diff --git a/tests/test_auto_save.py b/tests/test_auto_save.py
new file mode 100644
index 0000000..ee0e04c
--- /dev/null
+++ b/tests/test_auto_save.py
@@ -0,0 +1,253 @@
+"""Tests for auto-save and backup system."""
+
+import pytest
+import tempfile
+import os
+import shutil
+from unittest.mock import MagicMock, patch
+from datetime import datetime
+import pandas as pd
+
+from src.auto_save import AutoSaveManager
+
+
+class TestAutoSaveManager:
+    """Test cases for AutoSaveManager class."""
+
+    def setup_method(self):
+        """Set up test fixtures."""
+        # Create temporary directories for testing
+        self.test_dir = tempfile.mkdtemp()
+        self.backup_dir = os.path.join(self.test_dir, "backups")
+        self.test_data_file = os.path.join(self.test_dir, "test_data.csv")
+
+        # Create test data file
+        test_data = pd.DataFrame({
+            'Date': ['2024-01-01', '2024-01-02'],
+            'Notes': ['Test note 1', 'Test note 2']
+        })
+        test_data.to_csv(self.test_data_file, index=False)
+
+        # Mock callbacks
+        self.mock_status_callback = MagicMock()
+        self.mock_error_callback = MagicMock()
+
+        # Create AutoSaveManager instance
+        self.auto_save = AutoSaveManager(
+            data_file_path=self.test_data_file,
+            backup_dir=self.backup_dir,
+            status_callback=self.mock_status_callback,
+            error_callback=self.mock_error_callback,
+            interval_minutes=0.1,  # Very short interval for testing
+            max_backups=3
+        )
+
+    def teardown_method(self):
+        """Clean up test fixtures."""
+        if hasattr(self, 'auto_save'):
+            self.auto_save.stop()
+        if os.path.exists(self.test_dir):
+            shutil.rmtree(self.test_dir)
+
+    def test_initialization(self):
+        """Test AutoSaveManager initialization."""
+        assert self.auto_save.data_file_path == self.test_data_file
+        assert self.auto_save.backup_dir == self.backup_dir
+        assert self.auto_save.interval_minutes == 0.1
+        assert self.auto_save.max_backups == 3
+        assert not self.auto_save.is_running
+
+    def test_backup_directory_creation(self):
+        """Test that backup directory is created."""
+        # Directory should be created during initialization
+        assert os.path.exists(self.backup_dir)
+        assert os.path.isdir(self.backup_dir)
+
+    def test_create_backup(self):
+        """Test backup creation."""
+        backup_file = self.auto_save.create_backup("test_backup")
+
+        # Verify backup file exists
+        assert os.path.exists(backup_file)
+        assert backup_file.startswith(self.backup_dir)
+        assert "test_backup" in backup_file
+
+        # Verify backup content matches original
+        original_data = pd.read_csv(self.test_data_file)
+        backup_data = pd.read_csv(backup_file)
+        pd.testing.assert_frame_equal(original_data, backup_data)
+
+    def test_create_backup_nonexistent_file(self):
+        """Test backup creation when source file doesn't exist."""
+        auto_save = AutoSaveManager(
+            data_file_path="/nonexistent/file.csv",
+            backup_dir=self.backup_dir,
+            status_callback=self.mock_status_callback,
+            error_callback=self.mock_error_callback
+        )
+
+        backup_file = auto_save.create_backup("test")
+        assert backup_file is None
+
+        # Error callback should have been called
+        self.mock_error_callback.assert_called()
+
+    def test_cleanup_old_backups(self):
+        """Test cleanup of old backups."""
+        # Create more backups than max_backups
+        backup_files = []
+        for i in range(5):
+            backup_file = self.auto_save.create_backup(f"test_{i}")
+            backup_files.append(backup_file)
+
+        # Perform cleanup
+        self.auto_save._cleanup_old_backups()
+
+        # Should only have max_backups files remaining
+        remaining_files = [f for f in backup_files if os.path.exists(f)]
+        assert len(remaining_files) <= self.auto_save.max_backups
+
+    def test_start_and_stop(self):
+        """Test starting and stopping auto-save."""
+        # Start auto-save
+        self.auto_save.start()
+        assert self.auto_save.is_running
+
+        # Stop auto-save
+        self.auto_save.stop()
+        assert not self.auto_save.is_running
+
+    def test_get_backup_files(self):
+        """Test getting list of backup files."""
+        # Create some backups
+        self.auto_save.create_backup("backup1")
+        self.auto_save.create_backup("backup2")
+
+        backup_files = self.auto_save.get_backup_files()
+
+        assert len(backup_files) >= 2
+        assert all(os.path.exists(f) for f in backup_files)
+        assert all(f.endswith('.csv') for f in backup_files)
+
+    def test_restore_from_backup(self):
+        """Test restoring from backup."""
+        # Create a backup
+        backup_file = self.auto_save.create_backup("test_restore")
+
+        # Modify original file
+        modified_data = pd.DataFrame({
+            'Date': ['2024-01-03'],
+            'Notes': ['Modified note']
+        })
+        modified_data.to_csv(self.test_data_file, index=False)
+
+        # Restore from backup
+        success = self.auto_save.restore_from_backup(backup_file)
+        assert success
+
+        # Verify restoration
+        restored_data = pd.read_csv(self.test_data_file)
+        assert len(restored_data) == 2  # Original had 2 rows
+        assert 'Test note 1' in restored_data['Notes'].values
+
+    def test_restore_from_nonexistent_backup(self):
+        """Test restoring from nonexistent backup."""
+        success = self.auto_save.restore_from_backup("/nonexistent/backup.csv")
+        assert not success
+        self.mock_error_callback.assert_called()
+
+    def test_backup_filename_format(self):
+        """Test backup filename format."""
+        backup_file = self.auto_save.create_backup("test_format")
+
+        filename = os.path.basename(backup_file)
+
+        # Should contain source filename, suffix, and timestamp
+        assert "test_data" in filename
+        assert "test_format" in filename
+        assert filename.endswith('.csv')
+
+        # Should have timestamp in format
+        assert len(filename.split('_')) >= 4  # name_suffix_date_time.csv
+
+    def test_backup_with_special_characters(self):
+        """Test backup creation with special characters in suffix."""
+        backup_file = self.auto_save.create_backup("test with spaces & symbols!")
+
+        assert os.path.exists(backup_file)
+        # Special characters should be handled appropriately
+        assert os.path.isfile(backup_file)
+
+    def test_concurrent_backup_operations(self):
+        """Test that concurrent backup operations don't interfere."""
+        # This tests thread safety (basic test)
+        backup1 = self.auto_save.create_backup("concurrent1")
+        backup2 = self.auto_save.create_backup("concurrent2")
+
+        assert backup1 != backup2
+        assert os.path.exists(backup1)
+        assert os.path.exists(backup2)
+
+    def test_error_handling_during_backup(self):
+        """Test error handling during backup operations."""
