diff --git a/TODO_TESTS.md b/TODO_TESTS.md
new file mode 100644
index 00000000..a72c6b9b
--- /dev/null
+++ b/TODO_TESTS.md
@@ -0,0 +1,207 @@
+# Test Coverage TODO
+
+This document tracks test coverage improvements for DocuElevate. The goal is to improve overall coverage from 45% to 60%+, then iterate in 10% steps.
+
+## Current Status
+
+**Initial Coverage**: 45.09%  
+**Current Coverage**: 49.11%  
+**Progress**: +4.02%  
+**Target Coverage**: 60%+ (Phase 1), then 70%, 80%
+
+## Completed Tests
+
+### Phase 1: Low-Hanging Fruits (Target: 60%+)
+
+#### Utility Modules (0% → High Coverage) ✅
+- [x] `app/utils/encryption.py` (0% → 89.29%) ✅
+  - Test encrypt_value with various inputs
+  - Test decrypt_value with encrypted/plaintext values
+  - Test is_encrypted function
+  - Test is_encryption_available
+  - Mock cryptography library for error cases
+  
+- [x] `app/celery_worker.py` (0% → 90.62%) ✅
+  - Test task imports
+  - Test module structure
+  
+- [x] `app/tasks/uptime_kuma_tasks.py` (0% → 100%) ✅
+  - Test ping_uptime_kuma with valid URL
+  - Test skipping when URL not configured
+  - Test error handling for failed requests
+  
+- [x] `app/utils.py` (0% → Still 0%) ⚠️
+  - Simple re-export module, coverage is from actual usage
+  
+- [x] `app/frontend.py` (0% → 100%) ✅
+  - Simple re-export module, test imports work
+  
+- [x] `app/utils/config_validator.py` (0% → Still 0%) ⚠️
+  - Re-export module, coverage is from actual usage
+
+#### Low Coverage Modules (<30% → Improved)
+- [x] `app/utils/filename_utils.py` (24.62% → 81.54%) ✅
+  - Test sanitize_filename with special characters
+  - Test get_unique_filename
+  - Test extract_remote_path
+  - Test filename validation functions
+  
+- [x] `app/utils/logging.py` (42.86% → 100%) ✅
+  - Test log_task_progress function
+  - Test various log message formats
+  
+- [ ] `app/utils/oauth_helper.py` (17.50% → Target 50%+)
+  - Test OAuth URL generation
+  - Test token refresh logic
+  - Mock OAuth provider responses
+
+### Files Improved
+1. **app/utils/encryption.py**: 0% → 89.29% (+89.29%)
+2. **app/celery_worker.py**: 0% → 90.62% (+90.62%)
+3. **app/tasks/uptime_kuma_tasks.py**: 0% → 100% (+100%)
+4. **app/frontend.py**: 0% → 100% (+100%)
+5. **app/utils/filename_utils.py**: 24.62% → 81.54% (+56.92%)
+6. **app/utils/logging.py**: 42.86% → 100% (+57.14%)
+7. **app/tasks/check_credentials.py**: 0% → 23.13% (+23.13% from imports)
+8. **app/tasks/imap_tasks.py**: 0% → 15.35% (+15.35% from imports)
+
+## Phase 2: Medium Priority (Target: 70%+)
+
+### API Routes with Low Coverage
+- [ ] `app/api/azure.py` (23.08% → 60%+)
+  - Test Azure connection
+  - Test credential validation
+  - Mock Azure API responses
+  
+- [ ] `app/api/dropbox.py` (16.94% → 50%+)
+  - Test OAuth flow (mocked)
+  - Test token validation
+  - Test connection testing
+  
+- [ ] `app/api/google_drive.py` (12.94% → 50%+)
+  - Test OAuth flow (mocked)
+  - Test token validation
+  - Test drive connection
+  
+- [ ] `app/api/onedrive.py` (13.83% → 50%+)
+  - Test OAuth flow (mocked)
+  - Test token validation
+  - Test connection testing
+
+### Task Modules with Low Coverage
+- [ ] `app/tasks/convert_to_pdf.py` (13.41% → 50%+)
+  - Test PDF conversion with various formats
+  - Test Gotenberg integration (mocked)
+  - Test error handling
+  
+- [ ] `app/tasks/embed_metadata_into_pdf.py` (19.05% → 50%+)
+  - Test metadata embedding
+  - Test PDF manipulation
+  - Test error cases
+
+## Phase 3: Complex Integration Tests (Target: 80%+)
+
+### Upload Task Modules (Currently 13-36%)
+These require complex external service mocking:
+- [ ] `app/tasks/upload_to_dropbox.py` (13.45%)
+- [ ] `app/tasks/upload_to_google_drive.py` (36.00%)
+- [ ] `app/tasks/upload_to_onedrive.py` (26.32%)
+- [ ] `app/tasks/upload_to_nextcloud.py` (15.19%)
+- [ ] `app/tasks/upload_to_paperless.py` (18.60%)
+- [ ] `app/tasks/upload_to_email.py` (36.08%)
+
+### Complex Background Tasks (0-36%)
+- [ ] `app/tasks/check_credentials.py` (0%)
+  - Requires mocking multiple external services
+  - Test credential validation for each provider
+  - Test failure state management
+  - Test notification system
+  
+- [ ] `app/tasks/imap_tasks.py` (0%)
+  - Requires IMAP server mocking
+  - Test email fetching
+  - Test email parsing
+  - Test lock management with Redis
+  
+- [ ] `app/tasks/upload_with_rclone.py` (0%)
+  - Test rclone command execution
+  - Test configuration management
+  - Test error handling
+  
+- [ ] `app/tasks/extract_metadata_with_gpt.py` (28.79%)
+  - Test GPT metadata extraction
+  - Mock OpenAI API responses
+  - Test various document types
+
+### View Routes (25-61%)
+- [ ] `app/views/status.py` (25.00%)
+- [ ] `app/views/wizard.py` (38.98%)
+- [ ] `app/views/settings.py` (42.86%)
+- [ ] `app/views/google_drive.py` (42.42%)
+
+## Testing Strategy
+
+### For Low-Hanging Fruits (Phase 1)
+1. Focus on pure functions with minimal dependencies
+2. Mock external services (OpenAI, Azure, cloud storage)
+3. Test error paths and edge cases
+4. Use pytest fixtures for common setup
+
+### For Integration Tests (Phases 2-3)
+1. Create comprehensive mocks for external services
+2. Use pytest-mock for patching
+3. Test async functions with pytest-asyncio
+4. Use TestClient for API endpoint tests
+5. Mock Redis, database, and Celery for task tests
+
+## Coverage Goals by Phase
+
+| Phase | Target Coverage | Status |
+|-------|----------------|--------|
+| Phase 1: Low-Hanging Fruits | 60% | In Progress |
