptyList())
+
+        // Act
+        val result = jwtService.getUserIdFromToken(token)
+
+        // Assert
+        assertTrue(result.isSuccess)
+        assertEquals(userId, result.getOrNull())
+    }
+
+    @Test
+    fun `getUserIdFromToken should return Failure for invalid token`() {
+        // Arrange
+        val invalidToken = "invalid.jwt.token"
+
+        // Act
+        val result = jwtService.getUserIdFromToken(invalidToken)
+
+        // Assert
+        assertTrue(result.isFailure)
+        assertInstanceOf(JWTVerificationException::class.java, result.exceptionOrNull())
+    }
+
+    @Test
+    fun `getUserIdFromToken should handle missing subject claim`() {
+        // Note: This test verifies that empty/blank subject claims are properly rejected for security
+        val token = jwtService.generateToken("", "testuser", emptyList())
+
+        val result = jwtService.getUserIdFromToken(token)
+
+        // Empty subject should be rejected for security reasons
+        assertTrue(result.isFailure)
+        assertInstanceOf(IllegalStateException::class.java, result.exceptionOrNull())
+        assertTrue(result.exceptionOrNull()!!.message!!.contains("no subject"))
+    }
+
+    // ========== getPermissionsFromToken Result API Tests ==========
+
+    @Test
+    fun `getPermissionsFromToken should return Success with permissions for valid token`() {
+        // Arrange
+        val permissions = listOf(BerechtigungE.PERSON_READ, BerechtigungE.PFERD_CREATE, BerechtigungE.VEREIN_UPDATE)
+        val token = jwtService.generateToken("user-123", "testuser", permissions)
+
+        // Act
+        val result = jwtService.getPermissionsFromToken(token)
+
+        // Assert
+        assertTrue(result.isSuccess)
+        val extractedPermissions = result.getOrNull()!!
+        assertEquals(3, extractedPermissions.size)
+        assertTrue(extractedPermissions.containsAll(permissions))
+    }
+
+    @Test
+    fun `getPermissionsFromToken should return Failure for invalid token`() {
+        // Arrange
+        val invalidToken = "invalid.jwt.token"
+
+        // Act
+        val result = jwtService.getPermissionsFromToken(invalidToken)
+
+        // Assert
+        assertTrue(result.isFailure)
+        assertInstanceOf(JWTVerificationException::class.java, result.exceptionOrNull())
+    }
+
+    @Test
+    fun `getPermissionsFromToken should return empty list for token without permissions`() {
+        // Arrange
+        val token = jwtService.generateToken("user-123", "testuser", emptyList())
+
+        // Act
+        val result = jwtService.getPermissionsFromToken(token)
+
+        // Assert
+        assertTrue(result.isSuccess)
+        val permissions = result.getOrNull()!!
+        assertTrue(permissions.isEmpty())
+    }
+
+    @Test
+    fun `getPermissionsFromToken should ignore unknown permissions gracefully`() {
+        // This test simulates a token with permissions that don't exist in the enum
+        // In practice, this would require manually crafting a JWT, so this tests the enum parsing logic
+        val permissions = listOf(BerechtigungE.PERSON_READ)
+        val token = jwtService.generateToken("user-123", "testuser", permissions)
+
+        val result = jwtService.getPermissionsFromToken(token)
+
+        assertTrue(result.isSuccess)
+        val extractedPermissions = result.getOrNull()!!