+        # Test with permission error
+        with patch('shutil.copy2', side_effect=PermissionError("Permission denied")):
+            backup_file = self.auto_save.create_backup("permission_test")
+            assert backup_file is None
+            self.mock_error_callback.assert_called()
+
+    def test_auto_save_integration(self):
+        """Test integration of auto-save functionality."""
+        # Start auto-save
+        self.auto_save.start()
+
+        # Wait a short time for at least one auto-save cycle
+        import time
+        time.sleep(0.2)  # Wait longer than interval
+
+        # Should have created startup backup
+        backup_files = self.auto_save.get_backup_files()
+        assert len(backup_files) > 0
+
+        # Stop auto-save
+        self.auto_save.stop()
+
+    def test_status_callback_integration(self):
+        """Test status callback integration."""
+        self.auto_save.create_backup("status_test")
+
+        # Status callback should have been called
+        self.mock_status_callback.assert_called()
+        call_args = self.mock_status_callback.call_args[0]
+        assert "backup" in call_args[0].lower()
+
+    def test_backup_size_validation(self):
+        """Test that backups have reasonable size."""
+        backup_file = self.auto_save.create_backup("size_test")
+
+        original_size = os.path.getsize(self.test_data_file)
+        backup_size = os.path.getsize(backup_file)
+
+        # Backup should be similar size to original (allowing for minor differences)
+        assert abs(backup_size - original_size) < 100  # Within 100 bytes
+
+    def test_backup_file_sorting(self):
+        """Test that backup files are sorted by creation time."""
+        # Create backups with small delays
+        import time
+        backup1 = self.auto_save.create_backup("first")
+        time.sleep(0.01)
+        backup2 = self.auto_save.create_backup("second")
+        time.sleep(0.01)
+        backup3 = self.auto_save.create_backup("third")
+
+        backup_files = self.auto_save.get_backup_files()
+
+        # Files should be sorted with newest first
+        assert len(backup_files) >= 3
+
+        # Check that the files are in the list (order might vary based on filesystem)
+        backup_names = [os.path.basename(f) for f in backup_files]
+        assert any("first" in name for name in backup_names)
+        assert any("second" in name for name in backup_names)
+        assert any("third" in name for name in backup_names)
diff --git a/tests/test_error_handler.py b/tests/test_error_handler.py
new file mode 100644
index 0000000..d0bc256
--- /dev/null
+++ b/tests/test_error_handler.py
@@ -0,0 +1,169 @@
+"""Tests for error handling system."""
+
+import pytest
+from unittest.mock import MagicMock, patch
+import time
+import logging
+
+from src.error_handler import ErrorHandler, OperationTimer
+
+
+class TestErrorHandler:
+    """Test cases for ErrorHandler class."""
+
+    def setup_method(self):
+        """Set up test fixtures before each test method."""
+        self.mock_logger = MagicMock()
+        self.mock_ui_manager = MagicMock()
+        self.error_handler = ErrorHandler(self.mock_logger, self.mock_ui_manager)
+
+    def test_error_handler_initialization(self):
+        """Test ErrorHandler initializes correctly."""
+        assert self.error_handler.logger == self.mock_logger
+        assert self.error_handler.ui_manager == self.mock_ui_manager
+        assert self.error_handler.error_counts == {}
+        assert self.error_handler.last_error_time == {}
+
+    def test_handle_error_basic(self):
+        """Test basic error handling."""
+        error = ValueError("Test error")
+        self.error_handler.handle_error(error, "Test context")
+
+        # Verify logging
+        self.mock_logger.error.assert_called_once()
+
+        # Verify UI feedback if show_dialog is True
+        self.mock_ui_manager.show_error_dialog.assert_called_once()
+
+    def test_handle_error_without_dialog(self):
+        """Test error handling without showing dialog."""
+        error = ValueError("Test error")
+        self.error_handler.handle_error(error, "Test context", show_dialog=False)
+
+        # Verify logging
+        self.mock_logger.error.assert_called_once()
+
+        # Verify no UI dialog
+        self.mock_ui_manager.show_error_dialog.assert_not_called()
+
+    def test_handle_error_with_custom_message(self):
+        """Test error handling with custom user message."""
+        error = ValueError("Test error")
+        custom_message = "Custom error message"
+        self.error_handler.handle_error(error, "Test context", user_message=custom_message)
+
+        # Verify custom message is used
+        self.mock_ui_manager.show_error_dialog.assert_called_once()
+        args = self.mock_ui_manager.show_error_dialog.call_args[0]
+        assert custom_message in args[0]
+
+    def test_error_frequency_tracking(self):
+        """Test that error frequency is tracked correctly."""
+        error = ValueError("Test error")
+        context = "Test context"
+
+        # Handle same error multiple times
+        self.error_handler.handle_error(error, context)
+        self.error_handler.handle_error(error, context)
+        self.error_handler.handle_error(error, context)
+
+        # Check error counting
+        error_key = f"{type(error).__name__}:{context}"
+        assert self.error_handler.error_counts[error_key] == 3
+
+    def test_log_performance_warning(self):
+        """Test performance warning logging."""
+        operation = "test_operation"
+        duration = 5.0
+
+        self.error_handler.log_performance_warning(operation, duration)
+
+        # Verify warning is logged
+        self.mock_logger.warning.assert_called_once()
+        log_call = self.mock_logger.warning.call_args[0][0]
+        assert "Performance warning" in log_call
+        assert operation in log_call
+        assert str(duration) in log_call
+
+    def test_operation_timer_context_manager(self):
+        """Test operation timer context manager."""
+        timer = OperationTimer(self.error_handler, "test_operation")
+
+        with timer:
+            time.sleep(0.1)  # Short sleep to simulate work
+
+        # With default threshold, this should not trigger a warning
+        self.mock_logger.warning.assert_not_called()
+
+    def test_operation_timer_with_warning(self):
+        """Test operation timer triggers warning for slow operations."""
+        # Use very low threshold to trigger warning
+        timer = OperationTimer(self.error_handler, "test_operation", warning_threshold=0.01)
+
+        with timer:
+            time.sleep(0.1)  # Sleep longer than threshold
+
+        # Should trigger performance warning
+        self.mock_logger.warning.assert_called_once()
+
+    def test_multiple_error_types(self):
+        """Test handling different types of errors."""
+        errors = [
+            ValueError("Value error"),
+            FileNotFoundError("File not found"),
+            RuntimeError("Runtime error"),
+        ]
+
+        for error in errors:
+            self.error_handler.handle_error(error, "Test context")
+
+        # Verify all errors were logged
+        assert self.mock_logger.error.call_count == len(errors)
+        assert self.mock_ui_manager.show_error_dialog.call_count == len(errors)
+
+
+class TestErrorHandlerEdgeCases:
+    """Test edge cases and error conditions."""
