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JUnit test fixtures

JUnit test fixtures are a set of objects and pre-configured conditions that are created before the execution of a test case. A test fixture is used to provide a known and controlled environment for the test case to run in, making it easier to test the code under specific conditions.

A test fixture can be created by defining instance variables and initializing them in a @Before method. The @Before method is a JUnit lifecycle method that is executed before each test case in the test class. This allows you to set up a fresh fixture for each test case, making it easier to isolate the tests from each other.

Here is an example of a JUnit test fixture:

import org.junit.Before;
import org.junit.Test;

import static org.junit.Assert.assertEquals;

public class ExampleTestFixture {
    private String message;
    private MessageUtil messageUtil;

    @Before
    public void setUp() {
        message = "hello world";
        messageUtil = new MessageUtil(message);
    }

    @Test
    public void testPrintMessage() {
        assertEquals(message, messageUtil.printMessage());
    }

    @Test
    public void testSalutationMessage() {
        message = "Hi!" + message;
        assertEquals(message, messageUtil.salutationMessage());
    }
}

In this example, the test fixture is created by defining the instance variables message and messageUtil, and initializing them in the setUp method. The setUp method is annotated with @Before, so it will be executed before each test case in the test class.

The two test cases, testPrintMessage and testSalutationMessage, use the fixture created in the setUp method to test the printMessage and salutationMessage methods of the MessageUtil class, respectively.

This way, each test case runs in a controlled environment, and any changes made to the fixture in one test case do not affect the other test cases, making it easier to test the code and ensure that it works correctly.



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