Testing

The QtNodes library includes a comprehensive unit test suite built with Catch2.

Test Coverage

The test suite covers the following areas:

Core Functionality (20 test cases, 216 assertions)

• AbstractGraphModel operations (node CRUD, connections)
• AbstractGraphModel signal emissions (comprehensive signal testing)
• DataFlowGraphModel functionality
• NodeDelegateModelRegistry operations
• Serialization (save/load JSON)
• Undo system integration
• Graphics scene management
• Connection ID utilities

Data Flow Testing (5 test cases, 46 assertions)

• Real data transfer between connected nodes using NodeDelegateModel pattern
• Programmatic and interactive connection creation with data propagation
• Multiple output connections (one-to-many data distribution)
• Connection lifecycle testing (creation, data flow, disconnection)
• Custom node delegate models with embedded widgets and signal handling

Visual UI Interaction Testing (3 test cases, 5 assertions)

• Node movement and visual positioning
• Connection creation by dragging between ports
• Connection disconnection by dragging and deletion
• Zoom and pan operations
• Keyboard shortcuts (delete, undo)
• Context menu interactions
• Stress testing with rapid mouse movements and UI load

Total: 28 test cases, 267 assertions

Infrastructure

• Complete AbstractGraphModel test implementation
• Qt application setup utilities
• Node delegate stubs for testing
• UITestHelper namespace for UI interaction simulation
• Virtual display testing with proper window exposure
• Clean build system without internal dependencies

Running Tests

From the build directory:

.. code-block:: bash

# Build tests
make test_nodes

# Run all tests
./bin/test_nodes

# Run specific test categories
./bin/test_nodes "[core]"        # Core functionality
./bin/test_nodes "[signals]"     # Signal emission tests
./bin/test_nodes "[dataflow]"    # DataFlowGraphModel tests
./bin/test_nodes "[registry]"    # Registry tests
./bin/test_nodes "[serialization]"  # Save/load tests
./bin/test_nodes "[undo]"        # Undo system tests
./bin/test_nodes "[graphics]"    # Graphics tests
./bin/test_nodes "[ui]"          # UI interaction tests
./bin/test_nodes "[visual]"      # Visual UI tests
./bin/test_nodes "[stress]"      # Stress tests

Test Structure

Tests are organized in test/ directory:

.. code-block::

test/
├── CMakeLists.txt              # Build configuration
├── include/
│   ├── ApplicationSetup.hpp    # Qt app setup
│   ├── TestGraphModel.hpp      # Test graph model
│   └── TestDataFlowNodes.hpp   # Node delegate stub
└── src/
    ├── TestAbstractGraphModel.cpp
    ├── TestAbstractGraphModelSignals.cpp
    ├── TestDataFlowGraphModel.cpp
    ├── TestNodeDelegateModelRegistry.cpp
    ├── TestBasicGraphicsScene.cpp
    ├── TestConnectionId.cpp
    ├── TestCopyPaste.cpp
    ├── TestCustomPainters.cpp
    ├── TestLoopDetection.cpp
    ├── TestNodeValidation.cpp
    ├── TestSerialization.cpp
    ├── TestUIInteraction.cpp
    ├── TestUndoCommands.cpp
    └── TestZoomFeatures.cpp

Test Categories

Core Tests ([core])

• AbstractGraphModel basic functionality
• Connection management
• Node deletion with connections
• ConnectionId utilities and edge cases

Signal Tests ([signals])

• Signal emission verification for all AbstractGraphModel signals
• Signal spy validation and argument type checking
• Signal consistency with model state
• Edge case signal behavior (invalid operations)
• Complex operation signal ordering

DataFlow Tests ([dataflow])

• DataFlowGraphModel operations
• Node creation and validation
• Connection possibility checks
• Port bounds validation

Registry Tests ([registry])

• NodeDelegateModelRegistry functionality
• Model registration with categories
• Lambda factory registration
• Category associations

Serialization Tests ([serialization])

• DataFlowGraphModel serialization
• Individual node serialization
• JSON save/load operations

Undo System Tests ([undo])