+
+    def setup_method(self):
+        """Set up test fixtures."""
+        self.mock_logger = MagicMock()
+        self.error_handler = ErrorHandler(self.mock_logger)  # No UI manager
+
+    def test_error_handler_without_ui_manager(self):
+        """Test error handling when UI manager is not available."""
+        error = ValueError("Test error")
+
+        # Should not raise exception even without UI manager
+        self.error_handler.handle_error(error, "Test context")
+
+        # Should still log the error
+        self.mock_logger.error.assert_called_once()
+
+    def test_handle_none_error(self):
+        """Test handling when error is None."""
+        # Should handle gracefully
+        self.error_handler.handle_error(None, "Test context")
+
+        # Should still attempt to log
+        self.mock_logger.error.assert_called_once()
+
+    def test_operation_timer_without_error_handler(self):
+        """Test operation timer with None error handler."""
+        timer = OperationTimer(None, "test_operation")
+
+        # Should not raise exception
+        with timer:
+            time.sleep(0.1)
+
+    def test_empty_context(self):
+        """Test error handling with empty context."""
+        error = ValueError("Test error")
+        self.error_handler.handle_error(error, "")
+
+        # Should still work with empty context
+        self.mock_logger.error.assert_called_once()
+
+
+if __name__ == "__main__":
+    pytest.main([__file__])
diff --git a/tests/test_input_validator.py b/tests/test_input_validator.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/test_integration.py b/tests/test_integration.py
index c72aeae..58d67cb 100644
--- a/tests/test_integration.py
+++ b/tests/test_integration.py
@@ -11,16 +11,21 @@ from pathlib import Path
 from unittest.mock import Mock, patch, MagicMock
 import pytest
 import pandas as pd
+import time
 
 # Add src to path
 sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
 
 from data_manager import DataManager
 from export_manager import ExportManager
-from init import logger
+from input_validator import InputValidator
+from error_handler import ErrorHandler
+from auto_save import AutoSaveManager
+from search_filter import DataFilter, QuickFilters, SearchHistory
 from medicine_manager import MedicineManager
 from pathology_manager import PathologyManager
 from theme_manager import ThemeManager
+from init import logger
 
 
 class TestIntegrationSuite:
@@ -339,3 +344,341 @@ class TestSystemHealthChecks:
 
         # These should not raise exceptions
         assert True, "Logging system working correctly"
+
+
+class TestNewFeaturesIntegration:
+    """Integration tests for new features added to TheChart."""
+
+    @pytest.fixture(autouse=True)
+    def setup_new_features_test(self):
+        """Set up test environment for new features."""
+        self.temp_dir = tempfile.mkdtemp()
+        self.test_csv = os.path.join(self.temp_dir, "test_data.csv")
+        self.backup_dir = os.path.join(self.temp_dir, "backups")
+
+        # Create sample data
+        sample_data = pd.DataFrame({
+            'date': ['01/01/2024', '01/15/2024', '02/01/2024'],
+            'note': ['First entry', 'Second entry', 'Third entry'],
+            'medicine1': [1, 0, 1],  # 1 = taken, 0 = not taken
+            'pathology1': [3, 7, 9]
+        })
+        sample_data.to_csv(self.test_csv, index=False)
+
+        # Initialize managers
+        self.medicine_manager = MedicineManager(logger=logger)
+        self.pathology_manager = PathologyManager(logger=logger)
+
+        yield
+
+        # Cleanup
+        import shutil
+        if os.path.exists(self.temp_dir):
+            shutil.rmtree(self.temp_dir)
+
+    def test_input_validation_integration(self):
+        """Test input validation system integration."""
+        print("Testing input validation integration...")
+
+        # Test comprehensive validation workflow
+        test_cases = [
+            # (field_type, value, expected_valid)
+            ("date", "01/15/2024", True),
+            ("date", "invalid-date", False),
+            ("pathology_score", "5", True),
+            ("pathology_score", "15", False),
+            ("note", "Valid note", True),
+            ("note", "A" * 1001, False),  # Too long
+            ("filename", "data.csv", True),
+            ("filename", "A" * 150, False),  # Too long filename
+        ]
+
+        for field_type, value, expected_valid in test_cases:
+            if field_type == "date":
+                is_valid, _, _ = InputValidator.validate_date(value)
+            elif field_type == "pathology_score":
+                is_valid, _, _ = InputValidator.validate_pathology_score(value)
+            elif field_type == "note":
+                is_valid, _, _ = InputValidator.validate_note(value)
+            elif field_type == "filename":
+                is_valid, _, _ = InputValidator.validate_filename(value)
+
+            assert is_valid == expected_valid, \
+                f"Validation failed for {field_type}='{value}': expected {expected_valid}, got {is_valid}"
+
+    def test_error_handling_integration(self):
+        """Test error handling system integration."""
+        print("Testing error handling integration...")
+
+        # Create a logger for testing
+        import logging
+        test_logger = logging.getLogger("test")
+        mock_ui_manager = MagicMock()
+        error_handler = ErrorHandler(logger=test_logger, ui_manager=mock_ui_manager)
+
+        # Test different error types
+        error_scenarios = [
+            (ValueError("Invalid input"), "Input validation", "Validation failed"),
+            (FileNotFoundError("File not found"), "File operation", "File operation failed"),
+            (RuntimeError("Unknown error"), "Runtime operation", "Unexpected error")
+        ]
+
+        for error, context, user_message in error_scenarios:
+            # Test basic error handling
+            error_handler.handle_error(error, context, user_message, show_dialog=False)
+
+            # Verify the UI manager was called to update status
+            assert mock_ui_manager.update_status.called, f"Status update not called for {context}"
+
+        # Test validation error handling
+        error_handler.handle_validation_error("test_field", "Invalid value", "Use a valid value")
+        assert mock_ui_manager.update_status.called, "Validation error handling failed"
+
+        # Test file error handling
+        error_handler.handle_file_error("read", "/test/file.csv", FileNotFoundError("File missing"))
+        assert mock_ui_manager.update_status.called, "File error handling failed"
+
+    def test_auto_save_integration(self):
+        """Test auto-save system integration."""
+        print("Testing auto-save integration...")
+
+        mock_save_callback = MagicMock()
+
+        auto_save = AutoSaveManager(
+            save_callback=mock_save_callback,
+            interval_minutes=0.01,  # Very short for testing
+        )
+
+        try:
+            # Test enabling auto-save
+            auto_save.enable_auto_save()
+            assert auto_save._auto_save_enabled, "Auto-save should be enabled"
+
+            # Test data modification tracking
+            auto_save.mark_data_modified()
+            assert auto_save._data_modified, "Data should be marked as modified"
+
+            # Test force save
+            auto_save.force_save()
+            assert mock_save_callback.called, "Save callback should be called on force save"
+
+            # Test save with modifications
+            auto_save.mark_data_modified()
+            auto_save.force_save()  # Call force_save again
+            assert mock_save_callback.call_count >= 2, "Save should be called when data is modified"
+
+            # Test disabling auto-save
+            auto_save.disable_auto_save()
+            assert not auto_save._auto_save_enabled, "Auto-save should be disabled"
+
+        finally:
+            auto_save.disable_auto_save()
+
+        print("Auto-save integration test passed!")
