diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
new file mode 100644
index 0000000..7a7e3f4
--- /dev/null
+++ b/.github/workflows/test.yml
@@ -0,0 +1,25 @@
+name: Tests
+on:
+  push:
+    branches: [main, master]
+  pull_request:
+    branches: [main, master]
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ['3.11', '3.12']
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install pytest
+          if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
+      - name: Run tests
+        run: python -m pytest tests/ -v
diff --git a/.gitignore b/.gitignore
index 7c8d622..dd30cf6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,14 @@
 ./__pycache__/
-./__pycache__
\ No newline at end of file
+./__pycache__
+# Auto-added by Marisol pipeline
+node_modules/
+*.pyc
+.pytest_cache/
+*.o
+*.so
+.env
+debug_*.py
+.cache/
+dist/
+build/
+*.egg-info/
diff --git a/__pycache__/dropbox.cpython-37.pyc b/__pycache__/dropbox.cpython-37.pyc
deleted file mode 100644
index e2df8a2..0000000
Binary files a/__pycache__/dropbox.cpython-37.pyc and /dev/null differ
diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 0000000..62c73b4
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,241 @@
+"""Auto-generated conftest.py -- mocks Raspberry Pi hardware modules.
+
+Provides:
+- 15+ RPi hardware modules pre-mocked (RPi.GPIO with realistic constants, guizero, etc.)
+- source_module fixture: loads repo .py files with while-True loops stripped via AST
+- All other module-level init code runs safely against mocks
+"""
+import sys
+import os
+import ast
+import types
+import glob as _glob
+from unittest.mock import MagicMock
+import pytest
+
+# --- Mock ALL RPi hardware modules ---
+_RPI_MODULES = [
+    'RPi', 'RPi.GPIO', 'spidev', 'smbus', 'smbus2',
+    'guizero', 'guizero.app', 'guizero.widgets',
+    'picamera', 'picamera2',
+    'gpiozero', 'gpiozero.pins', 'gpiozero.pins.mock',
+    'board', 'digitalio', 'busio', 'adafruit_dht',
+    'w1thermsensor', 'Adafruit_DHT',
+    'RPIO', 'pigpio', 'wiringpi',
+    'sense_hat', 'luma.core', 'luma.oled', 'luma.led_matrix',
+    'serial',
+]
+
+for _mod in _RPI_MODULES:
+    sys.modules[_mod] = MagicMock()
+
+# Import hook: auto-mock ANY unknown hardware module during source file loading
+# This catches custom libraries like mp2624, adafruit_* variants, etc.
+# Uses find_spec (Python 3.4+) since find_module is deprecated and ignored in Python 3.12
+import importlib.abc
+import importlib.machinery
+
+class _AutoMockFinder(importlib.abc.MetaPathFinder):
+    """Meta-path finder that auto-mocks missing modules instead of raising ImportError."""
+    _BUILTIN_SKIP = {
+        'os', 'sys', 'json', 'time', 'datetime', 'math', 're', 'pathlib',
+        'subprocess', 'shutil', 'collections', 'functools', 'itertools',
+        'logging', 'typing', 'dataclasses', 'enum', 'copy', 'io',
+        'threading', 'multiprocessing', 'socket', 'http', 'urllib',
+        'hashlib', 'base64', 'struct', 'array', 'configparser', 'argparse',
+        'unittest', 'pytest', 'glob', 'fnmatch', 'csv', 'string',
+    }
+    _active = False
+
+    def find_spec(self, name, path, target=None):
+        if not self._active:
+            return None
+        top = name.split('.')[0]
+        if top in self._BUILTIN_SKIP:
+            return None
+        if name in sys.modules:
+            return None
+        # Create a mock module and register it
+        mock = MagicMock()
+        mock.__name__ = name
+        mock.__spec__ = importlib.machinery.ModuleSpec(name, None)
+        sys.modules[name] = mock
+        return mock.__spec__
+
+_auto_mocker = _AutoMockFinder()
+sys.meta_path.insert(0, _auto_mocker)
+
+# Realistic RPi.GPIO constants
+_gpio = sys.modules['RPi.GPIO']
+_gpio.BCM = 11
+_gpio.BOARD = 10
+_gpio.OUT = 0
+_gpio.IN = 1
+_gpio.HIGH = 1
+_gpio.LOW = 0
+_gpio.PUD_UP = 22
+_gpio.PUD_DOWN = 21
+_gpio.RISING = 31
+_gpio.FALLING = 32
+_gpio.BOTH = 33
+
+# Make guizero App work as context manager
+_guizero = sys.modules['guizero']
+_guizero.App.return_value.__enter__ = MagicMock(return_value=MagicMock())
+_guizero.App.return_value.__exit__ = MagicMock(return_value=False)
+
+
+def _is_while_true(node):
+    """Check if an AST node is a while-True/while-1 loop."""
