How to use assertion function in PHP

This article will introduce to you how to use the assertion function 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 captured 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will have an obsolete reminder, indicating that the expression type of the string type passed to the assert() function is obsolete.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_ACTIVEassert.active1Enable assert() assertionASSERT_WARNINGassert.warning 1Generate a PHP warning for each failed assertionASSERT_BAILassert.bail0Abort execution on assertion failureASSERT_QUIET_EVALassert.quiet_eval0In assertion expression Disable error_reporting when evaluatingASSERT_CALLBACKassert.callback(NULL)Callback function called when assertion fails

  这些参数的含义都非常好理解，大家可以自己测试一下。我们就来看一下最后一个 ASSERT_CALLBACK 的作用。其实它的说明也非常清楚，就是断言失败的情况下就进入到这个选项定义的回调函数中。

  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====

  当断言失败的时候，我们就进入了回调函数中，在回调函数直接简单的打印了传给回调函数的参数内容。可以看出，这个回调函数里面传递过来的是无法通过断言的文件信息。

  总结

  学习掌握一下断言函数的使用及配置，可以为我们将来学习 PHPUnit 单元测试打下基础，当然，本身这个能力的东西就不是很多，大家记住就好啦！

  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

  推荐学习：php视频教程

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