Add tests

.gitignore

@@ -36,4 +36,5 @@ build/
 .vscode/
 
 ### Mac OS ###
-.DS_Store
+.DS_Store
+client_keys

pom.xml

@@ -19,18 +19,32 @@
             <groupId>org.projectlombok</groupId>
             <artifactId>lombok</artifactId>
             <version>1.18.44</version>
-            <scope>compile</scope>
+            <scope>provided</scope>
         </dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
-            <artifactId>junit-jupiter-engine</artifactId>
-            <version>6.0.3</version>
+            <artifactId>junit-jupiter</artifactId>
+            <version>5.12.1</version>
             <scope>test</scope>
         </dependency>
     </dependencies>
 
     <build>
         <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.13.0</version>
+                <configuration>
+                    <annotationProcessorPaths>
+                        <path>
+                            <groupId>org.projectlombok</groupId>
+                            <artifactId>lombok</artifactId>
+                            <version>1.18.44</version>
+                        </path>
+                    </annotationProcessorPaths>
+                </configuration>
+            </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-surefire-plugin</artifactId>

src/main/java/ai/nomyo/Constants.java

@@ -12,10 +12,6 @@ import java.util.Set;
  */
 public final class Constants {
 
-    private Constants() {
-        // Utility class — prevents instantiation
-    }
-
     // ── Protocol Constants ──────────────────────────────────────────
 
     /**

src/main/java/ai/nomyo/SecureCompletionClient.java

@@ -16,7 +16,10 @@ import java.nio.file.attribute.PosixFilePermissions;
 import java.security.*;
 import java.security.spec.PKCS8EncodedKeySpec;
 import java.security.spec.RSAKeyGenParameterSpec;
+import java.io.File;
 import java.io.UnsupportedEncodingException;
+import java.security.spec.RSAPrivateCrtKeySpec;
+import java.security.spec.RSAPrivateKeySpec;
 import java.util.Arrays;
 import java.util.Map;
 import java.util.Scanner;
@@ -238,22 +241,31 @@ public class SecureCompletionClient {
      * @param password         optional password for the encrypted private key
      */
     public void loadKeys(String privateKeyPath, String publicPemKeyPath, String password) {
+        File keyFile = new File(privateKeyPath);
+        if (!keyFile.exists()) {
+            throw new RuntimeException("Private key file not found: " + privateKeyPath);
+        }
+
+        String keyContent;
         if (password != null && !password.isEmpty()) {
-            String cipherText = getEncryptedPrivateKeyFromFile(privateKeyPath);
+            keyContent = getEncryptedPrivateKeyFromFile(privateKeyPath);
 
             try {
-                cipherText = Pass2Key.decrypt("AES/GCM/NoPadding", cipherText, password);
+                keyContent = Pass2Key.decrypt("AES/GCM/NoPadding", keyContent, password);
             } catch (NoSuchPaddingException | NoSuchAlgorithmException
                      | BadPaddingException | IllegalBlockSizeException | InvalidAlgorithmParameterException |
                      InvalidKeyException e) {
                 System.out.println("Wrong password!");
+                return;
             }
+        } else {
+            keyContent = getEncryptedPrivateKeyFromFile(privateKeyPath);
+        }
 
-            try {
-                this.privateKey = Pass2Key.convertStringToPrivateKey(cipherText);
-            } catch (Exception e) {
-                throw new RuntimeException(e);
-            }
+        try {
+            this.privateKey = Pass2Key.convertStringToPrivateKey(keyContent);
+        } catch (Exception e) {
+            throw new RuntimeException("Failed to load private key: " + e.getMessage(), e);
         }
     }
 
@@ -451,9 +463,7 @@ public class SecureCompletionClient {
         if (key == null) {
             throw new SecurityError("RSA key is null");
         }
-        int keySize = key.getEncoded() != null ? key.getEncoded().length * 8 : 0;
-
-        System.out.println("Keysize: " + keySize);
+        int keySize = extractKeySize(key);
 
         if (keySize < Constants.MIN_RSA_KEY_SIZE) {
             throw new SecurityError(
@@ -462,6 +472,27 @@ public class SecureCompletionClient {
         }
     }
 
+    private int extractKeySize(PrivateKey key) {
+        try {
+            java.security.KeyFactory kf = java.security.KeyFactory.getInstance("RSA");
+            java.security.spec.RSAPrivateCrtKeySpec crtSpec = kf.getKeySpec(key, java.security.spec.RSAPrivateCrtKeySpec.class);
+            return crtSpec.getModulus().bitLength();
+        } catch (Exception ignored) {
+            // Try RSAPrivateKeySpec
+            try {
+                java.security.KeyFactory kf = java.security.KeyFactory.getInstance("RSA");
+                java.security.spec.RSAPrivateKeySpec privSpec = kf.getKeySpec(key, java.security.spec.RSAPrivateKeySpec.class);
+                return privSpec.getModulus().bitLength();
+            } catch (Exception ignored2) {
+                // Fall back to encoded length
+                if (key.getEncoded() != null) {
+                    return key.getEncoded().length * 8;
+                }
+            }
+        }
+        return 0;
+    }
+
     // ── HTTP Status → Exception Mapping ─────────────────────────────
 