+        assertEquals(1, extractedPermissions.size)
+        assertEquals(BerechtigungE.PERSON_READ, extractedPermissions[0])
+    }
+
+    // ========== Token Generation Tests ==========
+
+    @Test
+    fun `generateToken should create tokens with correct expiration time`() {
+        // Arrange
+        val shortExpirationService = JwtService(testSecret, testIssuer, testAudience, expiration = 5.seconds)
+        val token = shortExpirationService.generateToken("user-123", "test", emptyList())
+
+        // Act - Validate immediately (should be valid)
+        val immediateResult = shortExpirationService.validateToken(token)
+
+        // Wait and validate again (should be expired) - using Thread.sleep is acceptable for this specific test
+        Thread.sleep(6000) // 6 seconds
+        val delayedResult = shortExpirationService.validateToken(token)
+
+        // Assert
+        assertTrue(immediateResult.isSuccess, "Token should be valid immediately after creation")
+        assertTrue(delayedResult.isFailure, "Token should be expired after waiting")
+    }
+
+    // ========== Legacy Method Backward Compatibility Tests ==========
+
+    @Test
+    fun `legacy methods should maintain backward compatibility`() {
+        // Arrange
+        val userId = "user-123"
+        val permissions = listOf(BerechtigungE.PERSON_READ, BerechtigungE.PFERD_CREATE)
+        val token = jwtService.generateToken(userId, "testuser", permissions)
+
+        // Act & Assert - Legacy methods should still work
+        @Suppress("DEPRECATION")
+        assertTrue(jwtService.isValidToken(token))
+
+        @Suppress("DEPRECATION")
+        assertEquals(userId, jwtService.getUserId(token))
+
+        @Suppress("DEPRECATION")
+        val legacyPermissions = jwtService.getPermissions(token)
+        assertEquals(2, legacyPermissions.size)
+        assertTrue(legacyPermissions.containsAll(permissions))
+    }
+
+    @Test
+    fun `legacy methods should handle invalid tokens gracefully`() {
+        // Arrange
+        val invalidToken = "invalid.token"
+
+        // Act & Assert - Legacy methods should handle errors gracefully
+        @Suppress("DEPRECATION")
+        assertFalse(jwtService.isValidToken(invalidToken))
+
+        @Suppress("DEPRECATION")
+        assertNull(jwtService.getUserId(invalidToken))
+
+        @Suppress("DEPRECATION")
+        val permissions = jwtService.getPermissions(invalidToken)
+        assertTrue(permissions.isEmpty())
+    }
+
+    // ========== Security Edge Cases ==========
+
+    @Test
+    fun `should reject tokens with tampered signatures`() {
+        // Arrange
+        val validToken = jwtService.generateToken("user-123", "testuser", emptyList())
+        val tamperedToken = validToken.dropLast(5) + "TAMPR"
+
+        // Act
+        val result = jwtService.validateToken(tamperedToken)
+
+        // Assert
+        assertTrue(result.isFailure)
+        assertInstanceOf(JWTVerificationException::class.java, result.exceptionOrNull())
+    }
+
+    @Test
+    fun `should handle empty token gracefully`() {
+        // Act
+        val result = jwtService.validateToken("")
+
+        // Assert
+        assertTrue(result.isFailure)
+        assertNotNull(result.exceptionOrNull())
+    }
+
+    @Test
+    fun `should handle null-like values in token validation`() {
+        // Arrange
+        val nullLikeTokens = listOf("null", "undefined", " ", "\t", "\n")
+
+        // Act & Assert
+        nullLikeTokens.forEach { token ->
+            val result = jwtService.validateToken(token)
+            assertTrue(result.isFailure, "Token '$token' should be rejected")
+        }
+    }
+}
@@ -35,10 +35,10 @@ class JwtServiceTest {

        // Assert
        assertNotNull(token)
-        assertTrue(jwtService.validateToken(token))
-        assertEquals(userId, jwtService.getUserIdFromToken(token))
+        assertTrue(jwtService.validateToken(token).isSuccess)
+        assertEquals(userId, jwtService.getUserIdFromToken(token).getOrNull())

-        val extractedPermissions = jwtService.getPermissionsFromToken(token)
+        val extractedPermissions = jwtService.getPermissionsFromToken(token).getOrElse { emptyList() }
        assertEquals(2, extractedPermissions.size)
        assertTrue(extractedPermissions.contains(BerechtigungE.PERSON_READ))
        assertTrue(extractedPermissions.contains(BerechtigungE.PFERD_CREATE))
@@ -51,20 +51,18 @@ class JwtServiceTest {
        val token = otherService.generateToken("user-123", "test", emptyList())

        // Act & Assert
-        assertFalse(jwtService.validateToken(token))
+        assertFalse(jwtService.validateToken(token).isSuccess)
    }

    @Test
    fun `validateToken should return false for expired token`() {
        // Arrange
        val expiredService =
-            JwtService(testSecret, testIssuer, testAudience, expiration = (-1).seconds) // läuft sofort ab
+            JwtService(testSecret, testIssuer, testAudience, expiration = (-10).seconds) // bereits abgelaufen
        val token = expiredService.generateToken("user-123", "test", emptyList())

        // Act & Assert
-        // möglicherweise ist eine kleine Verzögerung nötig, um sicherzustellen, dass die Zeitstempel unterschiedlich sind
-        Thread.sleep(10)
-        assertFalse(jwtService.validateToken(token))
+        assertFalse(jwtService.validateToken(token).isSuccess)
    }

    @Test
@@ -73,7 +71,7 @@ class JwtServiceTest {
        val invalidToken = "this.is.not.a.valid.token"

        // Act
-        val permissions = jwtService.getPermissionsFromToken(invalidToken)
+        val permissions = jwtService.getPermissionsFromToken(invalidToken).getOrElse { emptyList() }

        // Assert
        assertTrue(permissions.isEmpty())
@@ -0,0 +1,331 @@
+package at.mocode.infrastructure.auth.client
+
+import at.mocode.infrastructure.auth.client.model.BerechtigungE
+import com.auth0.jwt.exceptions.JWTVerificationException
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import kotlin.time.Duration.Companion.minutes
+import kotlin.time.Duration.Companion.seconds
+
+/**
+ * Comprehensive tests for the Result-based APIs in the auth module.