+    if not isinstance(node, ast.While):
+        return False
+    test = node.test
+    if isinstance(test, ast.Constant) and test.value in (True, 1):
+        return True
+    if isinstance(test, ast.NameConstant) and test.value is True:
+        return True
+    return False
+
+
+def _strip_while_true_from_body(body):
+    """Recursively strip while-True loops from AST node bodies."""
+    new_body = []
+    for node in body:
+        if _is_while_true(node):
+            continue
+        if isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef)):
+            node.body = _strip_while_true_from_body(node.body)
+        elif isinstance(node, ast.ClassDef):
+            node.body = _strip_while_true_from_body(node.body)
+        elif isinstance(node, ast.If):
+            node.body = _strip_while_true_from_body(node.body)
+            if node.orelse:
+                node.orelse = _strip_while_true_from_body(node.orelse)
+        elif isinstance(node, (ast.For, ast.AsyncFor, ast.While)):
+            node.body = _strip_while_true_from_body(node.body)
+        elif isinstance(node, (ast.With, ast.AsyncWith)):
+            node.body = _strip_while_true_from_body(node.body)
+        elif isinstance(node, ast.Try):
+            node.body = _strip_while_true_from_body(node.body)
+            for handler in node.handlers:
+                handler.body = _strip_while_true_from_body(handler.body)
+            if node.orelse:
+                node.orelse = _strip_while_true_from_body(node.orelse)
+            if node.finalbody:
+                node.finalbody = _strip_while_true_from_body(node.finalbody)
+        new_body.append(node)
+    return new_body
+
+
+def _strip_while_true(source_path):
+    """Recursively strip while-True loops from all nesting levels."""
+    with open(source_path) as f:
+        source = f.read()
+    try:
+        tree = ast.parse(source)
+        tree.body = _strip_while_true_from_body(tree.body)
+        ast.fix_missing_locations(tree)
+        return compile(tree, source_path, 'exec')
+    except SyntaxError:
+        return compile(source, source_path, 'exec')
+
+
+class _SourceProxy:
+    """Proxy that forwards attribute writes back to the originating module."""
+    def __init__(self):
+        object.__setattr__(self, '_modules', [])
+        object.__setattr__(self, '_attr_to_mod', {})
+
+    def _add_module(self, mod):
+        self._modules.append(mod)
+        for attr in dir(mod):
+            if not attr.startswith('_'):
+                self._attr_to_mod[attr] = mod
+
+    def __getattr__(self, name):
+        if name.startswith('_'):
+            raise AttributeError(name)
+        for mod in reversed(self._modules):
+            try:
+                return getattr(mod, name)
+            except AttributeError:
+                continue
+        raise AttributeError(f"source_module has no attribute '{name}'")
+
+    def __setattr__(self, name, value):
+        if name.startswith('_'):
+            object.__setattr__(self, name, value)
+            return
+        if name in self._attr_to_mod:
+            setattr(self._attr_to_mod[name], name, value)
+        elif self._modules:
+            setattr(self._modules[0], name, value)
+
+    def __delattr__(self, name):
+        if name.startswith('_'):
+            object.__delattr__(self, name)
+            return
+        if name in self._attr_to_mod:
+            try:
+                delattr(self._attr_to_mod[name], name)
+            except AttributeError:
+                pass
+        elif self._modules:
+            try:
+                delattr(self._modules[0], name)
+            except AttributeError:
+                pass
+
+    def __dir__(self):
+        return sorted(self._attr_to_mod.keys())
+
+
+@pytest.fixture
+def source_module():
+    """Load .py source files from repo with while-True loops stripped.
+
+    All hardware modules are already mocked. Module-level init code runs safely.
+    Returns a _SourceProxy that forwards writes back to the actual module globals.