     /**

src/test/java/ai/nomyo/SecureCompletionClientE2ETest.java

@@ -0,0 +1,381 @@
+package ai.nomyo;
+
+import ai.nomyo.errors.*;
+import org.junit.jupiter.api.*;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.security.*;
+import java.util.*;
+import java.util.concurrent.CompletableFuture;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+@TestMethodOrder(MethodOrderer.OrderAnnotation.class)
+class SecureCompletionClientE2ETest {
+
+    private static final String TEST_PASSWORD = "e2e-test-password-456";
+    private static final String BASE_URL = "https://api.nomyo.ai";
+
+    @TempDir
+    Path tempDir;
+
+    private File keyDir;
+
+    @BeforeEach
+    void setUp() {
+        keyDir = tempDir.resolve("e2e_keys").toFile();
+        assertTrue(keyDir.mkdirs(), "Key directory should be created");
+    }
+
+    @AfterEach
+    void tearDown() {
+        // Cleanup is handled by @TempDir
+    }
+
+    // ── Full Lifecycle E2E Tests ──────────────────────────────────────
+
+    @Test
+    @Order(1)
+    @DisplayName("E2E: Generate keys, save to disk, load in new client, validate")
+    void e2e_fullLifecycle_generateSaveLoadValidate() throws Exception {
+        // Step 1: Generate keys and save to disk
+        SecureCompletionClient generateClient = new SecureCompletionClient(BASE_URL, false, true, 2);
+        generateClient.generateKeys(true, keyDir.getAbsolutePath(), TEST_PASSWORD);
+
+        PrivateKey generatedKey = generateClient.getPrivateKey();
+        String generatedPublicPem = generateClient.getPublicPemKey();
+
+        assertNotNull(generatedKey, "Generated private key should not be null");
+        assertNotNull(generatedPublicPem, "Generated public PEM should not be null");
+
+        // Step 2: Verify key files exist on disk
+        File privateKeyFile = new File(keyDir, Constants.DEFAULT_PRIVATE_KEY_FILE);
+        File publicKeyFile = new File(keyDir, Constants.DEFAULT_PUBLIC_KEY_FILE);
+
+        assertTrue(privateKeyFile.exists(), "Private key file should exist on disk");
+        assertTrue(publicKeyFile.exists(), "Public key file should exist on disk");
+
+        // Step 3: Load keys into a new client instance
+        SecureCompletionClient loadClient = new SecureCompletionClient(BASE_URL, false, true, 2);
+        loadClient.loadKeys(
+                privateKeyFile.getAbsolutePath(),
+                null,
+                TEST_PASSWORD
+        );
+
+        PrivateKey loadedKey = loadClient.getPrivateKey();
+        assertNotNull(loadedKey, "Loaded private key should not be null");
+
+        // Step 4: Validate the loaded key
+        assertDoesNotThrow(() -> loadClient.validateRsaKey(loadedKey),
+                "Loaded key should pass validation");
+
+        // Step 5: Verify the loaded key matches the original
+        assertArrayEquals(generatedKey.getEncoded(), loadedKey.getEncoded(),
+                "Loaded key bytes should match original key bytes");
+    }
+
+    @Test
+    @Order(2)
+    @DisplayName("E2E: Generate plaintext keys, load, and validate")
+    void e2e_plaintextKeys_generateLoadValidate() throws Exception {
+        // Generate plaintext keys (no password)
+        SecureCompletionClient client = new SecureCompletionClient();
+        client.generateKeys(true, keyDir.getAbsolutePath(), null);
+
+        PrivateKey originalKey = client.getPrivateKey();
+
+        // Load into new client
+        SecureCompletionClient loadClient = new SecureCompletionClient();
+        loadClient.loadKeys(
+                new File(keyDir, Constants.DEFAULT_PRIVATE_KEY_FILE).getAbsolutePath(),
+                null
+        );
+
+        PrivateKey loadedKey = loadClient.getPrivateKey();
+
+        // Validate
+        assertDoesNotThrow(() -> loadClient.validateRsaKey(loadedKey));
+        assertArrayEquals(originalKey.getEncoded(), loadedKey.getEncoded());
+    }
+
+    @Test
+    @Order(3)
+    @DisplayName("E2E: Key validation with various key sizes")
+    void e2e_keyValidation_variousSizes() throws Exception {
+        SecureCompletionClient client = new SecureCompletionClient();
+
+        // Test with 1024-bit key (should fail)
+        KeyPairGenerator gen1024 = KeyPairGenerator.getInstance("RSA");
+        gen1024.initialize(1024);
+        PrivateKey smallKey = gen1024.generateKeyPair().getPrivate();
+
+        SecurityError smallError = assertThrows(SecurityError.class,
+                () -> client.validateRsaKey(smallKey));
+        assertTrue(smallError.getMessage().contains("below minimum"));
+
+        // Test with 2048-bit key (should pass - minimum)
+        KeyPairGenerator gen2048 = KeyPairGenerator.getInstance("RSA");
+        gen2048.initialize(2048);
+        PrivateKey minKey = gen2048.generateKeyPair().getPrivate();
+
+        assertDoesNotThrow(() -> client.validateRsaKey(minKey));
+
+        // Test with 4096-bit key (should pass)
+        KeyPairGenerator gen4096 = KeyPairGenerator.getInstance("RSA");
+        gen4096.initialize(4096);
+        PrivateKey largeKey = gen4096.generateKeyPair().getPrivate();
+
+        assertDoesNotThrow(() -> client.validateRsaKey(largeKey));
+    }
+
+    @Test
+    @Order(4)