+| Phase 2: Medium Priority | 70% | Not Started |
+| Phase 3: Complex Integration | 80% | Not Started |
+
+## Notes
+
+- Files with 100% coverage: Keep them at 100%
+- Files with 90%+ coverage: Low priority for improvement
+- Focus on business logic, not simple re-exports
+- Mock external dependencies to avoid flaky tests
+- All tests must pass CI/CD pipeline
+- Maintain test execution time under 2 minutes for fast feedback
+
+## Files Excluded from Coverage
+
+These files are infrastructure/configuration and don't require high coverage:
+- `migrations/*` - Database migrations (excluded in pytest.ini)
+- `app/__init__.py` - Empty init files
+- `app/*/__init__.py` - Package init files
+
+## Running Tests
+
+```bash
+# Run all tests with coverage
+pytest --cov=app --cov-report=term-missing
+
+# Run tests for specific module
+pytest tests/test_encryption.py -v
+
+# Run tests with coverage report
+pytest --cov=app --cov-report=html
+open htmlcov/index.html
+
+# Run only unit tests (fast)
+pytest -m unit
+
+# Run integration tests
+pytest -m integration
+```
+
+## Contributing
+
+When adding new code:
+1. Write tests for new functionality
+2. Aim for 80%+ coverage on new files
+3. Update this TODO when completing test coverage work
+4. Run coverage report before submitting PR
diff --git a/tests/test_celery_worker.py b/tests/test_celery_worker.py
new file mode 100644
index 00000000..c9dd6655
--- /dev/null
+++ b/tests/test_celery_worker.py
@@ -0,0 +1,114 @@
+"""
+Tests for app/celery_worker.py
+
+Tests Celery worker configuration and task registration.
+Note: These tests use pytest.mark.requires_redis since they depend on Celery configuration.
+"""
+
+import pytest
+from unittest.mock import Mock, patch, MagicMock
+
+
+@pytest.mark.unit
+class TestCeleryWorkerConfiguration:
+    """Test Celery worker configuration"""
+
+    def test_celery_worker_module_imports(self):
+        """Test that celery_worker module can be imported"""
+        import app.celery_worker
+
+        assert hasattr(app.celery_worker, "celery")
+        assert hasattr(app.celery_worker, "test_task")
+
+    def test_test_task_defined(self):
+        """Test that test_task is defined"""
+        from app.celery_worker import test_task
+
+        # Task should be callable
+        assert callable(test_task)
+
+
+@pytest.mark.unit
+class TestTaskImports:
+    """Test that all tasks can be imported correctly"""
+
+    def test_process_document_imported(self):
+        """Test process_document task import"""
+        from app.celery_worker import process_document
+
+        assert callable(process_document)
+
+    def test_convert_to_pdf_imported(self):
+        """Test convert_to_pdf task import"""
+        from app.celery_worker import convert_to_pdf
+
+        assert callable(convert_to_pdf)
+
+    def test_embed_metadata_into_pdf_imported(self):
+        """Test embed_metadata_into_pdf task import"""
+        from app.celery_worker import embed_metadata_into_pdf
+
+        assert callable(embed_metadata_into_pdf)
+
+    def test_extract_metadata_with_gpt_imported(self):
+        """Test extract_metadata_with_gpt task import"""
+        from app.celery_worker import extract_metadata_with_gpt
+
+        assert callable(extract_metadata_with_gpt)
+
+    def test_send_to_all_destinations_imported(self):
+        """Test send_to_all_destinations task import"""
+        from app.celery_worker import send_to_all_destinations
+
+        assert callable(send_to_all_destinations)
+
+    def test_upload_tasks_imported(self):
+        """Test that upload tasks are imported"""
+        from app.celery_worker import (
+            upload_to_dropbox,
+            upload_to_email,
+            upload_to_ftp,
+            upload_to_google_drive,
+            upload_to_nextcloud,
+            upload_to_onedrive,
+            upload_to_paperless,
+            upload_to_s3,
+            upload_to_sftp,
+            upload_to_webdav,
+        )
+
+        # All should be callable
+        assert callable(upload_to_dropbox)
+        assert callable(upload_to_email)
+        assert callable(upload_to_ftp)
+        assert callable(upload_to_google_drive)
+        assert callable(upload_to_nextcloud)
+        assert callable(upload_to_onedrive)
+        assert callable(upload_to_paperless)
+        assert callable(upload_to_s3)
+        assert callable(upload_to_sftp)
+        assert callable(upload_to_webdav)
+
+    def test_utility_tasks_imported(self):
+        """Test utility tasks are imported"""
+        from app.celery_worker import (
+            pull_all_inboxes,
+            ping_uptime_kuma,
+            check_credentials,
+        )
+
+        assert callable(pull_all_inboxes)
+        assert callable(ping_uptime_kuma)
+        assert callable(check_credentials)
+
+    def test_processing_tasks_imported(self):
+        """Test processing tasks are imported"""
+        from app.celery_worker import (
+            process_with_azure_document_intelligence,
+            refine_text_with_gpt,
+            rotate_pdf_pages,
+        )
+
+        assert callable(process_with_azure_document_intelligence)
+        assert callable(refine_text_with_gpt)
+        assert callable(rotate_pdf_pages)
diff --git a/tests/test_encryption.py b/tests/test_encryption.py
new file mode 100644
index 00000000..686d8ed8
--- /dev/null
+++ b/tests/test_encryption.py
@@ -0,0 +1,231 @@
+"""
+Tests for app/utils/encryption.py
+
+Tests encryption/decryption functionality for sensitive settings.