+
+    def test_search_filter_integration(self):
+        """Test search and filter system integration."""
+        print("Testing search and filter integration...")
+
+        # Load test data
+        test_data = pd.read_csv(self.test_csv)
+
+        data_filter = DataFilter()
+
+        # Test text search
+        data_filter.set_search_term("Second")
+        filtered_data = data_filter.apply_filters(test_data)
+        assert len(filtered_data) == 1, "Text search failed"
+        assert "Second entry" in filtered_data['note'].values
+
+        # Test date range filter
+        data_filter.clear_all_filters()
+        data_filter.set_date_range_filter("01/01/2024", "01/31/2024")
+        filtered_data = data_filter.apply_filters(test_data)
+        assert len(filtered_data) == 2, "Date range filter failed"
+
+        # Test medicine filter
+        data_filter.clear_all_filters()
+        data_filter.set_medicine_filter("medicine1", True)  # Taken
+        filtered_data = data_filter.apply_filters(test_data)
+        assert len(filtered_data) == 2, "Medicine filter (taken) failed"
+
+        data_filter.set_medicine_filter("medicine1", False)  # Not taken
+        filtered_data = data_filter.apply_filters(test_data)
+        assert len(filtered_data) == 1, "Medicine filter (not taken) failed"
+
+        # Test pathology range filter
+        data_filter.clear_all_filters()
+        data_filter.set_pathology_range_filter("pathology1", 5, 10)
+        filtered_data = data_filter.apply_filters(test_data)
+        assert len(filtered_data) == 2, "Pathology range filter failed"
+
+        # Test combined filters
+        data_filter.clear_all_filters()
+        data_filter.set_search_term("entry")
+        data_filter.set_pathology_range_filter("pathology1", 7, 10)
+        filtered_data = data_filter.apply_filters(test_data)
+        assert len(filtered_data) == 2, "Combined filters failed"
+
+        # Test quick filters
+        QuickFilters.last_week(data_filter)
+        assert "date_range" in data_filter.active_filters, "Quick filter (last week) failed"
+
+        QuickFilters.last_month(data_filter)
+        assert "date_range" in data_filter.active_filters, "Quick filter (last month) failed"
+
+        pathology_keys = self.pathology_manager.get_pathology_keys()
+        if pathology_keys:
+            QuickFilters.high_symptoms(data_filter, pathology_keys)
+            assert "pathologies" in data_filter.active_filters, "Quick filter (high symptoms) failed"
+
+    def test_search_history_integration(self):
+        """Test search history functionality."""
+        print("Testing search history integration...")
+
+        search_history = SearchHistory()
+
+        # Test adding searches
+        test_searches = ["symptom search", "medication query", "date range"]
+        for search in test_searches:
+            search_history.add_search(search)
+
+        history = search_history.get_history()
+        assert len(history) >= len(test_searches), "Search history not recording properly"
+
+        # Test search suggestions
+        suggestions = search_history.get_suggestions("med")
+        medication_suggestions = [s for s in suggestions if "med" in s.lower()]
+        assert len(medication_suggestions) >= 0, "Search suggestions not working"
+
+    def test_complete_workflow_integration(self):
+        """Test complete workflow with all new features."""
+        print("Testing complete workflow integration...")
+
+        # Initialize all systems
+        mock_save_callback = MagicMock()
+        auto_save = AutoSaveManager(
+            save_callback=mock_save_callback,
+            interval_minutes=5
+        )
+        data_filter = DataFilter()
+
+        try:
+            # Step 1: Enable auto-save
+            auto_save.enable_auto_save()
+
+            # Step 2: Validate new data entry
+            new_date = "01/15/2024"
+            new_note = "Workflow test entry"
+
+            date_valid, date_msg, _ = InputValidator.validate_date(new_date)
+            note_valid, note_msg, _ = InputValidator.validate_note(new_note)
+
+            assert date_valid, f"Date validation failed: {date_msg}"
+            assert note_valid, f"Note validation failed: {note_msg}"
+
+            score_valid, score_msg, _ = InputValidator.validate_pathology_score("6")
+            assert score_valid, f"Score validation failed: {score_msg}"
+
+            # Step 3: Add validated data to file
+            original_data = pd.read_csv(self.test_csv)
+            new_row = pd.DataFrame({
+                'date': [new_date],
+                'note': [new_note],
+                'medicine1': [0],
+                'pathology1': [6]
+            })
+            updated_data = pd.concat([original_data, new_row], ignore_index=True)
+            updated_data.to_csv(self.test_csv, index=False)
+
+            # Step 4: Mark data as modified for auto-save
+            auto_save.mark_data_modified()
+            auto_save.force_save()
+            assert mock_save_callback.called, "Auto-save should trigger save callback"
+
+            # Step 5: Test filtering on updated data
+            data_filter.set_search_term("Workflow")
+            filtered_data = data_filter.apply_filters(updated_data)
+            assert len(filtered_data) == 1, "Search filter failed on updated data"
+            assert any("Workflow" in note for note in filtered_data['note'].values)
+
+            # Step 6: Test date range filter
+            data_filter.clear_all_filters()
+            data_filter.set_date_range_filter("01/14/2024", "01/16/2024")  # Include both entries on 01/15
+            filtered_data = data_filter.apply_filters(updated_data)
+            assert len(filtered_data) == 2, "Date filter failed on new entry"
+
+            # Step 7: Test error handling with invalid operation
+            try:
+                # Simulate file operation error
+                raise FileNotFoundError("Simulated file error")
+            except FileNotFoundError as e:
+                import logging
+                test_logger = logging.getLogger("test")
+                mock_ui_manager = MagicMock()
+                error_handler = ErrorHandler(logger=test_logger, ui_manager=mock_ui_manager)
+                error_handler.handle_error(e, "Test error handling", "Simulated error", show_dialog=False)
+
+                # Verify error was handled
+                assert mock_ui_manager.update_status.called, "Error handling should update status"
+
+            # Step 8: Verify auto-save functionality
+            assert auto_save._auto_save_enabled, "Auto-save should be enabled"
+            auto_save.disable_auto_save()
+            assert not auto_save._auto_save_enabled, "Auto-save should be disabled"
+
+            print("Complete workflow integration test passed!")
+
+        finally:
+            auto_save.disable_auto_save()
+
+    def test_performance_under_load(self):
+        """Test system performance with larger datasets."""
+        print("Testing performance under load...")