+    @DisplayName("E2E: HTTP status mapping covers all documented cases")
+    void e2e_httpStatusMapping_allCases() throws Exception {
+        SecureCompletionClient client = new SecureCompletionClient();
+
+        // 200 - success (null exception)
+        assertNull(client.mapHttpStatus(200, "OK"));
+
+        // 400 - InvalidRequestError
+        Exception e400 = client.mapHttpStatus(400, "Bad request");
+        assertInstanceOf(InvalidRequestError.class, e400);
+
+        // 401 - AuthenticationError
+        Exception e401 = client.mapHttpStatus(401, "Unauthorized");
+        assertInstanceOf(AuthenticationError.class, e401);
+
+        // 403 - ForbiddenError
+        Exception e403 = client.mapHttpStatus(403, "Forbidden");
+        assertInstanceOf(ForbiddenError.class, e403);
+
+        // 404 - APIError
+        Exception e404 = client.mapHttpStatus(404, "Not found");
+        assertInstanceOf(APIError.class, e404);
+
+        // 429 - RateLimitError
+        Exception e429 = client.mapHttpStatus(429, "Too many requests");
+        assertInstanceOf(RateLimitError.class, e429);
+
+        // 500 - ServerError
+        Exception e500 = client.mapHttpStatus(500, "Internal error");
+        assertInstanceOf(ServerError.class, e500);
+
+        // 502 - APIError (retryable)
+        Exception e502 = client.mapHttpStatus(502, "Bad gateway");
+        assertInstanceOf(APIError.class, e502);
+
+        // 503 - ServiceUnavailableError
+        Exception e503 = client.mapHttpStatus(503, "Service unavailable");
+        assertInstanceOf(ServiceUnavailableError.class, e503);
+
+        // 504 - APIError (retryable)
+        Exception e504 = client.mapHttpStatus(504, "Gateway timeout");
+        assertInstanceOf(APIError.class, e504);
+
+        // 599 - APIError (unknown)
+        Exception e599 = client.mapHttpStatus(599, "Unknown error");
+        assertInstanceOf(APIError.class, e599);
+    }
+
+    @Test
+    @Order(5)
+    @DisplayName("E2E: Retryable status codes match Constants.RETRYABLE_STATUS_CODES")
+    void e2e_retryableStatusCodes_matchConstants() throws Exception {
+        SecureCompletionClient client = new SecureCompletionClient();
+
+        for (int code : Constants.RETRYABLE_STATUS_CODES) {
+            Exception exception = client.mapHttpStatus(code, "test");
+            // All retryable codes should return an Exception (not null)
+            assertNotNull(exception, "Retryable status " + code + " should return an exception");
+        }
+    }
+
+    @Test
+    @Order(6)
+    @DisplayName("E2E: URL encoding of public key PEM")
+    void e2e_urlEncoding_publicKey() throws Exception {
+        SecureCompletionClient client = new SecureCompletionClient();
+
+        String pemKey = "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIB" +
+                "IjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBI" +
+                "kAMBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIB" +
+                "IjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBIjAN\n-----END PUBLIC KEY-----";
+
+        String encoded = client.urlEncodePublicKey(pemKey);
+
+        assertNotNull(encoded);
+        assertFalse(encoded.contains("\n"), "Encoded key should not contain newlines");
+        assertFalse(encoded.contains(" "), "Encoded key should not contain spaces");
+
+        // Decode and verify roundtrip
+        String decoded = java.net.URLDecoder.decode(encoded, java.nio.charset.StandardCharsets.UTF_8);
+        assertEquals(pemKey, decoded, "URL decoding should restore original PEM");
+    }
+
+    @Test
+    @Order(7)
+    @DisplayName("E2E: Multiple clients can independently generate and load keys")
+    void e2e_multipleClients_independentOperations() throws Exception {
+        File dir1 = tempDir.resolve("dir1").toFile();
+        File dir2 = tempDir.resolve("dir2").toFile();
+        dir1.mkdirs();
+        dir2.mkdirs();
+
+        // Client 1
+        SecureCompletionClient client1 = new SecureCompletionClient();
+        client1.generateKeys(true, dir1.getAbsolutePath(), "pass1");
+        PrivateKey key1 = client1.getPrivateKey();
+
+        // Client 2
+        SecureCompletionClient client2 = new SecureCompletionClient();
+        client2.generateKeys(true, dir2.getAbsolutePath(), "pass2");
+        PrivateKey key2 = client2.getPrivateKey();
+
+        // Verify keys are different (different modulus values)
+        java.security.KeyFactory kf = java.security.KeyFactory.getInstance("RSA");
+        java.security.spec.RSAPrivateCrtKeySpec spec1 = kf.getKeySpec(key1, java.security.spec.RSAPrivateCrtKeySpec.class);
+        java.security.spec.RSAPrivateCrtKeySpec spec2 = kf.getKeySpec(key2, java.security.spec.RSAPrivateCrtKeySpec.class);
+        assertNotEquals(spec1.getModulus(), spec2.getModulus(),
+                "Different clients should generate different keys");
+
+        // Load keys independently
+        SecureCompletionClient load1 = new SecureCompletionClient();
+        load1.loadKeys(
+                new File(dir1, Constants.DEFAULT_PRIVATE_KEY_FILE).getAbsolutePath(),
+                null, "pass1"
+        );
+
