A brief discussion on the usage of assertion functions in PHP

This article will teach you how to use assertion functions in PHP. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to everyone.

I originally thought that the assertion-related functions were provided by PHPUnit and these unit test components. After reading the manual, I discovered that the assert() assertion function comes with PHP itself. a function of. In other words, when we perform simple tests in the code, we do not need to completely introduce the entire unit test component.

assert() assertion function

assert(1==1);

assert(1==2);
// assert.exception = 0 时，Warning: assert(): assert(1 == 2)
// assert.exception = 1 时，Fatal error: Uncaught AssertionError: 验证不通过

Obviously, the second piece of code cannot pass assertion verification. At this time, PHP will return a warning or exception error. Why are there two possible error forms? When we set assert.exception in php.ini to off or 0, that is, when we turn off the ability of this parameter, the program will still return a warning in the form of PHP5, just like the comment in the code above. At the same time, exceptions cannot be caught through try...catch. This parameter actually controls whether to throw an authentic exception object. If you keep this parameter as the default, that is, set to on or 1, an exception will be thrown directly and the program will terminate.

As can be seen from the above code, the first parameter of the assertion is an expression, and it requires an expression that returns a bool type object. What if we pass a string or a number?

// 设置 assert.exception = 0 进行多条测试

assert(" ");
// Deprecated: assert(): Calling assert() with a string argument is deprecated
// Warning: assert(): Assertion " " failed

assert("1");
// Deprecated: assert(): Calling assert() with a string argument is deprecated

assert(0);
// Warning: assert(): assert(0) failed

assert(1);

assert("1==2");
// Deprecated: assert(): Calling assert() with a string argument is deprecated
// Warning: assert(): Assertion "1==2" failed

Obviously, the expression of the first parameter will be type casted, but the string type will have an obsolete reminder, indicating that the expression type of the string type passed to the assert() function is obsolete. . The current test version is 7.3. In the future, errors or exceptions that terminate the operation may be directly reported. The main problem is that if the passed string itself is also an expression, the judgment will be based on the content of this expression, which can easily lead to ambiguity, just like the last piece of code. Of course, the outdated usage method is still not recommended. Here is just an understanding.

Next let’s take a look at the other parameters of the assert() function. Its second parameter is of two types, either a string used to define error information, or an exception class used to throw Exception occurred.

assert(1==1, "验证不通过");

assert(1==2, "验证不通过");
// Warning: assert(): 验证不通过 failed

If a string is given directly, then the content of the error message we defined will be displayed in the warning message. This is very easy to understand.

// 注意 assert.exception 设置不同的区别

assert(1==1,  new Exception("验证不通过"));

assert(1==2,  new Exception("验证不通过"));
// assert.exception = 1 时，Fatal error: Uncaught Exception: 验证不通过
// assert.exception = 0 时，Warning: assert(): Exception: 验证不通过

Of course, we can also give an exception class to let the assertion throw an exception. By default, the throwing of this exception will abort the execution of the program. That is a normal exception throwing process. We can use try...catch to catch exceptions.

try{
    assert(1==2,  new Exception("验证不通过"));
}catch(Exception $e){
    echo "验证失败！:", $e->getMessage(), PHP_EOL;
}
// 验证失败！:验证不通过

There is another parameter that will affect the overall operation of assertions, that is the zend.assertions parameter in php.ini. It contains three values:

• 1, which generates and executes the code. Generally,
• 0 is used in the test environment. The code is generated but will pass through
• - during runtime. 1. No code is generated. Generally,

is used in the formal environment. You can configure the test by yourself. The default value in the default php.ini is 1, which is the normal execution of the assert() function. .

assert_options() and the corresponding parameter configuration in php.ini

The assertion function in PHP also provides us with an assert_options() function for Conveniently set and obtain some parameter configurations related to assertion capabilities. The assertion flags it can set include:

Flags | INI Settings | Default Value | Description

• | :-: | :-: | -:

ASSERT_ACTIVE | assert.active | 1 | Enable assert() assertion ASSERT_WARNING | assert.warning | 1 | Generate a PHP warning for each failed assertion ASSERT_BAIL | assert.bail | 0 | Abort execution on assertion failure ASSERT_QUIET_EVAL | assert.quiet_eval | 0 | Disable error_reporting when assertion expressions are evaluated ASSERT_CALLBACK | assert.callback | (NULL) | Call the callback function when the assertion fails

The meaning of these parameters is very easy to understand, you can test it yourself. Let’s take a look at the function of the last ASSERT_CALLBACK. In fact, its description is also very clear, that is, if the assertion fails, it will enter the callback function defined by this option.

assert_options(ASSERT_ACTIVE, 1);
assert_options(ASSERT_WARNING, 1);
assert_options(ASSERT_BAIL, 1);

assert_options(ASSERT_CALLBACK, function($params){
    echo "====faild====", PHP_EOL;
    var_dump($params);
    echo "====faild====", PHP_EOL;
});

assert(1!=1);
// ====faild====
// string(105) ".../source/一起学习PHP中断言函数的使用.php"
// ====faild====

When the assertion fails, we enter the callback function, and the callback function simply prints the content of the parameters passed to the callback function. It can be seen that the file information passed in this callback function cannot pass the assertion.

Summary

Learning to master the use and configuration of assertion functions can lay the foundation for us to learn PHPUnit unit testing in the future. Of course, there are not many things with this ability. , just remember it everyone!

测试代码：
https://github.com/zhangyue0503/dev-blog/blob/master/php/202005/source/%E4%B8%80%E8%B5%B7%E5%AD%A6%E4%B9%A0PHP%E4%B8%AD%E6%96%AD%E8%A8%80%E5%87%BD%E6%95%B0%E7%9A%84%E4%BD%BF%E7%94%A8.php

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