+
+        # Create larger dataset
+        large_data = []
+        for i in range(100):
+            large_data.append({
+                'date': f"01/{(i % 28) + 1:02d}/2024",
+                'note': f"Entry number {i}",
+                'medicine1': 1 if i % 2 == 0 else 0,
+                'pathology1': (i % 10) + 1
+            })
+
+        large_df = pd.DataFrame(large_data)
+        large_csv = os.path.join(self.temp_dir, "large_data.csv")
+        large_df.to_csv(large_csv, index=False)
+
+        # Test filtering performance
+        data_filter = DataFilter()
+
+        start_time = time.time()
+        data_filter.set_search_term("Entry")
+        filtered_data = data_filter.apply_filters(large_df)
+        search_time = time.time() - start_time
+
+        assert len(filtered_data) == 100, "Search filter failed on large dataset"
+        assert search_time < 1.0, f"Search took too long: {search_time:.2f}s"
+
+        # Test auto-save performance
+        mock_save_callback = MagicMock()
+        auto_save = AutoSaveManager(
+            save_callback=mock_save_callback,
+            interval_minutes=5
+        )
+
+        try:
+            start_time = time.time()
+            auto_save.enable_auto_save()
+            auto_save.mark_data_modified()
+            auto_save.force_save()
+            save_time = time.time() - start_time
+
+            assert mock_save_callback.called, "Save callback should be called"
+            assert save_time < 2.0, f"Save took too long: {save_time:.2f}s"
+
+        finally:
+            auto_save.disable_auto_save()
+
+        print(f"Performance test completed: Search={search_time:.3f}s, Save={save_time:.3f}s")
diff --git a/tests/test_search_filter.py b/tests/test_search_filter.py
new file mode 100644
index 0000000..8c45a7a
--- /dev/null
+++ b/tests/test_search_filter.py
@@ -0,0 +1,353 @@
+"""Tests for search and filter system."""
+
+import pytest
+from datetime import datetime, timedelta
+import pandas as pd
+from unittest.mock import MagicMock
+
+from src.search_filter import DataFilter, QuickFilters, SearchHistory
+
+
+class TestDataFilter:
+    """Test cases for DataFilter class."""
+
+    def setup_method(self):
+        """Set up test fixtures."""
+        # Create sample data for testing
+        self.sample_data = pd.DataFrame({
+            'Date': ['2024-01-01', '2024-01-15', '2024-02-01', '2024-02-15'],
+            'Notes': ['First entry', 'Second entry', 'Third entry', 'Fourth entry'],
+            'medicine1': ['08:00:1', '', '12:00:2', '09:00:1|21:00:1'],
+            'medicine2': ['', '10:00:1', '', '14:00:0.5'],
+            'pathology1': [3, 7, 5, 9],
+            'pathology2': [2, 8, 4, 6]
+        })
+
+        self.data_filter = DataFilter()
+
+    def test_initialization(self):
+        """Test DataFilter initialization."""
+        assert len(self.data_filter.active_filters) == 0
+        assert self.data_filter.search_term == ""
+
+    def test_set_search_term(self):
+        """Test setting search term."""
+        self.data_filter.set_search_term("test search")
+        assert self.data_filter.search_term == "test search"
+
+        # Clear search term
+        self.data_filter.set_search_term("")
+        assert self.data_filter.search_term == ""
+
+    def test_text_search_in_notes(self):
+        """Test text search in notes field."""
+        self.data_filter.set_search_term("Second")
+        filtered_data = self.data_filter.apply_filters(self.sample_data)
+
+        assert len(filtered_data) == 1
+        assert "Second entry" in filtered_data['Notes'].values
+
+    def test_text_search_in_dates(self):
+        """Test text search in dates."""
+        self.data_filter.set_search_term("2024-02")
+        filtered_data = self.data_filter.apply_filters(self.sample_data)
+
+        assert len(filtered_data) == 2
+        assert all("2024-02" in date for date in filtered_data['Date'].values)
+
+    def test_text_search_case_insensitive(self):
+        """Test that text search is case insensitive."""
+        self.data_filter.set_search_term("FIRST")
+        filtered_data = self.data_filter.apply_filters(self.sample_data)
+
+        assert len(filtered_data) == 1
+        assert "First entry" in filtered_data['Notes'].values
+
+    def test_date_range_filter(self):
+        """Test date range filtering."""
+        self.data_filter.set_date_range_filter("2024-01-10", "2024-02-10")
+        filtered_data = self.data_filter.apply_filters(self.sample_data)
+
+        assert len(filtered_data) == 2
+        dates = pd.to_datetime(filtered_data['Date'])
+        assert all(pd.to_datetime("2024-01-10") <= date <= pd.to_datetime("2024-02-10") for date in dates)
+
+    def test_date_range_filter_start_only(self):
+        """Test date range filter with only start date."""
+        self.data_filter.set_date_range_filter("2024-02-01", None)
+        filtered_data = self.data_filter.apply_filters(self.sample_data)
+
+        assert len(filtered_data) == 2
+        dates = pd.to_datetime(filtered_data['Date'])
+        assert all(date >= pd.to_datetime("2024-02-01") for date in dates)
+
+    def test_date_range_filter_end_only(self):
+        """Test date range filter with only end date."""
+        self.data_filter.set_date_range_filter(None, "2024-01-31")
+        filtered_data = self.data_filter.apply_filters(self.sample_data)
+
+        assert len(filtered_data) == 2
+        dates = pd.to_datetime(filtered_data['Date'])
+        assert all(date <= pd.to_datetime("2024-01-31") for date in dates)
+
+    def test_medicine_filter_taken(self):
+        """Test medicine filter for taken medicines."""
+        self.data_filter.set_medicine_filter("medicine1", True)
+        filtered_data = self.data_filter.apply_filters(self.sample_data)
+
+        # Should return rows where medicine1 has a non-empty value
+        assert len(filtered_data) == 3
+        assert all(val != '' for val in filtered_data['medicine1'].values)
+
+    def test_medicine_filter_not_taken(self):
+        """Test medicine filter for not taken medicines."""
+        self.data_filter.set_medicine_filter("medicine1", False)
+        filtered_data = self.data_filter.apply_filters(self.sample_data)
+
+        # Should return rows where medicine1 is empty
+        assert len(filtered_data) == 1
+        assert filtered_data['medicine1'].iloc[0] == ''
+
+    def test_pathology_range_filter(self):
+        """Test pathology score range filtering."""
+        self.data_filter.set_pathology_range_filter("pathology1", 5, 8)
+        filtered_data = self.data_filter.apply_filters(self.sample_data)
+
+        assert len(filtered_data) == 2
+        scores = filtered_data['pathology1'].values
+        assert all(5 <= score <= 8 for score in scores)
+
+    def test_pathology_range_filter_min_only(self):
+        """Test pathology filter with only minimum value."""
+        self.data_filter.set_pathology_range_filter("pathology1", 6, None)
+        filtered_data = self.data_filter.apply_filters(self.sample_data)
+
+        assert len(filtered_data) == 2
+        scores = filtered_data['pathology1'].values
+        assert all(score >= 6 for score in scores)
+
+    def test_pathology_range_filter_max_only(self):
+        """Test pathology filter with only maximum value."""
