Unity/Ceedling Test Skill Skill

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));
}

Agent Skills: Unity/Ceedling Test Skill

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Skill Files