+"""
+
+import pytest
+from unittest.mock import Mock, patch, MagicMock
+
+
+@pytest.mark.unit
+class TestEncryption:
+    """Test encryption utility functions"""
+
+    def test_encrypt_value_with_none(self):
+        """Test that None values are returned as-is"""
+        from app.utils.encryption import encrypt_value
+
+        result = encrypt_value(None)
+        assert result is None
+
+    def test_encrypt_value_with_empty_string(self):
+        """Test that empty strings are returned as-is"""
+        from app.utils.encryption import encrypt_value
+
+        result = encrypt_value("")
+        assert result == ""
+
+    @patch("app.utils.encryption._get_cipher_suite")
+    def test_encrypt_value_when_encryption_unavailable(self, mock_cipher):
+        """Test that plaintext is returned when encryption is unavailable"""
+        from app.utils.encryption import encrypt_value
+
+        mock_cipher.return_value = None
+        result = encrypt_value("secret_value")
+
+        # Should return plaintext with warning logged
+        assert result == "secret_value"
+
+    @patch("app.utils.encryption._get_cipher_suite")
+    def test_encrypt_value_success(self, mock_cipher):
+        """Test successful encryption"""
+        from app.utils.encryption import encrypt_value
+
+        # Mock cipher that returns encrypted bytes
+        mock_fernet = Mock()
+        mock_fernet.encrypt.return_value = b"encrypted_data"
+        mock_cipher.return_value = mock_fernet
+
+        result = encrypt_value("secret_value")
+
+        # Should have "enc:" prefix
+        assert result.startswith("enc:")
+        assert "encrypted_data" in result
+        mock_fernet.encrypt.assert_called_once()
+
+    @patch("app.utils.encryption._get_cipher_suite")
+    def test_encrypt_value_encryption_failure(self, mock_cipher):
+        """Test that encryption failures fall back to plaintext"""
+        from app.utils.encryption import encrypt_value
+
+        # Mock cipher that raises exception
+        mock_fernet = Mock()
+        mock_fernet.encrypt.side_effect = Exception("Encryption error")
+        mock_cipher.return_value = mock_fernet
+
+        result = encrypt_value("secret_value")
+
+        # Should fall back to plaintext
+        assert result == "secret_value"
+
+    def test_decrypt_value_with_none(self):
+        """Test that None values are returned as-is"""
+        from app.utils.encryption import decrypt_value
+
+        result = decrypt_value(None)
+        assert result is None
+
+    def test_decrypt_value_with_empty_string(self):
+        """Test that empty strings are returned as-is"""
+        from app.utils.encryption import decrypt_value
+
+        result = decrypt_value("")
+        assert result == ""
+
+    def test_decrypt_value_plaintext(self):
+        """Test that plaintext values without enc: prefix are returned as-is"""
+        from app.utils.encryption import decrypt_value
+
+        result = decrypt_value("plain_value")
+        assert result == "plain_value"
+
+    @patch("app.utils.encryption._get_cipher_suite")
+    def test_decrypt_value_when_encryption_unavailable(self, mock_cipher):
+        """Test decryption when cipher is unavailable"""
+        from app.utils.encryption import decrypt_value
+
+        mock_cipher.return_value = None
+        result = decrypt_value("enc:encrypted_data")
+
+        # Should return error message
+        assert result == "[ENCRYPTED - Cannot decrypt]"
+
+    @patch("app.utils.encryption._get_cipher_suite")
+    def test_decrypt_value_success(self, mock_cipher):
+        """Test successful decryption"""
+        from app.utils.encryption import decrypt_value
+
+        # Mock cipher that returns decrypted bytes
+        mock_fernet = Mock()
+        mock_fernet.decrypt.return_value = b"decrypted_value"
+        mock_cipher.return_value = mock_fernet
+
+        result = decrypt_value("enc:encrypted_data")
+
+        assert result == "decrypted_value"
+        mock_fernet.decrypt.assert_called_once()
+
+    @patch("app.utils.encryption._get_cipher_suite")
+    def test_decrypt_value_decryption_failure(self, mock_cipher):
+        """Test that decryption failures return error message"""
+        from app.utils.encryption import decrypt_value
+
+        # Mock cipher that raises exception
+        mock_fernet = Mock()
+        mock_fernet.decrypt.side_effect = Exception("Decryption error")
+        mock_cipher.return_value = mock_fernet
+
+        result = decrypt_value("enc:bad_data")
+
+        # Should return error message
+        assert result == "[DECRYPTION FAILED]"
+
+    def test_is_encrypted_with_encrypted_value(self):
+        """Test is_encrypted returns True for encrypted values"""
+        from app.utils.encryption import is_encrypted
+
+        assert is_encrypted("enc:some_encrypted_data") is True
+
+    def test_is_encrypted_with_plaintext(self):
+        """Test is_encrypted returns False for plaintext"""
+        from app.utils.encryption import is_encrypted
+
+        assert is_encrypted("plain_value") is False
+
+    def test_is_encrypted_with_none(self):
+        """Test is_encrypted returns False for None"""
+        from app.utils.encryption import is_encrypted
+
+        assert is_encrypted(None) is False
+
+    def test_is_encrypted_with_empty_string(self):
+        """Test is_encrypted returns False for empty string"""
