Unity/Ceedling Test Skill

Overview

This skill provides embedded unit testing capabilities using the Unity test framework, CMock mock generation, and Ceedling build system for comprehensive off-target and on-target testing.

Capabilities

Unity Test Framework

• Test case generation
• Assertion macro usage
• Test fixture setup/teardown
• Test group organization
• Parameterized tests
• Custom assertions

CMock Mock Generation

• Automatic mock generation from headers
• HAL/driver mocking strategies
• Callback mocking
• Argument capture and validation
• Return value configuration
• Call count verification

Ceedling Build System

• Project configuration (project.yml)
• Test runner generation
• Coverage integration
• Compiler configuration
• Plugin management
• CI/CD integration

Hardware Abstraction Mocking

• Register mock strategies
• DMA mock patterns
• Interrupt mock handling
• Timing mock approaches
• State machine mocking

Test Coverage

• gcov integration
• lcov report generation
• Branch coverage analysis
• MC/DC coverage (for safety)
• Coverage threshold enforcement

Off-Target Testing

• Host compilation setup
• Platform abstraction
• Stub implementation
• Double buffering for DMA
• Fake timer implementations

Target Processes

• embedded-unit-testing.js

  - Unit test implementation

• device-driver-development.js

  - Driver testing

• bsp-development.js

  - BSP unit testing

Dependencies

• Unity test framework
• CMock mock generator
• Ceedling build system (optional)
• gcov/lcov for coverage

Usage Context

This skill is invoked when tasks require:

• Unit test development
• Mock generation for drivers
• Test coverage analysis
• Off-target testing setup
• TDD for embedded

Project Structure

project/
  src/
    driver.c
    driver.h
  test/
    test_driver.c
    support/
      test_helper.c
  build/
    test/
    artifacts/
  project.yml

Configuration Example (project.yml)

:project:
  :build_root: build/
  :test_file_prefix: test_
  :use_exceptions: FALSE

:paths:
  :test:
    - test/**
  :source:
    - src/**
  :include:
    - inc/**

:cmock:
  :mock_prefix: mock_
  :when_no_prototypes: :warn
  :enforce_strict_ordering: TRUE
  :plugins:
    - :ignore
    - :callback
    - :return_thru_ptr

:plugins:
  :enabled:
    - gcov
    - xml_tests_report

Test Example

#include "unity.h"
#include "driver.h"
#include "mock_hal_spi.h"

void setUp(void) {
    driver_init();
}

void tearDown(void) {
    driver_deinit();
}

void test_driver_sends_correct_command(void) {
    uint8_t expected[] = {0x01, 0x02, 0x03};

    HAL_SPI_Transmit_ExpectWithArrayAndReturn(
        SPI1, expected, 3, 3, 100, HAL_OK);

    TEST_ASSERT_EQUAL(DRIVER_OK, driver_send_command(0x01));
}