The **`@Before`** annotation is used when different test cases share the same logic. 

> The method with the `@Before` annotation always runs before the execution of each test case. 

This annotation is commonly used to develop necessary preconditions for each `@Test` method.

#   
## Syntax

```Java
@Before
public void beforeTest() {}
``` 

## Code
Let's run the code for the `@Before` annotation.




 import org.junit.*;                

public class demoTest { 

    //indicates that this method will run before the each @Test method
    @Before 
     public void beforetest() {
        System.out.println("@Before method is running");
    }

    //First testcase
    @Test 
    public void testcase1() {
         System.out.println("Testcase 1 is running");
    }
    
    //Second testcase
    @Test
    public void testcase2() {
       System.out.println("Testcase 2 is running");
    }
}

import React from 'react';
import { shallow, configure } from 'enzyme';
import Adapter from 'enzyme-adapter-react-16';

configure({ adapter: new Adapter() });

import HelloWorld from './app';

var TestResult = function() {
    this.succeeded = false;
    this.reason = "";
    this.input = "";
    this.expected_output = "";
    this.actual_output = "";
}

export const executeTests = function() {

  var results = [];

  result = new TestResult();
  result.input = 'HelloWorld Component';
  result.expected_output = "span containing text 'Hello World'"

  let wrapper = shallow(<HelloWorld />);

  // Call your Challenge function here.

  let type = wrapper.type();
  let testSuccessful = true;
  let failureReason;

  if (type !== 'span') {
    testSuccessful = false;
    failureReason = "You need to render exactly one span HTML element";
  } else if (wrapper.props().children != "Hello World") {
     testSuccessful = false;
     failureReason = "You have rendered wrong message in your span element";
  }

  result.actual_output = wrapper.html();

  if (testSuccessful) {
    result.succeeded = true;
    result.reason = "Succeeded"
  } else {
    result.succeeded = false;
    result.reason = failureReason;
  }

  results.push(result);

  return results;
}


Java

React

Dart

GoJS React

Typescript React

Vue.js

As you can see, the method with the `@Before` annotation is run twice. `OK (2 tests)` indicates that both test cases are passing.

> Keep in mind that JUnit 5 supports `@BeforeEach` instead of `@Before`.

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What is the @Before annotation in JUnit testing?

Syntax

Code

Explanation