+        from app.utils.encryption import is_encrypted
+
+        assert is_encrypted("") is False
+
+    def test_is_encrypted_with_non_string(self):
+        """Test is_encrypted returns False for non-string types"""
+        from app.utils.encryption import is_encrypted
+
+        assert is_encrypted(123) is False
+        assert is_encrypted([]) is False
+        assert is_encrypted({}) is False
+
+    @patch("app.utils.encryption._get_cipher_suite")
+    def test_is_encryption_available_true(self, mock_cipher):
+        """Test is_encryption_available when cryptography is available"""
+        from app.utils.encryption import is_encryption_available
+
+        mock_cipher.return_value = Mock()  # Non-None cipher
+        assert is_encryption_available() is True
+
+    @patch("app.utils.encryption._get_cipher_suite")
+    def test_is_encryption_available_false(self, mock_cipher):
+        """Test is_encryption_available when cryptography is not available"""
+        from app.utils.encryption import is_encryption_available
+
+        mock_cipher.return_value = None
+        assert is_encryption_available() is False
+
+
+@pytest.mark.unit
+class TestGetCipherSuite:
+    """Test the _get_cipher_suite internal function"""
+
+    def test_cipher_suite_caching(self):
+        """Test that cipher suite is cached after first call"""
+        import app.utils.encryption
+
+        # First call
+        result1 = app.utils.encryption._get_cipher_suite()
+
+        # Second call should return same instance (cached)
+        result2 = app.utils.encryption._get_cipher_suite()
+
+        # Both calls should return the same object (cached)
+        assert result1 is result2
+
+
+@pytest.mark.unit
+class TestEncryptionIntegration:
+    """Integration tests for encrypt/decrypt cycle"""
+
+    @patch("app.utils.encryption._get_cipher_suite")
+    def test_encrypt_decrypt_cycle(self, mock_cipher):
+        """Test that encrypting and then decrypting returns original value"""
+        from app.utils.encryption import encrypt_value, decrypt_value
+
+        # Mock a simple reversible encryption
+        mock_fernet = Mock()
+
+        # Simulate encryption: just add a prefix
+        def mock_encrypt(data):
+            return b"ENCRYPTED_" + data
+
+        # Simulate decryption: remove the prefix
+        def mock_decrypt(data):
+            return data.replace(b"ENCRYPTED_", b"")
+
+        mock_fernet.encrypt = mock_encrypt
+        mock_fernet.decrypt = mock_decrypt
+        mock_cipher.return_value = mock_fernet
+
+        original = "my_secret_password"
+        encrypted = encrypt_value(original)
+        decrypted = decrypt_value(encrypted)
+
+        assert encrypted != original
+        assert encrypted.startswith("enc:")
+        assert decrypted == original
diff --git a/tests/test_filename_utils.py b/tests/test_filename_utils.py
new file mode 100644
index 00000000..3fb9df7d
--- /dev/null
+++ b/tests/test_filename_utils.py
@@ -0,0 +1,259 @@
+"""
+Tests for app/utils/filename_utils.py
+
+Tests filename sanitization and manipulation functions.
+"""
+
+import pytest
+import os
+from pathlib import Path
+from unittest.mock import Mock, patch
+from datetime import datetime
+
+
+@pytest.mark.unit
+class TestFilenameSanitization:
+    """Test filename sanitization functions"""
+
+    def test_sanitize_filename_basic(self):
+        """Test basic filename sanitization"""
+        from app.utils.filename_utils import sanitize_filename
+
+        # Basic valid filename
+        result = sanitize_filename("document.pdf")
+        assert result == "document.pdf"
+
+    def test_sanitize_filename_with_spaces(self):
+        """Test sanitization of filenames with spaces"""
+        from app.utils.filename_utils import sanitize_filename
+
+        result = sanitize_filename("my document file.pdf")
+        # Spaces should be preserved
+        assert "my" in result
+        assert "document" in result
+        assert "file.pdf" in result
+
+    def test_sanitize_filename_with_special_characters(self):
+        """Test sanitization removes or replaces special characters"""
+        from app.utils.filename_utils import sanitize_filename
+
+        result = sanitize_filename("file:with*special?chars.pdf")
+        # Special characters should be replaced with underscores
+        assert ":" not in result
+        assert "*" not in result
+        assert "?" not in result
+        assert "_" in result
+
+    def test_sanitize_filename_with_path_separators(self):
+        """Test that path separators are handled"""
+        from app.utils.filename_utils import sanitize_filename
+
+        result = sanitize_filename("../../../etc/passwd")
+        # Path traversal characters should be replaced
+        assert ".." not in result or result.count("..") < 3
+
+    def test_sanitize_filename_empty_string(self):
+        """Test sanitization of empty string"""
+        from app.utils.filename_utils import sanitize_filename
+
+        result = sanitize_filename("")
+        # Should return a valid string (default name with timestamp)
+        assert isinstance(result, str)
+        assert len(result) > 0
+        assert "document" in result
+
+    def test_sanitize_filename_only_periods(self):
+        """Test sanitization of only periods"""
+        from app.utils.filename_utils import sanitize_filename
+
+        result = sanitize_filename("...")