• QUndoStack integration with BasicGraphicsScene
• Manual undo/redo simulation
• State tracking

Graphics Tests ([graphics])

• BasicGraphicsScene functionality
• Graphics undo/redo support
• Scene management

UI Interaction Tests ([ui], [visual], [stress])

• Node movement and visual positioning using UITestHelper namespace
• Connection creation by dragging between ports
• Connection disconnection by dragging from ports and deletion of selected connections
• Zoom and pan operations with mouse wheel and drag
• Keyboard shortcuts (delete key, Ctrl+Z undo)
• Context menu interactions (right-click)
• Stress testing with rapid mouse movements and memory load
• Virtual display testing with proper window exposure handling

Validation Tests ([validation])

• NodeValidationState struct functionality
• NodeProcessingStatus enum values
• Setting validation and processing status through NodeDelegateModel
• Integration with DataFlowGraphModel

Custom Painters Tests ([painters])

• Custom node painter registration
• Custom connection painter registration
• Painter replacement behavior
• Paint method invocation verification

Copy/Paste Tests ([copypaste])

• Single node copy
• Multiple node copy with connections
• Paste operations
• Duplicate operations (Ctrl+D)

Zoom Tests ([zoom])

• Scale range configuration
• zoomFitAll behavior
• zoomFitSelected behavior
• scaleChanged signal emission

Loop Detection Tests ([loops])

• loopsEnabled configuration in AbstractGraphModel
• DataFlowGraphModel loop prevention
• Direct self-loop prevention
• Indirect cycle detection

Key Features

Segfault Resolution: Fixed critical infinite recursion in signal emission that was causing stack overflow crashes during graphics system updates.

API Modernization: Updated from v2.x to v3.x Model-View architecture with proper AbstractGraphModel implementation following QtNodes best practices.

Clean Dependencies: Removed internal header dependencies, using only public APIs for better stability and maintainability.

Signal Emission Testing: Comprehensive verification of all AbstractGraphModel signals using QSignalSpy, ensuring proper signal emission for all operations including node creation/deletion, connection creation/deletion, and node updates.

Comprehensive Coverage: Tests all major functionality including node management, connections, serialization, undo system, and graphics integration.

Port Bounds Validation: Added proper validation in connectionPossible() to ensure port indices are within valid ranges.

Building Tests

Tests are built automatically when BUILD_TESTING is enabled (default).

Prerequisites:

• Catch2 testing framework
• Qt6 (or Qt5 with appropriate configuration)
• CMake 3.8+

Configuration:

.. code-block:: bash

# Enable testing (default)
cmake .. -DBUILD_TESTING=ON

# Disable testing
cmake .. -DBUILD_TESTING=OFF

Build:

.. code-block:: bash

# Build library and tests
make

# Build only tests
make test_nodes

Test Implementation Details

TestGraphModel: A complete implementation of AbstractGraphModel that provides:

• Full node and connection management
• Proper signal emission patterns
• Serialization support
• Integration with graphics systems

UITestHelper: A namespace providing utility functions for UI interaction testing:

• simulateMousePress/Move/Release() - Low-level mouse event simulation
• simulateMouseDrag() - High-level drag operation simulation
• waitForUI(ms = 10) - Optimized UI event processing with 10ms default timing
• Proper Qt event system integration for realistic UI testing

Signal Safety: The test model implements signal emission patterns that prevent infinite recursion between the model and graphics system, following the approach used in examples/simple_graph_model.

Mock Objects: Comprehensive stub implementations for testing without external dependencies, including StubNodeDataModel for node delegate testing.

Troubleshooting

Common Issues:

• Catch2 not found: Install Catch2 or disable testing with -DBUILD_TESTING=OFF
• Qt version conflicts: Ensure consistent Qt5/Qt6 usage throughout build
• Missing test binary: Check that BUILD_TESTING is enabled in CMake configuration

Performance Notes:

• Tests include Qt application setup overhead
• Graphics tests may show Qt warnings about runtime directories (these are harmless)
• UI tests use optimized 10ms timing for consistent performance
• Full test suite typically completes in under 10 seconds