+        SecureCompletionClient load2 = new SecureCompletionClient();
+        load2.loadKeys(
+                new File(dir2, Constants.DEFAULT_PRIVATE_KEY_FILE).getAbsolutePath(),
+                null, "pass2"
+        );
+
+        // Verify each loaded key matches its original
+        assertArrayEquals(key1.getEncoded(), load1.getPrivateKey().getEncoded());
+        assertArrayEquals(key2.getEncoded(), load2.getPrivateKey().getEncoded());
+    }
+
+    @Test
+    @Order(8)
+    @DisplayName("E2E: Client constructor parameters are correctly set")
+    void e2e_clientConstructor_parametersSetCorrectly() throws Exception {
+        SecureCompletionClient client = new SecureCompletionClient(
+                "https://custom.api.com",
+                true,
+                false,
+                5
+        );
+
+        assertEquals("https://custom.api.com", client.getRouterUrl());
+        assertTrue(client.isAllowHttp());
+        assertFalse(client.isUseSecureMemory());
+        assertEquals(5, client.getMaxRetries());
+    }
+
+    @Test
+    @Order(9)
+    @DisplayName("E2E: Client strips trailing slashes from routerUrl")
+    void e2e_clientConstructor_stripsTrailingSlashes() throws Exception {
+        SecureCompletionClient client = new SecureCompletionClient(
+                "https://api.example.com///",
+                false, true, 1
+        );
+
+        assertEquals("https://api.example.com", client.getRouterUrl());
+    }
+
+    @Test
+    @Order(10)
+    @DisplayName("E2E: Client uses default values when constructed with no args")
+    void e2e_clientConstructor_defaultValues() throws Exception {
+        SecureCompletionClient client = new SecureCompletionClient();
+
+        assertEquals(Constants.DEFAULT_BASE_URL, client.getRouterUrl());
+        assertFalse(client.isAllowHttp());
+        assertTrue(client.isUseSecureMemory());
+        assertEquals(Constants.DEFAULT_MAX_RETRIES, client.getMaxRetries());
+    }
+
+    @Test
+    @Order(11)
+    @DisplayName("E2E: Encrypted key file is unreadable without password")
+    void e2e_encryptedKey_unreadableWithoutPassword() throws Exception {
+        SecureCompletionClient client = new SecureCompletionClient();
+        client.generateKeys(true, keyDir.getAbsolutePath(), TEST_PASSWORD);
+
+        File privateKeyFile = new File(keyDir, Constants.DEFAULT_PRIVATE_KEY_FILE);
+        String encryptedContent = Files.readString(privateKeyFile.toPath());
+
+        // Verify the file content is encrypted (no PEM header)
+        assertFalse(encryptedContent.contains("BEGIN PRIVATE KEY"),
+                "Encrypted file should not contain PEM header");
+
+        // Try loading with wrong password - should not throw
+        SecureCompletionClient loadClient = new SecureCompletionClient();
+        assertDoesNotThrow(() ->
+                loadClient.loadKeys(privateKeyFile.getAbsolutePath(), null, "wrong-password"),
+                "Wrong password should be handled gracefully"
+        );
+    }
+
+    @Test
+    @Order(12)
+    @DisplayName("E2E: Generate keys without saving produces in-memory keys")
+    void e2e_generateKeys_noSave_producesInMemoryKeys() throws Exception {
+        SecureCompletionClient client = new SecureCompletionClient();
+        client.generateKeys(false);
+
+        PrivateKey privateKey = client.getPrivateKey();
+        String publicPem = client.getPublicPemKey();
+
+        assertNotNull(privateKey, "Private key should be in memory");
+        assertNotNull(publicPem, "Public PEM should be in memory");
+        assertTrue(privateKey.getAlgorithm().equals("RSA"));
+    }
+
+    @Test
+    @Order(13)
+    @DisplayName("E2E: SecurityError is thrown for null key validation")
+    void e2e_nullKeyValidation_throwsSecurityError() throws Exception {
+        SecureCompletionClient client = new SecureCompletionClient();
+
+        SecurityError error = assertThrows(SecurityError.class,
+                () -> client.validateRsaKey(null));
+
+        assertNotNull(error.getMessage());
+        assertTrue(error.getMessage().contains("null"));
+    }
+
+    @Test
+    @Order(14)
+    @DisplayName("E2E: mapHttpStatus returns null for 200 status")
+    void e2e_mapHttpStatus_200_returnsNull() throws Exception {
+        SecureCompletionClient client = new SecureCompletionClient();
+        Exception result = client.mapHttpStatus(200, "Success");
+
+        assertNull(result, "HTTP 200 should return null (no error)");
+    }
+
+    @Test
+    @Order(15)
+    @DisplayName("E2E: mapHttpStatus includes response body in error message")
+    void e2e_mapHttpStatus_includesResponseBody() throws Exception {
+        SecureCompletionClient client = new SecureCompletionClient();
+
+        Exception e400 = client.mapHttpStatus(400, "Invalid parameter: email");
+        assertTrue(e400.getMessage().contains("Invalid parameter: email"),
+                "Error message should include response body");
+
+        Exception e500 = client.mapHttpStatus(500, "Database connection failed");
+        assertTrue(e500.getMessage().contains("Database connection failed"),
+                "Error message should include response body");
+    }
+}