+        # Should return a default name
+        assert isinstance(result, str)
+        assert len(result) > 0
+        assert "document" in result
+
+    def test_sanitize_filename_leading_trailing_spaces(self):
+        """Test sanitization trims leading/trailing spaces"""
+        from app.utils.filename_utils import sanitize_filename
+
+        result = sanitize_filename("  filename.pdf  ")
+        assert result == "filename.pdf"
+
+    def test_sanitize_filename_multiple_underscores(self):
+        """Test sanitization collapses multiple underscores"""
+        from app.utils.filename_utils import sanitize_filename
+
+        result = sanitize_filename("file____name.pdf")
+        assert "____" not in result
+        assert result == "file_name.pdf"
+
+
+@pytest.mark.unit
+class TestUniqueFilenameGeneration:
+    """Test unique filename generation"""
+
+    def test_get_unique_filename_no_collision(self):
+        """Test that original filename is returned when no collision"""
+        from app.utils.filename_utils import get_unique_filename
+
+        # Mock check_exists_func to return False (file doesn't exist)
+        check_func = Mock(return_value=False)
+
+        result = get_unique_filename("/tmp/document.pdf", check_exists_func=check_func)
+        assert result == "/tmp/document.pdf"
+        check_func.assert_called_once_with("/tmp/document.pdf")
+
+    def test_get_unique_filename_with_collision(self):
+        """Test that unique filename is generated on collision"""
+        from app.utils.filename_utils import get_unique_filename
+
+        # Mock check_exists_func to return True for original, False for timestamped
+        def check_func(path):
+            return path == "/tmp/document.pdf"
+
+        result = get_unique_filename("/tmp/document.pdf", check_exists_func=check_func)
+        assert result != "/tmp/document.pdf"
+        assert "document" in result
+        assert ".pdf" in result
+
+    def test_get_unique_filename_uses_timestamp(self):
+        """Test that timestamp is added on collision"""
+        from app.utils.filename_utils import get_unique_filename
+
+        # First file exists
+        check_func = Mock(side_effect=[True, False])
+
+        result = get_unique_filename("/tmp/test.pdf", check_exists_func=check_func)
+        assert result != "/tmp/test.pdf"
+        assert "test_" in result
+        assert ".pdf" in result
+
+    def test_get_unique_filename_falls_back_to_uuid(self):
+        """Test UUID fallback when timestamp collision occurs"""
+        from app.utils.filename_utils import get_unique_filename
+
+        # Original and timestamp both exist
+        check_func = Mock(side_effect=[True, True, False])
+
+        result = get_unique_filename("/tmp/test.pdf", check_exists_func=check_func)
+        assert result != "/tmp/test.pdf"
+        assert "test_" in result
+        assert ".pdf" in result
+
+    def test_get_unique_filename_default_check_function(self):
+        """Test that os.path.exists is used by default"""
+        from app.utils.filename_utils import get_unique_filename
+
+        # Use actual filesystem check
+        result = get_unique_filename("/tmp/nonexistent_file_12345.pdf")
+        # Should return original since file doesn't exist
+        assert result == "/tmp/nonexistent_file_12345.pdf"
+
+
+@pytest.mark.unit
+class TestExtractRemotePath:
+    """Test remote path extraction"""
+
+    def test_extract_remote_path_basic(self):
+        """Test basic remote path extraction"""
+        from app.utils.filename_utils import extract_remote_path
+
+        file_path = "/home/user/docs/file.pdf"
+        base_dir = "/home/user"
+        remote_base = "Documents"
+
+        result = extract_remote_path(file_path, base_dir, remote_base)
+        assert result == "Documents/docs/file.pdf"
+
+    def test_extract_remote_path_without_remote_base(self):
+        """Test remote path extraction without remote base"""
+        from app.utils.filename_utils import extract_remote_path
+
+        file_path = "/home/user/docs/file.pdf"
+        base_dir = "/home/user"
+
+        result = extract_remote_path(file_path, base_dir, "")
+        assert result == "docs/file.pdf"
+
+    def test_extract_remote_path_skips_processed_dir(self):
+        """Test that 'processed' directory is skipped"""
+        from app.utils.filename_utils import extract_remote_path
+
+        file_path = "/home/user/processed/docs/file.pdf"
+        base_dir = "/home/user"
+
+        result = extract_remote_path(file_path, base_dir, "")
+        assert "processed" not in result
+        assert result == "docs/file.pdf"
+
+    def test_extract_remote_path_with_absolute_remote_base(self):
+        """Test remote path extraction with absolute remote base"""
+        from app.utils.filename_utils import extract_remote_path
+
+        file_path = "/home/user/docs/file.pdf"
+        base_dir = "/home/user"
+        remote_base = "/Documents"
+
+        result = extract_remote_path(file_path, base_dir, remote_base)
+        # Leading slash should be stripped
+        assert result == "Documents/docs/file.pdf"
+
+    def test_extract_remote_path_file_outside_base(self):
+        """Test handling of file outside base directory"""
+        from app.utils.filename_utils import extract_remote_path
+
+        file_path = "/other/path/file.pdf"
+        base_dir = "/home/user"
+
+        result = extract_remote_path(file_path, base_dir, "")
+        # Should just use filename
+        assert result == "file.pdf"
+
+    def test_extract_remote_path_uses_forward_slashes(self):
+        """Test that result uses forward slashes"""
+        from app.utils.filename_utils import extract_remote_path
+
+        file_path = "/home/user/docs/subfolder/file.pdf"
+        base_dir = "/home/user"
+
+        result = extract_remote_path(file_path, base_dir, "")
+        # Should use forward slashes for cloud service compatibility
+        assert "/" in result
+        assert "\\" not in result
+
+
+@pytest.mark.unit
+class TestFilenameUtilsEdgeCases:
+    """Test edge cases in filename utilities"""
+
+    def test_very_long_filename(self):
+        """Test handling of very long filenames"""
+        from app.utils.filename_utils import sanitize_filename
+
+        long_name = "a" * 300 + ".pdf"
+        result = sanitize_filename(long_name)
+        # Should handle long filenames
+        assert isinstance(result, str)
+        assert len(result) > 0
+
+    def test_filename_with_multiple_dots(self):
+        """Test filename with multiple dots"""
+        from app.utils.filename_utils import sanitize_filename
+
+        result = sanitize_filename("my.document.file.name.pdf")
+        assert isinstance(result, str)
+        assert ".pdf" in result
+        assert result == "my.document.file.name.pdf"
+
+    def test_sanitize_filename_windows_reserved_chars(self):
+        """Test sanitization of Windows reserved characters"""
+        from app.utils.filename_utils import sanitize_filename
+
+        result = sanitize_filename('file<>:"|?*.pdf')
+        # All reserved chars should be replaced
+        assert "<" not in result
+        assert ">" not in result
+        assert ":" not in result
+        assert '"' not in result
+        assert "|" not in result
+        assert "?" not in result
diff --git a/tests/test_logging_utils.py b/tests/test_logging_utils.py
new file mode 100644
index 00000000..81dfbcfb
--- /dev/null
+++ b/tests/test_logging_utils.py
@@ -0,0 +1,176 @@
+"""
+Tests for app/utils/logging.py
+
+Tests task progress logging functionality.
