Java - Junit - How do I write and run a simple test?

Steps on how to write a sample junit test.

Write a SimpleTest.java file

// 1-  Create a class:
 
import org.junit.*;
import static org.junit.Assert.*;
 
import java.util.*;
 
public class SimpleTest {
 
// 2 - Write a test method (annotated with @Test) that asserts expected results on the object under test:
 
    @Test
    public void testEmptyCollection() {
    Collection collection = new ArrayList();
    assertTrue(collection.isEmpty());
    }
 
// 3 - If you are running your JUnit 4 tests with a JUnit 3.x runner, write a suite() method that uses the 
//     JUnit4TestAdapter class to create a suite containing all of your test methods:
 
    public static junit.framework.Test suite() {
        return new junit.framework.JUnit4TestAdapter(SimpleTest.class);
    }
 
// 4 - Although writing a main() method to run the test is much less important with the advent of IDE runners,
// it's still possible:
 
    public static void main(String args[]) {
         org.junit.runner.JUnitCore.main("SimpleTest");
    }
}

Download the Junit jar file and add it to the CLASSPATH.

set CLASSPATH=%CLASSPATH%;C:\temp\class\junit-4.8.1.jar
javac SimpleTest.java

• from the console:

java org.junit.runner.JUnitCore SimpleTest
JUnit version 4.8.1
.
Time: 0,006

OK (1 test)

• with the test runner used in main(), type:

java SimpleTest
JUnit version 4.8.1
.
Time: 0,007

OK (1 test)

• How do I write and run a simple test?