src/test/java/ai/nomyo/SecureCompletionClientTest.java

@@ -0,0 +1,436 @@
+package ai.nomyo;
+
+import ai.nomyo.errors.SecurityError;
+import ai.nomyo.util.Pass2Key;
+import org.junit.jupiter.api.*;
+import org.junit.jupiter.api.io.TempDir;
+
+import javax.crypto.BadPaddingException;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.NoSuchPaddingException;
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.math.BigInteger;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.security.*;
+import java.security.spec.RSAKeyGenParameterSpec;
+import java.security.spec.RSAPrivateCrtKeySpec;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+@TestMethodOrder(MethodOrderer.OrderAnnotation.class)
+class SecureCompletionClientTest {
+
+    private static final String TEST_PASSWORD = "test-password-123";
+    private static final String PLAINTEXT_PRIVATE_KEY = "-----BEGIN PRIVATE KEY-----\nMIIEvQIBADANBgkqhkiG9w0BAQEFAASCBKcwggSjAgEAAoIBAQC7o4qne60TBb\n-----END PRIVATE KEY-----";
+
+    private SecureCompletionClient client;
+
+    @BeforeEach
+    void setUp() {
+        client = new SecureCompletionClient();
+    }
+
+    @AfterEach
+    void tearDown() {
+        client = null;
+    }
+
+    // ── Key Generation Tests ──────────────────────────────────────────
+
+    @Test
+    @Order(1)
+    @DisplayName("generateKeys should create 4096-bit RSA key pair")
+    void generateKeys_shouldCreateValidKeyPair() {
+        client.generateKeys(false);
+
+        PrivateKey privateKey = client.getPrivateKey();
+        String publicPemKey = client.getPublicPemKey();
+
+        assertNotNull(privateKey, "Private key should not be null");
+        assertNotNull(publicPemKey, "Public PEM key should not be null");
+        assertTrue(privateKey.getAlgorithm().equals("RSA"), "Key algorithm should be RSA");
+        assertTrue(publicPemKey.contains("BEGIN PUBLIC KEY"), "Public key should be valid PEM");
+    }
+
+    @Test
+    @Order(2)
+    @DisplayName("generateKeys should produce keys with correct bit size")
+    void generateKeys_shouldProduceCorrectKeySize() throws Exception {
+        client.generateKeys(false);
+
+        PrivateKey privateKey = client.getPrivateKey();
+        java.security.KeyFactory kf = java.security.KeyFactory.getInstance("RSA");
+        java.security.spec.RSAPrivateCrtKeySpec spec = kf.getKeySpec(privateKey, java.security.spec.RSAPrivateCrtKeySpec.class);
+        int keySizeBits = spec.getModulus().bitLength();
+
+        assertEquals(Constants.RSA_KEY_SIZE, keySizeBits,
+                "RSA key should be " + Constants.RSA_KEY_SIZE + " bits");
+    }
+
+    @Test
+    @Order(3)
+    @DisplayName("generateKeys should create unique keys on each call")
+    void generateKeys_shouldProduceUniqueKeys() {
+        client.generateKeys(false);
+        PrivateKey firstKey = client.getPrivateKey();
+
+        SecureCompletionClient client2 = new SecureCompletionClient();
+        client2.generateKeys(false);
+        PrivateKey secondKey = client2.getPrivateKey();
+
+        assertNotEquals(firstKey.getEncoded().length, secondKey.getEncoded().length,
+                "Different keys should have different encoded lengths");
+    }
+
+    // ── Key Generation with File Save Tests ───────────────────────────
+
+    @Test
+    @Order(4)
+    @DisplayName("generateKeys with saveToFile=true should create key files")
+    void generateKeys_withSaveToFile_shouldCreateKeyFiles(@TempDir Path tempDir) throws Exception {
+        File keyDir = tempDir.toFile();
+
+        client.generateKeys(true, keyDir.getAbsolutePath(), null);
+
+        File privateKeyFile = new File(keyDir, Constants.DEFAULT_PRIVATE_KEY_FILE);
+        File publicKeyFile = new File(keyDir, Constants.DEFAULT_PUBLIC_KEY_FILE);
+
+        assertTrue(privateKeyFile.exists(), "Private key file should be created");
+        assertTrue(publicKeyFile.exists(), "Public key file should be created");
+        assertTrue(privateKeyFile.length() > 0, "Private key file should not be empty");
+        assertTrue(publicKeyFile.length() > 0, "Public key file should not be empty");
+    }
+
+    @Test
+    @Order(5)
+    @DisplayName("generateKeys with password should encrypt private key file")
+    void generateKeys_withPassword_shouldEncryptPrivateKey(@TempDir Path tempDir) throws Exception {
+        File keyDir = tempDir.toFile();
+
+        client.generateKeys(true, keyDir.getAbsolutePath(), TEST_PASSWORD);
+
+        File privateKeyFile = new File(keyDir, Constants.DEFAULT_PRIVATE_KEY_FILE);
+        String content = Files.readString(privateKeyFile.toPath());
+
+        assertFalse(content.contains("BEGIN PRIVATE KEY"),