+ * Tests focus on Result type behavior, error handling, and API consistency.
+ */
+class ResultApiTest {
+
+    private lateinit var jwtService: JwtService
+    private val testSecret = "a-very-long-and-secure-test-secret-that-is-at-least-512-bits-long-for-hmac512"
+    private val testIssuer = "test-issuer"
+    private val testAudience = "test-audience"
+
+    @BeforeEach
+    fun setUp() {
+        jwtService = JwtService(
+            secret = testSecret,
+            issuer = testIssuer,
+            audience = testAudience,
+            expiration = 60.minutes
+        )
+    }
+
+    // ========== Result Success Cases Tests ==========
+
+    @Test
+    fun `Result success cases should provide correct values`() {
+        // Arrange
+        val userId = "user-12345"
+        val permissions = listOf(BerechtigungE.PERSON_READ, BerechtigungE.PFERD_CREATE)
+        val token = jwtService.generateToken(userId, "testuser", permissions)
+
+        // Act - Test all Result-based APIs
+        val validateResult = jwtService.validateToken(token)
+        val userIdResult = jwtService.getUserIdFromToken(token)
+        val permissionsResult = jwtService.getPermissionsFromToken(token)
+
+        // Assert - All should be successful
+        assertTrue(validateResult.isSuccess)
+        assertTrue(validateResult.isFailure.not())
+        assertEquals(true, validateResult.getOrNull())
+        assertNull(validateResult.exceptionOrNull())
+
+        assertTrue(userIdResult.isSuccess)
+        assertTrue(userIdResult.isFailure.not())
+        assertEquals(userId, userIdResult.getOrNull())
+        assertNull(userIdResult.exceptionOrNull())
+
+        assertTrue(permissionsResult.isSuccess)
+        assertTrue(permissionsResult.isFailure.not())
+        val extractedPermissions = permissionsResult.getOrNull()!!
+        assertEquals(2, extractedPermissions.size)
+        assertTrue(extractedPermissions.containsAll(permissions))
+        assertNull(permissionsResult.exceptionOrNull())
+    }
+
+    @Test
+    fun `Result getOrElse should work correctly for success cases`() {
+        // Arrange
+        val token = jwtService.generateToken("user-123", "test", listOf(BerechtigungE.VEREIN_READ))
+
+        // Act & Assert
+        val isValid = jwtService.validateToken(token).getOrElse { false }
+        assertTrue(isValid)
+
+        val userId = jwtService.getUserIdFromToken(token).getOrElse { "default" }
+        assertEquals("user-123", userId)
+
+        val permissions = jwtService.getPermissionsFromToken(token).getOrElse { emptyList() }
+        assertEquals(1, permissions.size)
+        assertEquals(BerechtigungE.VEREIN_READ, permissions[0])
+    }
+
+    // ========== Result Failure Cases Tests ==========
+
+    @Test
+    fun `Result failure cases should contain meaningful error messages`() {
+        // Arrange
+        val invalidToken = "invalid.jwt.token"
+
+        // Act
+        val validateResult = jwtService.validateToken(invalidToken)
+        val userIdResult = jwtService.getUserIdFromToken(invalidToken)
+        val permissionsResult = jwtService.getPermissionsFromToken(invalidToken)
+
+        // Assert - All should be failures with proper exception types
+        assertTrue(validateResult.isFailure)
+        assertTrue(validateResult.isSuccess.not())
+        assertNull(validateResult.getOrNull())
+        assertInstanceOf(JWTVerificationException::class.java, validateResult.exceptionOrNull())
+
+        assertTrue(userIdResult.isFailure)
+        assertTrue(userIdResult.isSuccess.not())
+        assertNull(userIdResult.getOrNull())
+        assertInstanceOf(JWTVerificationException::class.java, userIdResult.exceptionOrNull())
+
+        assertTrue(permissionsResult.isFailure)
+        assertTrue(permissionsResult.isSuccess.not())
+        assertNull(permissionsResult.getOrNull())
+        assertInstanceOf(JWTVerificationException::class.java, permissionsResult.exceptionOrNull())
+    }
+
+    @Test
+    fun `Result getOrElse should work correctly for failure cases`() {
+        // Arrange
+        val invalidToken = "invalid.token"
+
+        // Act & Assert
+        val isValid = jwtService.validateToken(invalidToken).getOrElse { false }
