Safe Unity Test Runner

A safe test execution wrapper for the Unity test framework in ESP-IDF projects, designed to prevent test crashes from terminating the entire test suite.

Overview

The Safe Unity component provides isolated test execution for Unity framework tests by running each test in a separate child process. This isolation prevents crashes, segmentation faults, or other fatal errors in individual tests from affecting the test runner or other tests.

Features

• Process Isolation: Each test runs in a separate child process
• Crash Protection: Handles common crash signals (SIGSEGV, SIGABRT, SIGFPE, SIGILL, SIGBUS)
• Code Coverage Support: Integrates with gcov for code coverage collection
• Detailed Reporting: Provides clear test result reporting with crash detection
• Linux Host Testing: Specifically designed for ESP-IDF host-based unit testing

Supported Platforms

• Linux only: This component is designed specifically for Linux host-based testing
• ESP targets: Not supported (component automatically returns for ESP targets)

Basic Usage

Simple Test Execution

#include "safe_unity.h"

void test_example_function(void)
{
    TEST_ASSERT_EQUAL(42, my_function_that_returns_42());
}

void app_main(void)
{
    UNITY_BEGIN();
    
    // Run test safely - crashes won't terminate the test runner
    RUN_TEST_SAFE(test_example_function);
    
    UNITY_END();
}

API Reference

Macros

RUN_TEST_SAFE(func)

Safely executes a Unity test function in an isolated process.

Parameters:

• func: Unity test function to execute

Example:

RUN_TEST_SAFE(my_test_function);

How It Works

Process Isolation

1. Fork Process: For each test, a child process is created using fork()
2. Signal Handling: The child process registers signal handlers for crash detection
3. Test Execution: The test runs with proper Unity setup/teardown in the child process
4. Result Collection: The parent process waits for the child and analyzes the exit status
5. Coverage Flush: Code coverage data is flushed before process termination

Signal Handling

The component handles the following signals in child processes:

• SIGSEGV: Segmentation fault
• SIGABRT: Abort signal
• SIGFPE: Floating point exception
• SIGILL: Illegal instruction
• SIGBUS: Bus error

When any of these signals are received, the test is marked as crashed and the process exits gracefully after flushing coverage data.

Code Coverage Integration

The component automatically integrates with gcov for code coverage collection:

• Coverage data is flushed before each test process exits
• Both passing and crashing tests contribute to coverage statistics
• No additional configuration required when using --coverage flags

Build Configuration

The component requires the following CMake configuration:

# In your project's CMakeLists.txt
if(${target} STREQUAL "linux")
    idf_component_register(
        SRCS "your_test.c"
        INCLUDE_DIRS "."
        REQUIRES safe_unity
    )
endif()

Examples

Complete Test Suite

#include "safe_unity.h"

void setUp(void) {
    // Test setup code
}

void tearDown(void) {
    // Test cleanup code
}

void test_normal_operation(void) {
    TEST_ASSERT_EQUAL(42, my_function());
}

void test_edge_case(void) {
    TEST_ASSERT_NULL(my_function_with_null_return());
}

void test_potential_crash(void) {
    // This might crash in some conditions
    my_risky_function();
    TEST_ASSERT_TRUE(true);
}

void app_main(void) {
    UNITY_BEGIN();
    
    RUN_TEST_SAFE(test_normal_operation);
    RUN_TEST_SAFE(test_edge_case);
    RUN_TEST_SAFE(test_potential_crash);
    
    UNITY_END();
}