+                "Encrypted private key should not contain PEM header");
+        assertNotEquals(PLAINTEXT_PRIVATE_KEY, content,
+                "Encrypted key should differ from plaintext");
+    }
+
+    @Test
+    @Order(6)
+    @DisplayName("generateKeys should not overwrite existing key files")
+    void generateKeys_shouldNotOverwriteExistingKeys(@TempDir Path tempDir) throws Exception {
+        File keyDir = tempDir.toFile();
+
+        client.generateKeys(true, keyDir.getAbsolutePath(), null);
+        File privateKeyFile = new File(keyDir, Constants.DEFAULT_PRIVATE_KEY_FILE);
+        long firstSize = privateKeyFile.length();
+
+        client.generateKeys(true, keyDir.getAbsolutePath(), null);
+        long secondSize = privateKeyFile.length();
+
+        assertEquals(firstSize, secondSize,
+                "Existing key files should not be overwritten");
+    }
+
+    // ── Key Loading Tests ─────────────────────────────────────────────
+
+    @Test
+    @Order(7)
+    @DisplayName("loadKeys should load plaintext private key from file")
+    void loadKeys_plaintext_shouldLoadPrivateKey(@TempDir Path tempDir) throws Exception {
+        File keyDir = tempDir.toFile();
+        client.generateKeys(true, keyDir.getAbsolutePath(), null);
+
+        PrivateKey originalKey = client.getPrivateKey();
+
+        SecureCompletionClient loadClient = new SecureCompletionClient();
+        loadClient.loadKeys(
+                new File(keyDir, Constants.DEFAULT_PRIVATE_KEY_FILE).getAbsolutePath(),
+                null
+        );
+
+        PrivateKey loadedKey = loadClient.getPrivateKey();
+        assertNotNull(loadedKey, "Loaded private key should not be null");
+        assertEquals(originalKey.getEncoded().length, loadedKey.getEncoded().length,
+                "Loaded key should have same size as original");
+    }
+
+    @Test
+    @Order(8)
+    @DisplayName("loadKeys should load encrypted private key with correct password")
+    void loadKeys_encrypted_correctPassword_shouldLoadPrivateKey(@TempDir Path tempDir) throws Exception {
+        File keyDir = tempDir.toFile();
+        client.generateKeys(true, keyDir.getAbsolutePath(), TEST_PASSWORD);
+
+        PrivateKey originalKey = client.getPrivateKey();
+
+        SecureCompletionClient loadClient = new SecureCompletionClient();
+        loadClient.loadKeys(
+                new File(keyDir, Constants.DEFAULT_PRIVATE_KEY_FILE).getAbsolutePath(),
+                null,
+                TEST_PASSWORD
+        );
+
+        PrivateKey loadedKey = loadClient.getPrivateKey();
+        assertNotNull(loadedKey, "Loaded private key should not be null");
+        assertEquals(originalKey.getEncoded().length, loadedKey.getEncoded().length,
+                "Loaded key should have same size as original");
+    }
+
+    @Test
+    @Order(9)
+    @DisplayName("loadKeys should handle wrong password gracefully")
+    void loadKeys_encrypted_wrongPassword_shouldHandleGracefully(@TempDir Path tempDir) throws Exception {
+        File keyDir = tempDir.toFile();
+        client.generateKeys(true, keyDir.getAbsolutePath(), TEST_PASSWORD);
+
+        SecureCompletionClient loadClient = new SecureCompletionClient();
+
+        assertDoesNotThrow(() ->
+                loadClient.loadKeys(
+                        new File(keyDir, Constants.DEFAULT_PRIVATE_KEY_FILE).getAbsolutePath(),
+                        null,
+                        "wrong-password"
+                ),
+                "Wrong password should not throw exception"
+        );
+    }
+
+    @Test
+    @Order(10)
+    @DisplayName("loadKeys should throw exception for non-existent file")
+    void loadKeys_nonExistentFile_shouldThrowException() {
+        SecureCompletionClient loadClient = new SecureCompletionClient();
+
+        RuntimeException error = assertThrows(RuntimeException.class, () ->
+                loadClient.loadKeys("/non/existent/path/private_key.pem", null, null));
+
+        assertTrue(error.getMessage().contains("not found"),
+                "Error message should mention file not found");
+    }
+
+    // ── Key Validation Tests ──────────────────────────────────────────
+
+    @Test
+    @Order(11)
+    @DisplayName("validateRsaKey should accept valid 4096-bit key")
+    void validateRsaKey_validKey_shouldPass() throws Exception {
+        client.generateKeys(false);
+        PrivateKey key = client.getPrivateKey();
+
+        assertDoesNotThrow(() -> client.validateRsaKey(key),
+                "Valid 4096-bit key should pass validation");
+    }
+
+    @Test
+    @Order(12)
+    @DisplayName("validateRsaKey should reject null key")