+"""
+
+import pytest
+from unittest.mock import Mock, patch, MagicMock
+
+
+@pytest.mark.unit
+class TestTaskLogging:
+    """Test task progress logging"""
+
+    @patch("app.utils.logging.SessionLocal")
+    @patch("app.utils.logging.ProcessingLog")
+    def test_log_task_progress_basic(self, mock_processing_log, mock_session_local):
+        """Test basic task progress logging"""
+        from app.utils.logging import log_task_progress
+
+        # Mock database session
+        mock_db = MagicMock()
+        mock_session_local.return_value.__enter__.return_value = mock_db
+
+        # Mock ProcessingLog model
+        mock_log_entry = Mock()
+        mock_processing_log.return_value = mock_log_entry
+
+        # Call the function
+        log_task_progress(
+            task_id="task-123",
+            step_name="processing",
+            status="started",
+            message="Processing document",
+            file_id=456,
+        )
+
+        # Verify ProcessingLog was created with correct parameters
+        mock_processing_log.assert_called_once_with(
+            task_id="task-123",
+            step_name="processing",
+            status="started",
+            message="Processing document",
+            file_id=456,
+        )
+
+        # Verify database operations
+        mock_db.add.assert_called_once_with(mock_log_entry)
+        mock_db.commit.assert_called_once()
+
+    @patch("app.utils.logging.SessionLocal")
+    @patch("app.utils.logging.ProcessingLog")
+    def test_log_task_progress_without_message(self, mock_processing_log, mock_session_local):
+        """Test logging without message"""
+        from app.utils.logging import log_task_progress
+
+        mock_db = MagicMock()
+        mock_session_local.return_value.__enter__.return_value = mock_db
+
+        mock_log_entry = Mock()
+        mock_processing_log.return_value = mock_log_entry
+
+        # Call without message
+        log_task_progress(
+            task_id="task-456", step_name="upload", status="completed", message=None, file_id=None
+        )
+
+        # Verify called with None for optional parameters
+        mock_processing_log.assert_called_once_with(
+            task_id="task-456", step_name="upload", status="completed", message=None, file_id=None
+        )
+
+        mock_db.add.assert_called_once()
+        mock_db.commit.assert_called_once()
+
+    @patch("app.utils.logging.SessionLocal")
+    @patch("app.utils.logging.ProcessingLog")
+    def test_log_task_progress_without_file_id(self, mock_processing_log, mock_session_local):
+        """Test logging without file_id"""
+        from app.utils.logging import log_task_progress
+
+        mock_db = MagicMock()
+        mock_session_local.return_value.__enter__.return_value = mock_db
+
+        mock_log_entry = Mock()
+        mock_processing_log.return_value = mock_log_entry
+
+        # Call without file_id
+        log_task_progress(
+            task_id="task-789", step_name="metadata", status="running", message="Extracting metadata"
+        )
+
+        # file_id should default to None
+        mock_processing_log.assert_called_once()
+        call_args = mock_processing_log.call_args
+        assert call_args[1]["task_id"] == "task-789"
+        assert call_args[1]["step_name"] == "metadata"
+        assert call_args[1]["status"] == "running"
+
+        mock_db.add.assert_called_once()
+        mock_db.commit.assert_called_once()
+
+    @patch("app.utils.logging.SessionLocal")
+    @patch("app.utils.logging.ProcessingLog")
+    def test_log_task_progress_all_parameters(self, mock_processing_log, mock_session_local):
+        """Test logging with all parameters"""
+        from app.utils.logging import log_task_progress
+
+        mock_db = MagicMock()
+        mock_session_local.return_value.__enter__.return_value = mock_db
+
+        mock_log_entry = Mock()
+        mock_processing_log.return_value = mock_log_entry
+
+        # Call with all parameters
+        log_task_progress(
+            task_id="task-complete",
+            step_name="finalization",
+            status="success",
+            message="Document processed successfully",
+            file_id=999,
+        )
+
+        mock_processing_log.assert_called_once_with(
+            task_id="task-complete",
+            step_name="finalization",
+            status="success",
+            message="Document processed successfully",
+            file_id=999,
+        )
+
+        mock_db.add.assert_called_once()
+        mock_db.commit.assert_called_once()
+
+    @patch("app.utils.logging.SessionLocal")
+    @patch("app.utils.logging.ProcessingLog")
+    def test_log_task_progress_session_context_manager(self, mock_processing_log, mock_session_local):
+        """Test that database session is properly managed with context manager"""
+        from app.utils.logging import log_task_progress
+
+        mock_session_context = MagicMock()
+        mock_session_local.return_value = mock_session_context
+
+        mock_db = MagicMock()
+        mock_session_context.__enter__.return_value = mock_db
+
+        mock_log_entry = Mock()
+        mock_processing_log.return_value = mock_log_entry
+
+        log_task_progress(task_id="test", step_name="test", status="test")
+
+        # Verify context manager was used
+        mock_session_context.__enter__.assert_called_once()
+        mock_session_context.__exit__.assert_called_once()
+
+    @patch("app.utils.logging.SessionLocal")
+    @patch("app.utils.logging.ProcessingLog")
+    def test_log_task_progress_with_different_statuses(self, mock_processing_log, mock_session_local):
+        """Test logging with various status values"""
+        from app.utils.logging import log_task_progress
+
+        mock_db = MagicMock()
+        mock_session_local.return_value.__enter__.return_value = mock_db
+
+        mock_log_entry = Mock()
+        mock_processing_log.return_value = mock_log_entry
+
+        statuses = ["pending", "processing", "completed", "failed", "error"]
+
+        for status in statuses:
+            log_task_progress(task_id=f"task-{status}", step_name="test", status=status)
+
+            # Should be called for each status
+            assert mock_processing_log.called
+            mock_db.add.assert_called()
+            mock_db.commit.assert_called()
diff --git a/tests/test_reexports.py b/tests/test_reexports.py
new file mode 100644
index 00000000..cd118b12
--- /dev/null
+++ b/tests/test_reexports.py
@@ -0,0 +1,132 @@
+"""
+Tests for simple re-export modules (app/utils.py, app/frontend.py, app/utils/config_validator.py)
+
+These modules are simple re-exports of functions from other modules.
