How Test Runners interacting with main method

Question

Hi ,

In my View Static void main() -- is the starting point for execution. but test runners dont have  main() method. how execution is happening .

Answer 1

 As main() method is needed to run the Java program and while writing tests in TestNg we don't use main() method,we use Annotations instead.

Annotations in TestNG are lines of code that can control how the method below them will be executed. So, in short you don't need to write main() method, TestNg do that by itself.

You can refer code at the end in Annotations documentation to get the idea how it happens.

Hope it is helpfull!!
Thank you!!

Comments

Hi @Niroj,

thanks for ur quick response.

1)  Unit test Framework  have annotations , that will take care of what methods to be execute at what time we know this.

2) My Question is, in order to start an execution we need a main() method , without this  execution wont start . this is the entry point .

3) How Unit test Framework   are handling this.

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Hey, Check this out https://www.smartclient.com/smartgwt/javadoc/com/smartgwt/client/docs/TestRunner.html#:~:text=The%20Smart%20GWT%20TestRunner%20is,tests%20that%20were%20previously%20failing.

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Hello @sri,
Yes, we can execute a java program without a main method by using a static block. 

Static block in Java is a group of statements that gets executed only once when the class is loaded into the memory by Java ClassLoader, It is also known as a static initialization block. 

Example:

class StaticInitializationBlock{   
static{     
System.out.println("class without a main method");     
System.exit(0); 
}
}