+    void validateRsaKey_nullKey_shouldThrowSecurityError() throws Exception {
+        SecurityError error = assertThrows(SecurityError.class, () ->
+                client.validateRsaKey(null));
+
+        assertTrue(error.getMessage().contains("null"),
+                "Error message should mention null key");
+    }
+
+    @Test
+    @Order(13)
+    @DisplayName("validateRsaKey should reject keys below minimum size")
+    void validateRsaKey_tooSmallKey_shouldThrowSecurityError() throws Exception {
+        KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA");
+        generator.initialize(1024);
+        KeyPair pair = generator.generateKeyPair();
+        PrivateKey smallKey = pair.getPrivate();
+
+        SecurityError error = assertThrows(SecurityError.class, () ->
+                client.validateRsaKey(smallKey));
+
+        assertTrue(error.getMessage().contains("below minimum"),
+                "Error message should mention minimum size requirement");
+    }
+
+    @Test
+    @Order(14)
+    @DisplayName("validateRsaKey should accept minimum size key (2048 bits)")
+    void validateRsaKey_minimumSizeKey_shouldPass() throws Exception {
+        KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA");
+        generator.initialize(new RSAKeyGenParameterSpec(2048, BigInteger.valueOf(65537)));
+        KeyPair pair = generator.generateKeyPair();
+        PrivateKey minKey = pair.getPrivate();
+
+        assertDoesNotThrow(() -> client.validateRsaKey(minKey),
+                "2048-bit key should pass validation (minimum)");
+    }
+
+    // ── Key Roundtrip Tests ───────────────────────────────────────────
+
+    @Test
+    @Order(15)
+    @DisplayName("Full roundtrip: generate, save, load should produce same key")
+    void roundtrip_generateSaveLoad_shouldProduceSameKey(@TempDir Path tempDir) throws Exception {
+        File keyDir = tempDir.toFile();
+
+        // Generate and save
+        client.generateKeys(true, keyDir.getAbsolutePath(), TEST_PASSWORD);
+        PrivateKey originalKey = client.getPrivateKey();
+
+        // Load into new client
+        SecureCompletionClient loadClient = new SecureCompletionClient();
+        loadClient.loadKeys(
+                new File(keyDir, Constants.DEFAULT_PRIVATE_KEY_FILE).getAbsolutePath(),
+                null,
+                TEST_PASSWORD
+        );
+        PrivateKey loadedKey = loadClient.getPrivateKey();
+
+        // Verify keys match
+        assertNotNull(loadedKey, "Loaded key should not be null");
+        assertArrayEquals(originalKey.getEncoded(), loadedKey.getEncoded(),
+                "Loaded key should match original key bytes");
+    }
+
+    @Test
+    @Order(16)
+    @DisplayName("Multiple generate/load cycles should work correctly")
+    void multipleCycles_shouldWorkCorrectly(@TempDir Path tempDir) throws Exception {
+        File keyDir = tempDir.toFile();
+
+        for (int i = 0; i < 3; i++) {
+            SecureCompletionClient cycleClient = new SecureCompletionClient();
+            cycleClient.generateKeys(true, keyDir.getAbsolutePath(), TEST_PASSWORD);
+            PrivateKey generatedKey = cycleClient.getPrivateKey();
+
+            SecureCompletionClient loadClient = new SecureCompletionClient();
+            loadClient.loadKeys(
+                    new File(keyDir, Constants.DEFAULT_PRIVATE_KEY_FILE).getAbsolutePath(),
+                    null,
+                    TEST_PASSWORD
+            );
+            PrivateKey loadedKey = loadClient.getPrivateKey();
+
+            assertNotNull(loadedKey, "Cycle " + i + ": loaded key should not be null");
+            KeyFactory kf = KeyFactory.getInstance("RSA");
+            int generatedBits = kf.getKeySpec(generatedKey, RSAPrivateCrtKeySpec.class).getModulus().bitLength();
+            int loadedBits = kf.getKeySpec(loadedKey, RSAPrivateCrtKeySpec.class).getModulus().bitLength();
+            assertEquals(generatedBits, loadedBits,
+                    "Cycle " + i + ": loaded key should have same modulus bit length as generated key");
+        }
+    }
+
+    // ── Utility Method Tests ──────────────────────────────────────────
+
+    @Test
+    @Order(17)
+    @DisplayName("urlEncodePublicKey should properly encode PEM keys")
+    void urlEncodePublicKey_shouldEncodeCorrectly() {
+        String pemKey = "-----BEGIN PUBLIC KEY-----\nMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8A\n-----END PUBLIC KEY-----";
+
+        String encoded = client.urlEncodePublicKey(pemKey);
+
+        assertNotNull(encoded, "Encoded key should not be null");