+        self.data_filter.set_pathology_range_filter("pathology1", None, 5)
+        filtered_data = self.data_filter.apply_filters(self.sample_data)
+
+        assert len(filtered_data) == 2
+        scores = filtered_data['pathology1'].values
+        assert all(score <= 5 for score in scores)
+
+    def test_combined_filters(self):
+        """Test combining multiple filters."""
+        self.data_filter.set_search_term("entry")
+        self.data_filter.set_date_range_filter("2024-01-01", "2024-01-31")
+        self.data_filter.set_medicine_filter("medicine1", True)
+
+        filtered_data = self.data_filter.apply_filters(self.sample_data)
+
+        # Should satisfy all conditions
+        assert len(filtered_data) == 1
+        assert "entry" in filtered_data['Notes'].iloc[0]
+        assert filtered_data['Date'].iloc[0].startswith("2024-01")
+        assert filtered_data['medicine1'].iloc[0] != ''
+
+    def test_clear_filter(self):
+        """Test clearing specific filter types."""
+        # Set multiple filters
+        self.data_filter.set_search_term("test")
+        self.data_filter.set_date_range_filter("2024-01-01", "2024-12-31")
+        self.data_filter.set_medicine_filter("medicine1", True)
+
+        # Clear date range filter
+        self.data_filter.clear_filter("date_range")
+
+        assert "date_range" not in self.data_filter.active_filters
+        assert self.data_filter.search_term == "test"  # Other filters remain
+
+    def test_clear_all_filters(self):
+        """Test clearing all filters."""
+        # Set multiple filters
+        self.data_filter.set_search_term("test")
+        self.data_filter.set_date_range_filter("2024-01-01", "2024-12-31")
+        self.data_filter.set_medicine_filter("medicine1", True)
+
+        # Clear all filters
+        self.data_filter.clear_all_filters()
+
+        assert len(self.data_filter.active_filters) == 0
+        assert self.data_filter.search_term == ""
+
+    def test_get_filter_summary(self):
+        """Test getting filter summary."""
+        # No filters
+        summary = self.data_filter.get_filter_summary()
+        assert not summary["has_filters"]
+        assert summary["search_term"] == ""
+        assert len(summary["filters"]) == 0
+
+        # With filters
+        self.data_filter.set_search_term("test")
+        self.data_filter.set_date_range_filter("2024-01-01", "2024-12-31")
+
+        summary = self.data_filter.get_filter_summary()
+        assert summary["has_filters"]
+        assert summary["search_term"] == "test"
+        assert "date_range" in summary["filters"]
+
+    def test_no_filters_returns_original_data(self):
+        """Test that no filters returns original data unchanged."""
+        filtered_data = self.data_filter.apply_filters(self.sample_data)
+        pd.testing.assert_frame_equal(filtered_data, self.sample_data)
+
+    def test_filter_with_empty_data(self):
+        """Test filtering with empty DataFrame."""
+        empty_data = pd.DataFrame()
+        self.data_filter.set_search_term("test")
+
+        filtered_data = self.data_filter.apply_filters(empty_data)
+        assert len(filtered_data) == 0
+
+    def test_invalid_date_handling(self):
+        """Test handling of invalid dates in data."""
+        invalid_data = self.sample_data.copy()
+        invalid_data.loc[0, 'Date'] = 'invalid-date'
+
+        self.data_filter.set_date_range_filter("2024-01-01", "2024-12-31")
+
+        # Should handle invalid dates gracefully
+        filtered_data = self.data_filter.apply_filters(invalid_data)
+        assert len(filtered_data) >= 0  # Should not crash
+
+
+class TestQuickFilters:
+    """Test cases for QuickFilters class."""
+
+    def setup_method(self):
+        """Set up test fixtures."""
+        self.data_filter = DataFilter()
+
+    def test_last_week_filter(self):
+        """Test last week quick filter."""
+        QuickFilters.last_week(self.data_filter)
+
+        assert "date_range" in self.data_filter.active_filters
+        date_filter = self.data_filter.active_filters["date_range"]
+
+        # Should have end date as today and start date 7 days ago
+        end_date = pd.to_datetime(date_filter["end"])
+        start_date = pd.to_datetime(date_filter["start"])
+
+        assert (end_date - start_date).days == 6  # 7 days inclusive
+
+    def test_last_month_filter(self):
+        """Test last month quick filter."""
+        QuickFilters.last_month(self.data_filter)
+
+        assert "date_range" in self.data_filter.active_filters
+        date_filter = self.data_filter.active_filters["date_range"]
+
+        # Should have end date as today and start date 30 days ago
+        end_date = pd.to_datetime(date_filter["end"])
+        start_date = pd.to_datetime(date_filter["start"])
+
+        assert (end_date - start_date).days == 29  # 30 days inclusive
+
+    def test_this_month_filter(self):
+        """Test this month quick filter."""
+        QuickFilters.this_month(self.data_filter)
+
+        assert "date_range" in self.data_filter.active_filters
+        date_filter = self.data_filter.active_filters["date_range"]
+
+        # Should start from first day of current month
+        start_date = pd.to_datetime(date_filter["start"])
+        today = pd.to_datetime("today")
+
+        assert start_date.day == 1
+        assert start_date.month == today.month
+        assert start_date.year == today.year
+
+    def test_high_symptoms_filter(self):
+        """Test high symptoms quick filter."""
+        pathology_keys = ["pathology1", "pathology2", "pathology3"]
+
+        QuickFilters.high_symptoms(self.data_filter, pathology_keys)
+
+        assert "pathologies" in self.data_filter.active_filters
+        pathology_filters = self.data_filter.active_filters["pathologies"]
+
+        # Should set minimum score of 8 for all pathologies
+        for key in pathology_keys:
+            assert key in pathology_filters
+            assert pathology_filters[key]["min"] == 8
+            assert pathology_filters[key]["max"] is None
+
+
+class TestSearchHistory:
+    """Test cases for SearchHistory class."""
+
+    def setup_method(self):
+        """Set up test fixtures."""
+        self.search_history = SearchHistory()
+
+    def test_initialization(self):
+        """Test SearchHistory initialization."""
+        assert len(self.search_history.get_history()) == 0
+
+    def test_add_search(self):
+        """Test adding search terms."""
+        self.search_history.add_search("test search")
+
+        history = self.search_history.get_history()
+        assert len(history) == 1
+        assert "test search" in history
+
+    def test_duplicate_search_handling(self):
+        """Test that duplicate searches are handled appropriately."""
+        self.search_history.add_search("test search")
+        self.search_history.add_search("test search")
+
+        history = self.search_history.get_history()
+        # Implementation may vary - could deduplicate or keep most recent
+        assert "test search" in history
+
+    def test_empty_search_handling(self):
+        """Test handling of empty search terms."""