+We test that imports work correctly.
+"""
+
+import pytest
+
+
+@pytest.mark.unit
+class TestUtilsReexports:
+    """Test that app/utils.py re-exports work correctly"""
+
+    def test_hash_file_import(self):
+        """Test that hash_file can be imported from app.utils"""
+        from app.utils import hash_file
+
+        # Function should exist and be callable
+        assert callable(hash_file)
+
+    def test_log_task_progress_import(self):
+        """Test that log_task_progress can be imported from app.utils"""
+        from app.utils import log_task_progress
+
+        # Function should exist and be callable
+        assert callable(log_task_progress)
+
+    def test_utils_module_is_backward_compatible(self):
+        """Test that utils module maintains backward compatibility"""
+        # The module comment says it's deprecated but maintains compatibility
+        import app.utils
+
+        # Module should exist and have expected attributes
+        assert hasattr(app.utils, "hash_file")
+        assert hasattr(app.utils, "log_task_progress")
+
+
+@pytest.mark.unit
+class TestFrontendReexports:
+    """Test that app/frontend.py re-exports work correctly"""
+
+    def test_router_import(self):
+        """Test that router can be imported from app.frontend"""
+        from app.frontend import router
+
+        # Router should exist
+        assert router is not None
+
+    def test_frontend_module_imports(self):
+        """Test that frontend module can be imported"""
+        import app.frontend
+
+        # Module should exist and have router
+        assert hasattr(app.frontend, "router")
+
+
+@pytest.mark.unit
+class TestConfigValidatorReexports:
+    """Test that app/utils/config_validator.py re-exports work correctly"""
+
+    def test_validate_email_config_import(self):
+        """Test validate_email_config import"""
+        from app.utils.config_validator import validate_email_config
+
+        assert callable(validate_email_config)
+
+    def test_validate_storage_configs_import(self):
+        """Test validate_storage_configs import"""
+        from app.utils.config_validator import validate_storage_configs
+
+        assert callable(validate_storage_configs)
+
+    def test_validate_notification_config_import(self):
+        """Test validate_notification_config import"""
+        from app.utils.config_validator import validate_notification_config
+
+        assert callable(validate_notification_config)
+
+    def test_mask_sensitive_value_import(self):
+        """Test mask_sensitive_value import"""
+        from app.utils.config_validator import mask_sensitive_value
+
+        assert callable(mask_sensitive_value)
+
+    def test_get_provider_status_import(self):
+        """Test get_provider_status import"""
+        from app.utils.config_validator import get_provider_status
+
+        assert callable(get_provider_status)
+
+    def test_get_settings_for_display_import(self):
+        """Test get_settings_for_display import"""
+        from app.utils.config_validator import get_settings_for_display
+
+        assert callable(get_settings_for_display)
+
+    def test_dump_all_settings_import(self):
+        """Test dump_all_settings import"""
+        from app.utils.config_validator import dump_all_settings
+
+        assert callable(dump_all_settings)
+
+    def test_check_all_configs_import(self):
+        """Test check_all_configs import"""
+        from app.utils.config_validator import check_all_configs
+
+        assert callable(check_all_configs)
+
+    def test_config_validator_all_exports(self):
+        """Test that __all__ contains expected exports"""
+        from app.utils import config_validator
+
+        expected_exports = [
+            "validate_email_config",
+            "validate_storage_configs",
+            "validate_notification_config",
+            "mask_sensitive_value",
+            "get_provider_status",
+            "get_settings_for_display",
+            "dump_all_settings",
+            "check_all_configs",
+        ]
+
+        # Check that __all__ is defined and contains expected items
+        if hasattr(config_validator, "__all__"):
+            for export in expected_exports:
+                assert export in config_validator.__all__
+
+        # Also check direct imports work
+        for export in expected_exports:
+            assert hasattr(config_validator, export)
diff --git a/tests/test_uptime_kuma.py b/tests/test_uptime_kuma.py
new file mode 100644
index 00000000..8dee281e
--- /dev/null
+++ b/tests/test_uptime_kuma.py
@@ -0,0 +1,163 @@
+"""
+Tests for app/tasks/uptime_kuma_tasks.py
+
+Tests Uptime Kuma health check ping functionality.
