Unit Test Security Authorization

# Advanced Authorization Testing

## Testing Expression-Based Authorization

### Complex Permission Expressions

```java
@Service
public class DocumentService {

  @PreAuthorize("hasRole('ADMIN') or authentication.principal.username == #owner")
  public Document getDocument(String owner, Long docId) {
    // get document
  }

  @PreAuthorize("hasPermission(#docId, 'Document', 'WRITE')")
  public void updateDocument(Long docId, String content) {
    // update logic
  }

  @PreAuthorize("#userId == authentication.principal.id")
  public UserProfile getUserProfile(Long userId) {
    // get profile
  }
}
```

### Tests

```java
class ExpressionBasedSecurityTest {

  @Test
  @WithMockUser(username = "alice", roles = "ADMIN")
  void shouldAllowAdminToAccessAnyDocument() {
    DocumentService service = new DocumentService();

    assertThatCode(() -> service.getDocument("bob", 1L))
      .doesNotThrowAnyException();
  }

  @Test
  @WithMockUser(username = "alice")
  void shouldAllowOwnerToAccessOwnDocument() {
    DocumentService service = new DocumentService();

    assertThatCode(() -> service.getDocument("alice", 1L))
      .doesNotThrowAnyException();
  }

  @Test
  @WithMockUser(username = "alice")
  void shouldDenyUserAccessToOtherUserDocument() {
    DocumentService service = new DocumentService();

    assertThatThrownBy(() -> service.getDocument("bob", 1L))
      .isInstanceOf(AccessDeniedException.class);
  }

  @Test
  @WithMockUser(username = "alice", id = "1")
  void shouldAllowUserToAccessOwnProfile() {
    DocumentService service = new DocumentService();

    assertThatCode(() -> service.getUserProfile(1L))
      .doesNotThrowAnyException();
  }

  @Test
  @WithMockUser(username = "alice", id = "1")
  void shouldDenyUserAccessToOtherProfile() {
    DocumentService service = new DocumentService();

    assertThatThrownBy(() -> service.getUserProfile(999L))
      .isInstanceOf(AccessDeniedException.class);
  }
}
```

## Testing Custom Permission Evaluator

### Custom Permission Evaluator Implementation

```java
@Component
public class DocumentPermissionEvaluator implements PermissionEvaluator {

  private final DocumentRepository documentRepository;

  public DocumentPermissionEvaluator(DocumentRepository documentRepository) {
    this.documentRepository = documentRepository;
  }

  @Override
  public boolean hasPermission(Authentication authentication,
                               Object targetDomainObject,
                               Object permission) {
    if (authentication == null) return false;

    Document document = (Document) targetDomainObject;
    String userUsername = authentication.getName();

    return document.getOwner().getUsername().equals(userUsername) ||
           userHasRole(authentication, "ADMIN");
  }

  @Override
  public boolean hasPermission(Authentication authentication,
                               Serializable targetId,
                               String targetType,
                               Object permission) {
    if (authentication == null) return false;
    if (!"Document".equals(targetType)) return false;

    Document document = documentRepository.findById((Long) targetId).orElse(null);
    if (document == null) return false;

    return hasPermission(authentication, document, permission);
  }

  private boolean userHasRole(Authentication authentication, String role) {
    return authentication.getAuthorities().stream()
      .anyMatch(auth -> auth.getAuthority().equals("ROLE_" + role));
  }
}
```

### Unit Tests for Custom Evaluator

```java
class DocumentPermissionEvaluatorTest {

  private DocumentPermissionEvaluator evaluator;
  private DocumentRepository documentRepository;
  private Authentication adminAuth;
  private Authentication userAuth;
  private Document document;

  @BeforeEach
  void setUp() {
    documentRepository = mock(DocumentRepository.class);
    evaluator = new DocumentPermissionEvaluator(documentRepository);

    document = new Document(1L, "Te