+        self.search_history.add_search("")
+        self.search_history.add_search("   ")  # Whitespace only
+
+        history = self.search_history.get_history()
+        # Empty/whitespace searches should be ignored or handled appropriately
+        assert len([s for s in history if s.strip()]) == 0
+
+    def test_search_history_limit(self):
+        """Test search history size limit."""
+        # Add many searches
+        for i in range(20):
+            self.search_history.add_search(f"search {i}")
+
+        history = self.search_history.get_history()
+        # Should have reasonable limit (implementation dependent)
+        assert len(history) <= 15  # Assuming max 15 items
+
+    def test_get_suggestions(self):
+        """Test getting search suggestions."""
+        # Add some searches
+        searches = ["apple pie", "apple tart", "banana bread", "chocolate cake"]
+        for search in searches:
+            self.search_history.add_search(search)
+
+        # Test prefix matching
+        suggestions = self.search_history.get_suggestions("app")
+        apple_suggestions = [s for s in suggestions if "apple" in s.lower()]
+        assert len(apple_suggestions) >= 1
+
+    def test_clear_history(self):
+        """Test clearing search history."""
+        # Add some searches
+        self.search_history.add_search("test1")
+        self.search_history.add_search("test2")
+
+        # Clear history
+        self.search_history.clear_history()
+
+        history = self.search_history.get_history()
+        assert len(history) == 0
diff --git a/tests/test_search_filter_ui.py b/tests/test_search_filter_ui.py
new file mode 100644
index 0000000..13a6322
--- /dev/null
+++ b/tests/test_search_filter_ui.py
@@ -0,0 +1,335 @@
+"""Tests for search and filter UI components."""
+
+import pytest
+import tkinter as tk
+from unittest.mock import MagicMock, patch
+from tkinter import ttk
+
+from src.search_filter_ui import SearchFilterWidget
+from src.search_filter import DataFilter
+
+
+class TestSearchFilterWidget:
+    """Test cases for SearchFilterWidget class."""
+
+    def setup_method(self):
+        """Set up test fixtures."""
+        # Create root window for testing
+        self.root = tk.Tk()
+        self.root.withdraw()  # Hide window during testing
+
+        # Mock managers and dependencies
+        self.mock_data_filter = MagicMock(spec=DataFilter)
+        self.mock_update_callback = MagicMock()
+        self.mock_medicine_manager = MagicMock()
+        self.mock_pathology_manager = MagicMock()
+
+        # Configure mock medicine manager
+        self.mock_medicine_manager.get_medicine_keys.return_value = ["med1", "med2"]
+        mock_medicine1 = MagicMock()
+        mock_medicine1.display_name = "Medicine 1"
+        mock_medicine2 = MagicMock()
+        mock_medicine2.display_name = "Medicine 2"
+        self.mock_medicine_manager.get_medicine.side_effect = lambda key: {
+            "med1": mock_medicine1,
+            "med2": mock_medicine2
+        }.get(key)
+
+        # Configure mock pathology manager
+        self.mock_pathology_manager.get_pathology_keys.return_value = ["path1", "path2"]
+        mock_pathology1 = MagicMock()
+        mock_pathology1.display_name = "Pathology 1"
+        mock_pathology2 = MagicMock()
+        mock_pathology2.display_name = "Pathology 2"
+        self.mock_pathology_manager.get_pathology.side_effect = lambda key: {
+            "path1": mock_pathology1,
+            "path2": mock_pathology2
+        }.get(key)
+
+        # Create main frame as parent
+        self.parent_frame = ttk.Frame(self.root)
+        self.parent_frame.pack(fill="both", expand=True)
+
+        # Create widget
+        self.search_widget = SearchFilterWidget(
+            parent=self.parent_frame,
+            data_filter=self.mock_data_filter,
+            update_callback=self.mock_update_callback,
+            medicine_manager=self.mock_medicine_manager,
+            pathology_manager=self.mock_pathology_manager
+        )
+
+    def teardown_method(self):
+        """Clean up test fixtures."""
+        if hasattr(self, 'search_widget'):
+            self.search_widget.hide()
+        if hasattr(self, 'root'):
+            self.root.destroy()
+
+    def test_initialization(self):
+        """Test SearchFilterWidget initialization."""
+        assert self.search_widget.parent == self.parent_frame
+        assert self.search_widget.data_filter == self.mock_data_filter
+        assert self.search_widget.update_callback == self.mock_update_callback
+        assert not self.search_widget.is_visible
+
+        # Check that UI variables are initialized
+        assert hasattr(self.search_widget, 'search_var')
+        assert hasattr(self.search_widget, 'start_date_var')
+        assert hasattr(self.search_widget, 'end_date_var')
+        assert hasattr(self.search_widget, 'medicine_vars')
+        assert hasattr(self.search_widget, 'pathology_min_vars')
+        assert hasattr(self.search_widget, 'pathology_max_vars')
+
+    def test_widget_creation(self):
+        """Test that widget components are created properly."""
+        widget = self.search_widget.get_widget()
+        assert isinstance(widget, ttk.LabelFrame)
+        assert widget.winfo_exists()
+
+    def test_medicine_variables_creation(self):
+        """Test that medicine filter variables are created."""
+        assert "med1" in self.search_widget.medicine_vars
+        assert "med2" in self.search_widget.medicine_vars
+
+        # Test default values
+        assert self.search_widget.medicine_vars["med1"].get() == "any"
+        assert self.search_widget.medicine_vars["med2"].get() == "any"
+
+    def test_pathology_variables_creation(self):
+        """Test that pathology filter variables are created."""
+        assert "path1" in self.search_widget.pathology_min_vars
+        assert "path1" in self.search_widget.pathology_max_vars
+        assert "path2" in self.search_widget.pathology_min_vars
+        assert "path2" in self.search_widget.pathology_max_vars
+
+    def test_show_hide_functionality(self):
+        """Test show and hide functionality."""
+        # Initially hidden
+        assert not self.search_widget.is_visible
+
+        # Show widget
+        self.search_widget.show()
+        assert self.search_widget.is_visible
+
+        # Hide widget
+        self.search_widget.hide()
+        assert not self.search_widget.is_visible
+
+    def test_toggle_functionality(self):
+        """Test toggle functionality."""
+        # Initially hidden, toggle should show
+        initial_state = self.search_widget.is_visible
+        self.search_widget.toggle()
+        assert self.search_widget.is_visible != initial_state
+
+        # Toggle again should hide
+        self.search_widget.toggle()
+        assert self.search_widget.is_visible == initial_state
+
+    def test_search_change_callback(self):
+        """Test search term change callback."""
+        # Set search term
+        self.search_widget.search_var.set("test search")
+
+        # Should trigger update callback
+        self.root.update()  # Process events
+
+        # Verify data filter was updated
+        self.mock_data_filter.set_search_term.assert_called_with("test search")
+        self.mock_update_callback.assert_called()
+
+    def test_date_change_callback(self):
+        """Test date range change callback."""
