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/*
* Copyright 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @file assert_module.c
* @brief Example demonstrating how to mock assert() with cmocka
*
* This file shows a critical testing technique: overriding standard assert()
* with cmocka's mock_assert() to enable testing of assertion failures without
* crashing the test program.
*
* Key concepts:
* 1. When UNIT_TESTING is defined, assert() is replaced with mock_assert()
* 2. mock_assert() is provided by cmocka and can be controlled in tests
* 3. This allows testing that functions correctly assert on invalid input
*/
#include <assert.h>
#include "assert_module.h"
/*
* If unit testing is enabled, override assert() with mock_assert().
*
* This is a powerful pattern for testing code that uses assertions:
* - In production (UNIT_TESTING not defined): normal assert() behavior
* - In tests (UNIT_TESTING defined): assertions become testable events
*
* The mock_assert() function is provided by cmocka and works with
* expect_assert_failure() in test code.
*/
#ifdef UNIT_TESTING
extern void mock_assert(const int result,
const char *const expression,
const char *const file,
const int line);
#undef assert
#define assert(expression) \
mock_assert(((expression) ? 1 : 0), #expression, __FILE__, __LINE__);
#endif /* UNIT_TESTING */
/**
* @brief Increment an integer value with assertion
*
* This function demonstrates defensive programming with assert().
* The assert() ensures the pointer is valid before dereferencing.
*
* When compiled with UNIT_TESTING, the assert becomes testable:
* - Tests can verify the assert fires on NULL input
* - The test doesn't crash; cmocka catches the assertion
*/
void increment_value(int *const value)
{
assert(value);
(*value)++;
}
/**
* @brief Decrement an integer value with runtime check
*
* This function demonstrates a different validation approach: runtime
* checking with if statements instead of assertions.
*
* Comparison with increment_value():
* - increment_value() uses assert() - fails fast in debug, removed in release
* - decrement_value() uses if check - always present, silently handles NULL
*
* The test suite shows how these different approaches behave differently
* when tested with expect_assert_failure().
*/
void decrement_value(int *const value)
{
if (value) {
(*value)--;
}
}
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