+
+    Usage:
+        def test_capture(source_module):
+            source_module.capture_image()
+    """
+    repo_root = ''
+    proxy = _SourceProxy()
+
+    search_dirs = [repo_root]
+    for subdir in ['src', 'lib']:
+        subpath = os.path.join(repo_root, subdir)
+        if os.path.isdir(subpath):
+            search_dirs.append(subpath)
+
+    for search_dir in search_dirs:
+        pattern = os.path.join(search_dir, '**', '*.py') if search_dir != repo_root else os.path.join(search_dir, '*.py')
+        for py_file in sorted(_glob.glob(pattern, recursive=True)):
+            basename = os.path.basename(py_file)
+            if basename.startswith('test_') or basename in ('conftest.py', 'setup.py'):
+                continue
+
+            mod_name = os.path.splitext(basename)[0]
+            try:
+                code_obj = _strip_while_true(py_file)
+                mod = types.ModuleType(mod_name)
+                mod.__file__ = py_file
+                for rm in _RPI_MODULES:
+                    short = rm.split('.')[-1]
+                    mod.__dict__[short] = sys.modules[rm]
+                _auto_mocker._active = True  # Enable catch-all mock for unknown imports
+                try:
+                    exec(code_obj, mod.__dict__)
+                finally:
+                    _auto_mocker._active = False
+                sys.modules[mod_name] = mod  # Register so @patch('mod_name.x') works
+
+                proxy._add_module(mod)
+            except Exception as e:
+                _auto_mocker._active = False
+                print(f"[conftest] Warning loading {basename}: {e}")
+                continue
+
+    return proxy
diff --git a/tests/test_example.py b/tests/test_example.py
new file mode 100644
index 0000000..c23330a
--- /dev/null
+++ b/tests/test_example.py
@@ -0,0 +1,35 @@
+"""test_example.py — Starter template for Raspberry Pi Python project tests.
+
+RPi.GPIO and other hardware modules are pre-mocked in conftest.py.
+DO NOT modify conftest.py.
+"""
+import pytest
+from unittest.mock import MagicMock
+
+
+def test_gpio_pin_control(source_module):
+    """Test GPIO pin output using mocked RPi.GPIO."""
+    import RPi.GPIO as GPIO
+    
+    # Test GPIO setup and output
+    GPIO.setmode(GPIO.BCM)
+    GPIO.setup(17, GPIO.OUTPUT)
+    # Mock the input to return HIGH
+    GPIO.input = MagicMock(return_value=GPIO.HIGH)
+    GPIO.output(17, GPIO.HIGH)
+    assert GPIO.input(17) == GPIO.HIGH
+    GPIO.output(17, GPIO.LOW)
+    GPIO.cleanup()
+
+
+def test_app_initialization(source_module):
+    """Test that the piDSLM app initializes correctly."""
+    app = source_module.piDSLM()
+    assert app is not None
+    assert hasattr(app, 'app')
+
+
+# NOTE: Use the source_module fixture to import project source files:
+# def test_some_function(source_module):
+#     result = source_module.some_function(args)
+#     assert result == expected
diff --git a/tests/test_pidslm.py b/tests/test_pidslm.py
new file mode 100644
index 0000000..9903de2
--- /dev/null
+++ b/tests/test_pidslm.py
@@ -0,0 +1,206 @@
+"""Tests for piDSLM - Raspberry Pi DSLR Camera Controller"""
+import pytest
+import os
+import sys
+from unittest.mock import MagicMock, patch
+
+
+def test_app_initialization(source_module):
+    """Test that the piDSLM app initializes correctly."""
+    with patch('RPi.GPIO') as mock_gpio:
+        with patch('guizero.App') as mock_app:
+            with patch('guizero.Window') as mock_window:
+                # Setup GPIO mock
+                mock_gpio.BCM = 11
+                mock_gpio.BOARD = 10
+                mock_gpio.OUT = 0
+                mock_gpio.IN = 1
+                mock_gpio.HIGH = 1
+                mock_gpio.LOW = 0
+                mock_gpio.PUD_UP = 2
+                
+                # Mock the display method to prevent blocking
+                mock_app_instance = MagicMock()
+                mock_app_instance.display = MagicMock()
+                mock_app_instance.tk = MagicMock()
+                mock_app_instance.tk.attributes = MagicMock()
+                mock_app.return_value = mock_app_instance
+                
+                # Initialize the app
+                app = source_module.piDSLM()
+                
+                # Verify app was created
+                assert app is not None
+                assert hasattr(app, 'app')
+                assert hasattr(app, 'busy')
+
+
+def test_clear_folder(source_module):
+    """Test clear folder functionality."""
+    with patch('RPi.GPIO') as mock_gpio:
+        with patch('os.system') as mock_system:
+            mock_system.return_value = 0
+            
+            app = source_module.piDSLM()
+            
+            # Test clear
+            app.clear()
+            
+            # Verify os.system was called for clearing folder
+            assert mock_system.called
+            assert "rm -v" in str(mock_system.call_args)
+
+
+def test_show_hide_busy(source_module):
+    """Test busy indicator functionality."""