+        assertFalse(isValid)
+
+        val userId = jwtService.getUserIdFromToken(invalidToken).getOrElse { "default-user" }
+        assertEquals("default-user", userId)
+
+        val permissions = jwtService.getPermissionsFromToken(invalidToken).getOrElse { emptyList() }
+        assertTrue(permissions.isEmpty())
+    }
+
+    @Test
+    fun `Result getOrDefault should handle different default types`() {
+        // Arrange
+        val invalidToken = "malformed.jwt"
+
+        // Act & Assert - Test various default value types
+        val defaultBoolean = jwtService.validateToken(invalidToken).getOrElse { true }
+        assertTrue(defaultBoolean)
+
+        val defaultString = jwtService.getUserIdFromToken(invalidToken).getOrElse { "anonymous" }
+        assertEquals("anonymous", defaultString)
+
+        val defaultList = jwtService.getPermissionsFromToken(invalidToken).getOrElse { listOf(BerechtigungE.PERSON_READ) }
+        assertEquals(1, defaultList.size)
+        assertEquals(BerechtigungE.PERSON_READ, defaultList[0])
+    }
+
+    // ========== Result Chaining Tests ==========
+
+    @Test
+    fun `Result chaining should work correctly`() {
+        // Arrange
+        val token = jwtService.generateToken("user-123", "test", listOf(BerechtigungE.PERSON_READ))
+
+        // Act - Chain Result operations
+        val chainedResult = jwtService.validateToken(token)
+            .map { isValid -> if (isValid) "VALID" else "INVALID" }
+
+        val userChainedResult = jwtService.getUserIdFromToken(token)
+            .map { userId -> "User: $userId" }
+
+        val permissionChainedResult = jwtService.getPermissionsFromToken(token)
+            .map { permissions -> permissions.map { it.name } }
+
+        // Assert
+        assertTrue(chainedResult.isSuccess)
+        assertEquals("VALID", chainedResult.getOrNull())
+
+        assertTrue(userChainedResult.isSuccess)
+        assertEquals("User: user-123", userChainedResult.getOrNull())
+
+        assertTrue(permissionChainedResult.isSuccess)
+        val permissionNames = permissionChainedResult.getOrNull()!!
+        assertEquals(1, permissionNames.size)
+        assertEquals("PERSON_READ", permissionNames[0])
+    }
+
+    @Test
+    fun `Result chaining should handle failures correctly`() {
+        // Arrange
+        val invalidToken = "bad.token"
+
+        // Act - Chain operations that will fail
+        val chainedResult = jwtService.validateToken(invalidToken)
+            .map { isValid -> "This should not be called" }
+
+        val userChainedResult = jwtService.getUserIdFromToken(invalidToken)
+            .map { userId -> "User: $userId" }
+
+        // Assert - Chained operations should not execute on failure
+        assertTrue(chainedResult.isFailure)
+        assertNull(chainedResult.getOrNull())
+
+        assertTrue(userChainedResult.isFailure)
+        assertNull(userChainedResult.getOrNull())
+    }
+
+    // ========== Exception Handling Consistency Tests ==========
+
+    @Test
+    fun `Exception handling should be consistent across all Result methods`() {
+        // Test various types of invalid tokens
+        val testCases = listOf(
+            "malformed.token",
+            "",
+            "too.short",
+            "way.too.many.parts.in.this.token.structure",
+            "null.claims.signature"
+        )
+
+        testCases.forEach { invalidToken ->
+            // All methods should handle the same invalid input consistently
+            val validateResult = jwtService.validateToken(invalidToken)
+            val userIdResult = jwtService.getUserIdFromToken(invalidToken)
+            val permissionsResult = jwtService.getPermissionsFromToken(invalidToken)
+
+            // All should fail
+            assertTrue(validateResult.isFailure, "validateToken should fail for: $invalidToken")
+            assertTrue(userIdResult.isFailure, "getUserIdFromToken should fail for: $invalidToken")
+            assertTrue(permissionsResult.isFailure, "getPermissionsFromToken should fail for: $invalidToken")
+
+            // All should have non-null exceptions