+"""
+
+import pytest
+from unittest.mock import Mock, patch, MagicMock
+import requests
+
+
+@pytest.mark.unit
+class TestUptimeKumaTasks:
+    """Test Uptime Kuma ping task"""
+
+    @patch("app.tasks.uptime_kuma_tasks.settings")
+    def test_ping_uptime_kuma_no_url_configured(self, mock_settings):
+        """Test that task does nothing when URL is not configured"""
+        from app.tasks.uptime_kuma_tasks import ping_uptime_kuma
+
+        mock_settings.uptime_kuma_url = None
+
+        result = ping_uptime_kuma()
+
+        # Should return None and not make any requests
+        assert result is None
+
+    @patch("app.tasks.uptime_kuma_tasks.requests.get")
+    @patch("app.tasks.uptime_kuma_tasks.settings")
+    def test_ping_uptime_kuma_success(self, mock_settings, mock_get):
+        """Test successful ping to Uptime Kuma"""
+        from app.tasks.uptime_kuma_tasks import ping_uptime_kuma
+
+        mock_settings.uptime_kuma_url = "https://uptime.example.com/ping/123"
+
+        # Mock successful response
+        mock_response = Mock()
+        mock_response.status_code = 200
+        mock_response.raise_for_status = Mock()
+        mock_get.return_value = mock_response
+
+        result = ping_uptime_kuma()
+
+        # Should return True on success
+        assert result is True
+        mock_get.assert_called_once_with(
+            "https://uptime.example.com/ping/123", timeout=10
+        )
+        mock_response.raise_for_status.assert_called_once()
+
+    @patch("app.tasks.uptime_kuma_tasks.requests.get")
+    @patch("app.tasks.uptime_kuma_tasks.settings")
+    def test_ping_uptime_kuma_connection_error(self, mock_settings, mock_get):
+        """Test handling of connection errors"""
+        from app.tasks.uptime_kuma_tasks import ping_uptime_kuma
+
+        mock_settings.uptime_kuma_url = "https://uptime.example.com/ping/123"
+
+        # Mock connection error
+        mock_get.side_effect = requests.exceptions.ConnectionError("Connection refused")
+
+        result = ping_uptime_kuma()
+
+        # Should return False on error
+        assert result is False
+        mock_get.assert_called_once()
+
+    @patch("app.tasks.uptime_kuma_tasks.requests.get")
+    @patch("app.tasks.uptime_kuma_tasks.settings")
+    def test_ping_uptime_kuma_timeout(self, mock_settings, mock_get):
+        """Test handling of request timeout"""
+        from app.tasks.uptime_kuma_tasks import ping_uptime_kuma
+
+        mock_settings.uptime_kuma_url = "https://uptime.example.com/ping/123"
+
+        # Mock timeout error
+        mock_get.side_effect = requests.exceptions.Timeout("Request timed out")
+
+        result = ping_uptime_kuma()
+
+        # Should return False on timeout
+        assert result is False
+        mock_get.assert_called_once()
+
+    @patch("app.tasks.uptime_kuma_tasks.requests.get")
+    @patch("app.tasks.uptime_kuma_tasks.settings")
+    def test_ping_uptime_kuma_http_error(self, mock_settings, mock_get):
+        """Test handling of HTTP errors (4xx, 5xx)"""
+        from app.tasks.uptime_kuma_tasks import ping_uptime_kuma
+
+        mock_settings.uptime_kuma_url = "https://uptime.example.com/ping/123"
+
+        # Mock HTTP error
+        mock_response = Mock()
+        mock_response.status_code = 500
+        mock_response.raise_for_status.side_effect = requests.exceptions.HTTPError(
+            "500 Server Error"
+        )
+        mock_get.return_value = mock_response
+
+        result = ping_uptime_kuma()
+
+        # Should return False on HTTP error
+        assert result is False
+        mock_get.assert_called_once()
+
+    @patch("app.tasks.uptime_kuma_tasks.requests.get")
+    @patch("app.tasks.uptime_kuma_tasks.settings")
+    def test_ping_uptime_kuma_generic_request_exception(self, mock_settings, mock_get):
+        """Test handling of generic request exceptions"""
+        from app.tasks.uptime_kuma_tasks import ping_uptime_kuma
+
+        mock_settings.uptime_kuma_url = "https://uptime.example.com/ping/123"
+
+        # Mock generic request exception
+        mock_get.side_effect = requests.exceptions.RequestException("Generic error")
+
+        result = ping_uptime_kuma()
+
+        # Should return False on any request exception
+        assert result is False
+        mock_get.assert_called_once()
+
+    @patch("app.tasks.uptime_kuma_tasks.requests.get")
+    @patch("app.tasks.uptime_kuma_tasks.settings")
+    def test_ping_uptime_kuma_empty_url(self, mock_settings, mock_get):
+        """Test handling of empty URL string"""
+        from app.tasks.uptime_kuma_tasks import ping_uptime_kuma
+
+        mock_settings.uptime_kuma_url = ""
+
+        result = ping_uptime_kuma()
+
+        # Should return None and not make any requests
+        assert result is None
+        mock_get.assert_not_called()
+
+    @patch("app.tasks.uptime_kuma_tasks.requests.get")
+    @patch("app.tasks.uptime_kuma_tasks.settings")
+    def test_ping_uptime_kuma_with_various_status_codes(self, mock_settings, mock_get):
+        """Test successful ping with various 2xx status codes"""
+        from app.tasks.uptime_kuma_tasks import ping_uptime_kuma
+
+        mock_settings.uptime_kuma_url = "https://uptime.example.com/ping/123"
+
+        # Test with 200 OK
+        mock_response = Mock()
+        mock_response.status_code = 200
+        mock_response.raise_for_status = Mock()
+        mock_get.return_value = mock_response
+
+        result = ping_uptime_kuma()
+        assert result is True
+
+        # Test with 204 No Content
+        mock_response.status_code = 204
+        result = ping_uptime_kuma()
+        assert result is True
+
+        # Test with 202 Accepted
+        mock_response.status_code = 202
+        result = ping_uptime_kuma()
+        assert result is True