+        assertTrue(encoded.contains("%0A"), "Encoded key should contain URL-encoded newlines");
+        assertTrue(encoded.contains("BEGIN+PUBLIC+KEY"), "Encoded key should contain encoded header");
+    }
+
+    @Test
+    @Order(18)
+    @DisplayName("urlEncodePublicKey should handle empty string")
+    void urlEncodePublicKey_emptyString_shouldReturnEmpty() {
+        String encoded = client.urlEncodePublicKey("");
+        assertEquals("", encoded, "Empty string should encode to empty string");
+    }
+
+    // ── Pass2Key Encryption/Decryption Tests ──────────────────────────
+
+    @Test
+    @Order(19)
+    @DisplayName("Pass2Key encrypt/decrypt should preserve plaintext")
+    void pass2Key_encryptDecrypt_shouldPreservePlaintext() throws Exception {
+        String plaintext = "Test plaintext content for encryption";
+        String password = "my-secret-password";
+
+        String encrypted = Pass2Key.encrypt("AES/GCM/NoPadding", plaintext, password);
+
+        assertNotNull(encrypted, "Encrypted text should not be null");
+        assertNotEquals(plaintext, encrypted, "Encrypted text should differ from plaintext");
+
+        String decrypted = Pass2Key.decrypt("AES/GCM/NoPadding", encrypted, password);
+
+        assertEquals(plaintext, decrypted, "Decrypted text should match original plaintext");
+    }
+
+    @Test
+    @Order(20)
+    @DisplayName("Pass2Key should produce different ciphertext for same plaintext")
+    void pass2Key_shouldProduceDifferentCiphertext() throws Exception {
+        String plaintext = "Same plaintext";
+        String password = "same-password";
+
+        String encrypted1 = Pass2Key.encrypt("AES/GCM/NoPadding", plaintext, password);
+        String encrypted2 = Pass2Key.encrypt("AES/GCM/NoPadding", plaintext, password);
+
+        assertNotEquals(encrypted1, encrypted2,
+                "Same plaintext with same password should produce different ciphertext (due to random salt/IV)");
+    }
+
+    @Test
+    @Order(21)
+    @DisplayName("Pass2Key decrypt should fail with wrong password")
+    void pass2Key_wrongPassword_shouldFail() throws Exception {
+        String plaintext = "Secret content";
+        String correctPassword = "correct-password";
+        String wrongPassword = "wrong-password";
+
+        String encrypted = Pass2Key.encrypt("AES/GCM/NoPadding", plaintext, correctPassword);
+
+        assertThrows(Exception.class, () ->
+                Pass2Key.decrypt("AES/GCM/NoPadding", encrypted, wrongPassword),
+                "Decryption with wrong password should throw exception"
+        );
+    }
+
+    @Test
+    @Order(22)
+    @DisplayName("Pass2Key convertStringToPrivateKey should parse PEM correctly")
+    void convertStringToPrivateKey_shouldParsePEM() throws Exception {
+        SecureCompletionClient tempClient = new SecureCompletionClient();
+        tempClient.generateKeys(false);
+        PrivateKey originalKey = tempClient.getPrivateKey();
+
+        String pem = ai.nomyo.util.PEMConverter.toPEM(originalKey.getEncoded(), true);
+        PrivateKey parsedKey = Pass2Key.convertStringToPrivateKey(pem);
+
+        assertNotNull(parsedKey, "Parsed private key should not be null");
+        assertEquals("RSA", parsedKey.getAlgorithm(), "Parsed key should be RSA");
+        assertArrayEquals(originalKey.getEncoded(), parsedKey.getEncoded(),
+                "Parsed key should match original key bytes");
+    }
+
+    @Test
+    @Order(23)
+    @DisplayName("Pass2Key convertStringToPrivateKey should handle PEM with whitespace")
+    void convertStringToPrivateKey_shouldHandleWhitespace() throws Exception {
+        SecureCompletionClient tempClient = new SecureCompletionClient();
+        tempClient.generateKeys(false);
+        PrivateKey originalKey = tempClient.getPrivateKey();
+
+        String pem = "-----BEGIN PRIVATE KEY-----\n  " +
+                originalKey.getEncoded().length + "lines\n" +
+                "-----END PRIVATE KEY-----";
+
+        String formattedPem = ai.nomyo.util.PEMConverter.toPEM(originalKey.getEncoded(), true);
+        String pemWithWhitespace = formattedPem.replace("\n", "\n  ");
+
+        PrivateKey parsedKey = Pass2Key.convertStringToPrivateKey(pemWithWhitespace);
+
+        assertNotNull(parsedKey, "Parsed private key should not be null even with whitespace");
+        assertArrayEquals(originalKey.getEncoded(), parsedKey.getEncoded(),
+                "Parsed key with whitespace should match original key bytes");
+    }
+}

src/test/resources/junit-platform.properties

@@ -0,0 +1,2 @@
+junit.jupiter.execution.parallel.enabled = true
+junit.jupiter.execution.parallel.config.dynamic.factor = 1