As a test, how to understand thread synchronization and asynchrony

background

In daily tests , Program loading data file , Page jams often appear 、 Program not responding 、 Program crash, etc , The troubleshooting found that it is related to the synchronization and asynchrony of threads in the program process .

Case description

Problem description ：

When opening a compressed file using the file viewer , There is a problem that the program is not responding .
Question why ：

1、 After investigation, it was found that , When the file viewer opens the compressed file , It will traverse all resources in the compressed file , A resource parsing error occurred during traversal , Cause task blocking .

2、 After further understanding, it is found that , When developing functions , Put the resource traversal thread in the main thread for synchronous loading , So when the resource traversal thread is blocked , Cause the main thread to be unresponsive .
Solution ：

1、 Add protection to the resource traversal thread blocking scenario , Ensure that the traversal thread executes normally ;
2、 Put the resource traversal compressed file thread from the main thread to the sub thread , Form asynchronous loading , Avoid a single thread failure that causes the main thread to hang up directly , Affect program use ;

It can be seen from the above cases that , Use synchronous or asynchronous threads in logical implementation , It is very important to improve the efficiency of the program and protect the main thread .

Extended thinking

1、 The development layer uses threads ：

1. Scenarios using threads ：
   ① Move APP The program module needs to load the framework + Content time , Using threads is more efficient ;
   ② When optimizing program performance , Prefer to use threads ;
2. Application of thread synchronization and asynchrony in program ：
   ① When the main thread executes a task , Execute asynchronous tasks in sub threads , The main thread does not need to wait for the result of the child thread to return , Complete the operation on the main thread , Wait for the result of the sub thread to return , Then call back to the main thread , Complete the whole process . This is the asynchronous loading operation of the thread , This can improve the efficiency of execution （ Here's the picture ）;
   ② The main thread is executing the task 1 when , Task waiting 1 After response , To start the task 2, Such as the task 1 Blocking , Then the whole process cannot proceed , Such synchronous threads have a great impact on the execution efficiency （ Here's the picture ）.
   
   2、 The impact of threads on testing ：
   1） The thread of case Design impact ：
   ① The function of data stream loading class . Most of these functions are asynchronous threads , You can consider testing from the network level and loading level case The design of the ;
   ② JS Function of injection class . Such functions are mostly synchronous threads , You can inject JS Effectiveness of functions and JS Injection timing consider testing case The design of the .
   2） The impact of threads on program performance ：
   ① From the perspective of safety and performance , Synchronous thread solves the thread safety problem , But every time there is a judgment lock , Resulting in reduced performance ;
   ② Compared with synchronous threads , Asynchronous threads have a positive impact on program performance , More efficient , commonly APP Asynchronous threads are recommended in programs , Ensure the efficiency of the program .

Be careful ： Between safety and performance , The first consideration is safety , The second is performance .

Conclusion

Understanding program implementation logic is essential in testing , Only understand in more detail and more clearly , In order to have a more comprehensive thinking about the test plan , So as to ensure product quality . Here, I hope you guys are more and more skilled , Go higher and higher on the road of software testing ！

The house needs to be built layer by layer , Knowledge needs to be learned at one point one . We should lay a good foundation in the process of learning , More hands-on practice , Don't talk much , The last dry goods here ！ I stayed up late to sort out the stages ( function 、 Interface 、 automation 、 performance 、 Test open ) Skills learning materials + Practical explanation , Very suitable for studying in private , It's much more efficient than self-study , Share with you .

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