+            assertNotNull(validateResult.exceptionOrNull(), "validateToken should have exception for: $invalidToken")
+            assertNotNull(userIdResult.exceptionOrNull(), "getUserIdFromToken should have exception for: $invalidToken")
+            assertNotNull(permissionsResult.exceptionOrNull(), "getPermissionsFromToken should have exception for: $invalidToken")
+        }
+    }
+
+    // ========== Special Edge Cases for Result API ==========
+
+    @Test
+    fun `Result API should handle expired tokens consistently`() {
+        // Arrange
+        val expiredService = JwtService(testSecret, testIssuer, testAudience, expiration = (-10).seconds)
+        val expiredToken = expiredService.generateToken("user-123", "test", listOf(BerechtigungE.PERSON_READ))
+
+        // Act
+        val validateResult = jwtService.validateToken(expiredToken)
+        val userIdResult = jwtService.getUserIdFromToken(expiredToken)
+        val permissionsResult = jwtService.getPermissionsFromToken(expiredToken)
+
+        // Assert - All should consistently fail for expired tokens
+        assertTrue(validateResult.isFailure)
+        assertTrue(userIdResult.isFailure)
+        assertTrue(permissionsResult.isFailure)
+
+        // All should have JWT verification exceptions
+        assertInstanceOf(JWTVerificationException::class.java, validateResult.exceptionOrNull())
+        assertInstanceOf(JWTVerificationException::class.java, userIdResult.exceptionOrNull())
+        assertInstanceOf(JWTVerificationException::class.java, permissionsResult.exceptionOrNull())
+    }
+
+    @Test
+    fun `Result API should handle wrong issuer and audience consistently`() {
+        // Arrange
+        val wrongConfigService = JwtService(testSecret, "wrong-issuer", "wrong-audience")
+        val wrongToken = wrongConfigService.generateToken("user-123", "test", emptyList())
+
+        // Act
+        val validateResult = jwtService.validateToken(wrongToken)
+        val userIdResult = jwtService.getUserIdFromToken(wrongToken)
+        val permissionsResult = jwtService.getPermissionsFromToken(wrongToken)
+
+        // Assert - All should consistently fail
+        assertTrue(validateResult.isFailure)
+        assertTrue(userIdResult.isFailure)
+        assertTrue(permissionsResult.isFailure)
+
+        // All exceptions should be JWT verification exceptions
+        assertInstanceOf(JWTVerificationException::class.java, validateResult.exceptionOrNull())
+        assertInstanceOf(JWTVerificationException::class.java, userIdResult.exceptionOrNull())
+        assertInstanceOf(JWTVerificationException::class.java, permissionsResult.exceptionOrNull())
+    }
+
+    // ========== Result API Interoperability Tests ==========
+
+    @Test
+    fun `Result API should work well with Kotlin standard library`() {
+        // Arrange
+        val validToken = jwtService.generateToken("user-123", "test", listOf(BerechtigungE.PERSON_READ, BerechtigungE.PFERD_CREATE))
+        val invalidToken = "invalid.token"
+
+        // Act & Assert - Test integration with Kotlin stdlib
+
+        // Use with let
+        val letResult = jwtService.validateToken(validToken).getOrNull()?.let { "Token is valid: $it" }
+        assertEquals("Token is valid: true", letResult)
+
+        // Use with also
+        var sideEffectCalled = false
+        jwtService.getUserIdFromToken(validToken).also { result ->
+            if (result.isSuccess) sideEffectCalled = true
+        }
+        assertTrue(sideEffectCalled)
+
+        // Use with takeIf
+        val conditionalResult = jwtService.getPermissionsFromToken(validToken)
+            .getOrNull()
+            ?.takeIf { it.isNotEmpty() }
+        assertNotNull(conditionalResult)
+        assertEquals(2, conditionalResult!!.size)
+
+        // Use with run
+        val runResult = jwtService.validateToken(invalidToken).run {
+            if (isFailure) "Failed as expected" else "Unexpected success"
+        }
+        assertEquals("Failed as expected", runResult)
+    }
+
+    @Test
+    fun `Result API should support functional programming patterns`() {
+        // Arrange
+        val token = jwtService.generateToken("user-123", "test", listOf(BerechtigungE.PERSON_READ))