+        # Set date range
+        self.search_widget.start_date_var.set("2024-01-01")
+        self.search_widget.end_date_var.set("2024-12-31")
+
+        # Process events
+        self.root.update()
+
+        # Verify data filter was updated
+        self.mock_data_filter.set_date_range_filter.assert_called()
+
+    def test_medicine_change_callback(self):
+        """Test medicine filter change callback."""
+        # Set medicine filter
+        self.search_widget.medicine_vars["med1"].set("taken")
+
+        # Process events
+        self.root.update()
+
+        # Verify data filter was updated
+        self.mock_data_filter.set_medicine_filter.assert_called()
+        self.mock_update_callback.assert_called()
+
+    def test_pathology_change_callback(self):
+        """Test pathology filter change callback."""
+        # Set pathology range
+        self.search_widget.pathology_min_vars["path1"].set("5")
+        self.search_widget.pathology_max_vars["path1"].set("9")
+
+        # Process events
+        self.root.update()
+
+        # Verify data filter was updated
+        self.mock_data_filter.set_pathology_range_filter.assert_called()
+
+    def test_clear_search_functionality(self):
+        """Test clear search functionality."""
+        # Set search term
+        self.search_widget.search_var.set("test search")
+
+        # Clear search
+        self.search_widget._clear_search()
+
+        assert self.search_widget.search_var.get() == ""
+
+    def test_clear_all_filters_functionality(self):
+        """Test clear all filters functionality."""
+        # Set various filters
+        self.search_widget.search_var.set("test")
+        self.search_widget.start_date_var.set("2024-01-01")
+        self.search_widget.medicine_vars["med1"].set("taken")
+        self.search_widget.pathology_min_vars["path1"].set("5")
+
+        # Clear all filters
+        self.search_widget._clear_all_filters()
+
+        # Verify all are cleared
+        assert self.search_widget.search_var.get() == ""
+        assert self.search_widget.start_date_var.get() == ""
+        assert self.search_widget.medicine_vars["med1"].get() == "any"
+        assert self.search_widget.pathology_min_vars["path1"].get() == ""
+
+        # Verify data filter was cleared
+        self.mock_data_filter.clear_all_filters.assert_called()
+
+    def test_quick_filter_buttons(self):
+        """Test quick filter button functionality."""
+        with patch('src.search_filter.QuickFilters') as mock_quick_filters:
+            # Test week filter
+            self.search_widget._filter_last_week()
+            mock_quick_filters.last_week.assert_called_with(self.mock_data_filter)
+
+            # Test month filter
+            self.search_widget._filter_last_month()
+            mock_quick_filters.last_month.assert_called_with(self.mock_data_filter)
+
+            # Test high symptoms filter
+            self.search_widget._filter_high_symptoms()
+            mock_quick_filters.high_symptoms.assert_called()
+
+    def test_apply_filters_functionality(self):
+        """Test manual apply filters functionality."""
+        # Set some filters
+        self.search_widget.search_var.set("test")
+        self.search_widget.start_date_var.set("2024-01-01")
+
+        # Apply filters manually
+        self.search_widget._apply_filters()
+
+        # Should have called various filter methods
+        self.mock_data_filter.set_search_term.assert_called()
+        self.mock_data_filter.set_date_range_filter.assert_called()
+
+    def test_status_update(self):
+        """Test status label update functionality."""
+        # Mock filter summary
+        mock_summary = {
+            "has_filters": True,
+            "search_term": "test",
+            "filters": {
+                "date_range": {"start": "2024-01-01", "end": "2024-12-31"},
+                "medicines": {"taken": ["med1"], "not_taken": []},
+                "pathologies": {"path1": {"min": 5, "max": 9}}
+            }
+        }
+
+        self.mock_data_filter.get_filter_summary.return_value = mock_summary
+
+        # Update status
+        self.search_widget._update_status()
+
+        # Check that status label was updated
+        status_text = self.search_widget.status_label.cget("text")
+        assert "Active filters" in status_text
+
+    def test_no_medicines_handling(self):
+        """Test handling when no medicines are configured."""
+        # Create widget with no medicines
+        self.mock_medicine_manager.get_medicine_keys.return_value = []
+
+        widget = SearchFilterWidget(
+            parent=self.parent_frame,
+            data_filter=self.mock_data_filter,
+            update_callback=self.mock_update_callback,
+            medicine_manager=self.mock_medicine_manager,
+            pathology_manager=self.mock_pathology_manager
+        )
+
+        assert len(widget.medicine_vars) == 0
+
+    def test_no_pathologies_handling(self):
+        """Test handling when no pathologies are configured."""
+        # Create widget with no pathologies
+        self.mock_pathology_manager.get_pathology_keys.return_value = []
+
+        widget = SearchFilterWidget(
+            parent=self.parent_frame,
+            data_filter=self.mock_data_filter,
+            update_callback=self.mock_update_callback,
+            medicine_manager=self.mock_medicine_manager,
+            pathology_manager=self.mock_pathology_manager
+        )
+
+        assert len(widget.pathology_min_vars) == 0
+        assert len(widget.pathology_max_vars) == 0
+
+    def test_horizontal_layout(self):
+        """Test that the horizontal layout is properly implemented."""
+        widget = self.search_widget.get_widget()
+
+        # Widget should exist and be properly configured
+        assert widget.winfo_exists()
+
+        # The main frame should be a LabelFrame with "Search & Filter" text
+        assert isinstance(widget, ttk.LabelFrame)
+
+    def test_grid_configuration(self):
+        """Test grid configuration for parent row management."""
+        # Mock parent with grid_rowconfigure method
+        mock_parent = MagicMock()
+        mock_parent.grid_rowconfigure = MagicMock()
+
+        widget = SearchFilterWidget(
+            parent=mock_parent,
+            data_filter=self.mock_data_filter,
+            update_callback=self.mock_update_callback,
+            medicine_manager=self.mock_medicine_manager,
+            pathology_manager=self.mock_pathology_manager
+        )
+
+        # Show widget
+        widget.show()
+
+        # Should configure parent grid row
+        mock_parent.grid_rowconfigure.assert_called_with(1, minsize=150, weight=0)
+
+        # Hide widget
+        widget.hide()
+
+        # Should reset parent grid row
+        mock_parent.grid_rowconfigure.assert_called_with(1, minsize=0, weight=0)
+
+    def test_widget_responsiveness(self):
+        """Test that widget responds to window resize."""
+        # This is a basic test - in a real scenario you'd test actual resize behavior
+        widget = self.search_widget.get_widget()
+
+        # Widget should be able to handle pack/grid configuration
+        assert widget.winfo_exists()
+
+        # Show and hide should work without errors
+        self.search_widget.show()
+        self.search_widget.hide()