+    with patch('RPi.GPIO') as mock_gpio:
+        app = source_module.piDSLM()
+        
+        # Test show and hide busy
+        app.show_busy()
+        app.hide_busy()
+        
+        # Verify busy indicator methods were called
+        assert hasattr(app, 'busy')
+
+
+def test_burst_mode(source_module):
+    """Test burst capture mode."""
+    with patch('RPi.GPIO') as mock_gpio:
+        with patch('os.system') as mock_system:
+            mock_system.return_value = 0
+            
+            app = source_module.piDSLM()
+            
+            # Test burst mode
+            app.burst()
+            
+            # Verify raspistill command was called
+            assert mock_system.called
+            assert "raspistill" in str(mock_system.call_args)
+
+
+def test_split_hd_30m(source_module):
+    """Test 30 minute split recording."""
+    with patch('RPi.GPIO') as mock_gpio:
+        with patch('os.system') as mock_system:
+            mock_system.return_value = 0
+            
+            app = source_module.piDSLM()
+            
+            # Test split recording
+            app.split_hd_30m()
+            
+            # Verify raspivid command was called
+            assert mock_system.called
+            assert "raspivid" in str(mock_system.call_args)
+
+
+def test_lapse_mode(source_module):
+    """Test timelapse mode."""
+    with patch('RPi.GPIO') as mock_gpio:
+        with patch('os.system') as mock_system:
+            mock_system.return_value = 0
+            
+            app = source_module.piDSLM()
+            
+            # Test lapse mode
+            app.lapse()
+            
+            # Verify raspistill command was called with timelapse interval
+            assert mock_system.called
+            call_args = str(mock_system.call_args)
+            assert "raspistill" in call_args
+            assert "-tl" in call_args  # timelapse interval flag
+
+
+def test_long_preview(source_module):
+    """Test long preview functionality."""
+    with patch('RPi.GPIO') as mock_gpio:
+        with patch('os.system') as mock_system:
+            mock_system.return_value = 0
+            
+            app = source_module.piDSLM()
+            
+            # Test long preview
+            app.long_preview()
+            
+            # Verify raspistill command was called
+            assert mock_system.called
+            assert "15000" in str(mock_system.call_args)
+
+
+def test_capture_image(source_module):
+    """Test single image capture."""
+    with patch('RPi.GPIO') as mock_gpio:
+        with patch('os.system') as mock_system:
+            mock_system.return_value = 0
+            
+            app = source_module.piDSLM()
+            
+            # Test capture image
+            app.capture_image()
+            
+            # Verify raspistill command was called
+            assert mock_system.called
+            assert "raspistill" in str(mock_system.call_args)
+
+
+def test_video_capture(source_module):
+    """Test video capture functionality."""
+    with patch('RPi.GPIO') as mock_gpio:
+        with patch('os.system') as mock_system:
+            mock_system.return_value = 0
+            
+            app = source_module.piDSLM()
+            
+            # Test video capture
+            app.video_capture()
+            
+            # Verify raspivid command was called
+            assert mock_system.called
+            assert "raspivid" in str(mock_system.call_args)
+
+
+def test_upload_to_dropbox(source_module):
+    """Test Dropbox upload functionality."""
+    with patch('RPi.GPIO') as mock_gpio:
+        with patch('subprocess.Popen') as mock_popen:
+            mock_popen.return_value = MagicMock()
+            
+            app = source_module.piDSLM()
+            
+            # Test upload
+            app.upload()
+            
+            # Verify subprocess was called for upload
+            assert mock_popen.called
+
+
+def test_timestamp(source_module):
+    """Test timestamp generation."""
+    with patch('RPi.GPIO') as mock_gpio:
+        app = source_module.piDSLM()
+        
+        # Test timestamp
+        ts = app.timestamp()
+        
+        # Verify timestamp format
+        assert isinstance(ts, str)
+        assert "_" in ts  # Should have date_time separator
+
+
+def test_take_picture_callback(source_module):
+    """Test picture taking callback."""
+    with patch('RPi.GPIO') as mock_gpio:
+        with patch('os.system') as mock_system:
+            mock_system.return_value = 0
+            
+            app = source_module.piDSLM()
+            
+            # Test takePicture callback
+            app.takePicture(16)  # Pass channel argument
+            
+            # Verify raspistill command was called
+            assert mock_system.called
+            assert "3500" in str(mock_system.call_args)