+
+        // Act & Assert - Functional patterns
+
+        // Map transformations
+        val transformedValidation = jwtService.validateToken(token)
+            .map { if (it) 1 else 0 }
+            .getOrElse { -1 }
+        assertEquals(1, transformedValidation)
+
+        // Filter-like behavior
+        val hasReadPermission = jwtService.getPermissionsFromToken(token)
+            .map { permissions -> permissions.contains(BerechtigungE.PERSON_READ) }
+            .getOrElse { false }
+        assertTrue(hasReadPermission)
+
+        // Combine multiple Results
+        val combinedCheck = jwtService.validateToken(token).isSuccess &&
+                jwtService.getUserIdFromToken(token).isSuccess &&
+                jwtService.getPermissionsFromToken(token).isSuccess
+        assertTrue(combinedCheck)
+    }
+}
@@ -0,0 +1,345 @@
+package at.mocode.infrastructure.auth.client
+
+import at.mocode.infrastructure.auth.client.model.BerechtigungE
+import com.auth0.jwt.exceptions.JWTVerificationException
+import org.junit.jupiter.api.Assertions.*
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.assertTimeoutPreemptively
+import java.time.Duration
+import kotlin.time.Duration.Companion.minutes
+
+/**
+ * Security-focused tests for JWT handling.
+ * Tests against common JWT vulnerabilities and security attack vectors.
+ */
+class SecurityTest {
+
+    private lateinit var jwtService: JwtService
+    private val testSecret = "a-very-long-and-secure-test-secret-that-is-at-least-512-bits-long-for-hmac512"
+    private val testIssuer = "test-issuer"
+    private val testAudience = "test-audience"
+
+    @BeforeEach
+    fun setUp() {
+        jwtService = JwtService(
+            secret = testSecret,
+            issuer = testIssuer,
+            audience = testAudience,
+            expiration = 60.minutes
+        )
+    }
+
+    // ========== Signature Tampering Tests ==========
+
+    @Test
+    fun `should reject tokens with tampered signatures`() {
+        // Arrange
+        val validToken = jwtService.generateToken("user-123", "testuser", listOf(BerechtigungE.PERSON_READ))
+        val tokenParts = validToken.split(".")
+
+        // Tamper with the signature by changing the last character
+        val tamperedSignature = tokenParts[2].dropLast(1) + "X"
+        val tamperedToken = "${tokenParts[0]}.${tokenParts[1]}.$tamperedSignature"
+
+        // Act
+        val result = jwtService.validateToken(tamperedToken)
+
+        // Assert
+        assertTrue(result.isFailure)
+        assertInstanceOf(JWTVerificationException::class.java, result.exceptionOrNull())
+    }
+
+    @Test
+    fun `should reject tokens with completely different signatures`() {
+        // Arrange
+        val validToken = jwtService.generateToken("user-123", "testuser", emptyList())
+        val anotherValidToken = jwtService.generateToken("user-456", "anotheruser", emptyList())
+
+        val tokenParts1 = validToken.split(".")
+        val tokenParts2 = anotherValidToken.split(".")
+
+        // Mix signature from different token
+        val mixedToken = "${tokenParts1[0]}.${tokenParts1[1]}.${tokenParts2[2]}"
+
+        // Act
+        val result = jwtService.validateToken(mixedToken)
+
+        // Assert
+        assertTrue(result.isFailure)
+        assertInstanceOf(JWTVerificationException::class.java, result.exceptionOrNull())
+    }
+
+    @Test
+    fun `should reject tokens with extended expiration time`() {
+        // This test simulates an attacker trying to extend the token's validity
+        // by manipulating the payload (even though it will break the signature)
+
+        // Arrange
+        val validToken = jwtService.generateToken("user-123", "testuser", emptyList())
+        val tokenParts = validToken.split(".")
+
+        // Try to use a different payload with extended expiration
+        // (This will fail signature validation, which is the expected behavior)
+        val anotherService = JwtService(testSecret, testIssuer, testAudience, expiration = 24.minutes)
+        val longValidToken = anotherService.generateToken("user-123", "testuser", emptyList())
+        val longValidParts = longValidToken.split(".")
+
+        val tamperedToken = "${longValidParts[0]}.${longValidParts[1]}.${tokenParts[2]}"
+
+        // Act
+        val result = jwtService.validateToken(tamperedToken)
+
+        // Assert
+        assertTrue(result.isFailure)
+    }
+
+    // ========== Timing Attack Resistance Tests ==========
+
+    @Test
+    fun `token validation should be resistant to timing attacks`() {
+        // Arrange
+        val validToken = jwtService.generateToken("user-123", "testuser", emptyList())
+        val invalidTokens = listOf(
+            "invalid.token.signature",
+            validToken.dropLast(5) + "wrong",
+            "completely.wrong.token",
+            ""
+        )
+
+        // Measure validation times for valid and invalid tokens
+        val validationTimes = mutableListOf<Long>()
+
+        // Act - Test multiple times to get consistent timing measurements
+        repeat(10) {
+            // Valid token
+            val start1 = System.nanoTime()
+            jwtService.validateToken(validToken)
+            val end1 = System.nanoTime()
+            validationTimes.add(end1 - start1)
+
+            // Invalid tokens
+            invalidTokens.forEach { invalidToken ->
+                val start2 = System.nanoTime()
+                jwtService.validateToken(invalidToken)
+                val end2 = System.nanoTime()
+                validationTimes.add(end2 - start2)
+            }
+        }
+
+        // Assert - All validation operations should complete reasonably quickly
+        // (This is not a perfect timing attack test but ensures no obvious timing differences)
+        validationTimes.forEach { time ->
+            assertTrue(time < 10_000_000, "Token validation should complete within 10ms (was ${time}ns)")
+        }
+    }
+
+    @Test
+    fun `validation should complete under consistent time limits`() {
+        // Arrange
+        val tokens = (1..20).map {
+            jwtService.generateToken("user-$it", "testuser$it", listOf(BerechtigungE.PERSON_READ))
+        }
+
+        // Act & Assert - Each validation should complete within reasonable time
+        tokens.forEach { token ->
+            assertTimeoutPreemptively(Duration.ofMillis(100)) {
+                val result = jwtService.validateToken(token)
+                assertTrue(result.isSuccess)
+            }
+        }
+    }
+
+    // ========== JWT Vulnerability Tests (Based on Common CVEs) ==========
+
+    @Test
+    fun `should validate against algorithm confusion attack`() {
+        // This test ensures our service doesn't accept tokens with different algorithms
+        // Common attack: changing algorithm from RS256 to HS256 in the header
+
+        // Arrange
+        val validToken = jwtService.generateToken("user-123", "testuser", emptyList())
+        val tokenParts = validToken.split(".")
+
+        // Try to create a token with a manipulated header (algorithm confusion)
+        // In practice, this would require crafting a specific header, but our implementation
+        // should reject any token that doesn't match our configured algorithm
+        val manipulatedHeader = "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9" // RS256 instead of HS512
+        val manipulatedToken = "$manipulatedHeader.${tokenParts[1]}.${tokenParts[2]}"
+
+        // Act
+        val result = jwtService.validateToken(manipulatedToken)
+
+        // Assert
+        assertTrue(result.isFailure)
+    }
+
+    @Test
+    fun `should reject tokens without proper structure`() {
+        // Test malformed tokens that don't follow the JWT structure
+        val malformedTokens = listOf(
+            "not.a.jwt",
+            "only.two.parts",
+            "too.many.parts.here.extra",
+            ".empty.first.",
+            "first..third",
+            "first.second.",
+            "",
+            "single-string-no-dots"
+        )
+
+        malformedTokens.forEach { malformedToken ->
+            val result = jwtService.validateToken(malformedToken)
+            assertTrue(result.isFailure, "Malformed token '$malformedToken' should be rejected")
+        }
+    }
+
+    @Test
+    fun `should handle extremely long tokens without hanging`() {
+        // Test against DoS attacks using extremely long tokens
+        val longString = "a".repeat(10000)
+        val longTokens = listOf(
+            "$longString.valid.token",
+            "valid.$longString.token",
+            "valid.token.$longString",
+            "$longString.$longString.$longString"
+        )
+
+        longTokens.forEach { longToken ->
+            assertTimeoutPreemptively(Duration.ofSeconds(1)) {
+                val result = jwtService.validateToken(longToken)
+                assertTrue(result.isFailure, "Long token should be rejected quickly")
+            }
+        }
+    }
+
+    // ========== Token Replay Attack Tests ==========
+
+    @Test
+    fun `should handle multiple validations of same token consistently`() {
+        // Test that the same token always produces the same validation result
+        // This ensures no state is maintained that could be exploited
+
+        val token = jwtService.generateToken("user-123", "testuser", listOf(BerechtigungE.PERSON_READ))
+
+        repeat(10) {
+            val result = jwtService.validateToken(token)
+            assertTrue(result.isSuccess, "Same token should always validate successfully")
+
+            val userId = jwtService.getUserIdFromToken(token)
+            assertEquals("user-123", userId.getOrNull())
+
+            val permissions = jwtService.getPermissionsFromToken(token)
+            assertEquals(1, permissions.getOrElse { emptyList() }.size)
+        }
+    }
+
+    // ========== Input Validation Security Tests ==========
+
+    @Test
+    fun `should handle special characters and injection attempts`() {
+        // Test with various special characters that might cause issues
+        val specialUserIds = listOf(
+            "user'; DROP TABLE users; --",
+            "user<script>alert('xss')</script>",
+            "user\n\r\t",
+            "user\u0000null",
+            "user${'\u0001'}control",
+            "../../../etc/passwd"
+        )
+
+        specialUserIds.forEach { specialUserId ->
+            val token = jwtService.generateToken(specialUserId, "testuser", emptyList())
+            val result = jwtService.getUserIdFromToken(token)
+
+            assertTrue(result.isSuccess)
+            assertEquals(specialUserId, result.getOrNull(),
+                "Special characters in user ID should be preserved exactly")
+        }
+    }
+
+    @Test
+    fun `should handle unicode and international characters`() {
+        // Test with international characters to ensure proper encoding/decoding
+        val internationalUserIds = listOf(
+            "用户123", // Chinese
+            "utilisateur123", // French
+            "пользователь123", // Russian
+            "مستخدم123", // Arabic
+            "🧑‍💻user123" // Emoji
+        )
+
+        internationalUserIds.forEach { userId ->
+            val token = jwtService.generateToken(userId, "testuser", emptyList())
+            val result = jwtService.getUserIdFromToken(token)
+
+            assertTrue(result.isSuccess)
+            assertEquals(userId, result.getOrNull(),
+                "International characters should be handled correctly")
+        }
+    }
+
+    // ========== Rate Limiting Simulation Tests ==========
+
+    @Test
+    fun `should handle high frequency validation requests`() {
+        // Simulate high-frequency validation to ensure no memory leaks or performance degradation
+        val token = jwtService.generateToken("user-123", "testuser", emptyList())
+
+        val startTime = System.currentTimeMillis()
+        repeat(1000) {
+            val result = jwtService.validateToken(token)
+            assertTrue(result.isSuccess)
+        }
+        val endTime = System.currentTimeMillis()
+
+        // Should complete 1000 validations in a reasonable time (less than 5 seconds)
+        assertTrue(endTime - startTime < 5000,
+            "1000 token validations should complete within 5 seconds")
+    }
+
+    // ========== Memory Safety Tests ==========
+
+    @Test
+    fun `should not leak sensitive information in error messages`() {
+        // Ensure that error messages don't contain sensitive information
+        val invalidToken = "invalid.token.here"
+        val result = jwtService.validateToken(invalidToken)
+
+        assertTrue(result.isFailure)
+        val exception = result.exceptionOrNull()
+        assertNotNull(exception)
+
+        // Error message should not contain the secret or other sensitive information
+        val errorMessage = exception!!.message ?: ""
+        assertFalse(errorMessage.contains(testSecret),
+            "Error message should not contain the secret")
+        assertFalse(errorMessage.contains("HMAC"),
+            "Error message should not reveal internal algorithm details")
+    }
+
+    @Test
+    fun `should handle concurrent validation requests safely`() {
+        // Test thread safety of JWT validation
+        val token = jwtService.generateToken("user-123", "testuser", emptyList())
+        val results = mutableListOf<Boolean>()
+
+        val threads = (1..10).map { threadIndex ->
+            Thread {
+                repeat(100) {
+                    val result = jwtService.validateToken(token)
+                    synchronized(results) {
+                        results.add(result.isSuccess)
+                    }
+                }
+            }
+        }
+
+        threads.forEach { it.start() }
+        threads.forEach { it.join() }
+
+        // All validations should succeed
+        assertEquals(1000, results.size)
+        assertTrue(results.all { it }, "All concurrent validations should succeed")
+    }
+}