Parameterized tests in JUnit Parameterized tests in JUnit can be very useful when writing tests based on tabular data. These type of tests can save you from writing a lot of duplicate or boilerplate code. While there is a fair amount of articles on the subject on the Internet, I wasn’t able to find a code sample that you can simply copy into you…

AddtionTest.java

package com.empoweragile;

import static org.junit.Assert.assertEquals;

import java.util.Arrays;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;

@RunWith(Parameterized.class)
public class AddtionTest {
	
	// since junit 4.11
  	@Parameterized.Parameters(name = "Addition test: {0}+{1}={2}. Test n° {index}")	
	public static Iterable<Object[]> data() {

		return Arrays.asList(new Object[][] { 
				{ 2, 2, 5 }, 
				{ -2, -2, -4 },
				{ 2, 0, 2 }, 
				{ -5, 0, -6 }, 
				{ -3, 3, 0 }, 
				});

	}

	private final int left;
	private final int right;
	private final int expected;

	public AddtionTest(int left, int right, int expected) {
		this.left = left;
		this.right = right;
		this.expected = expected;
	}

	@Test
	public void testAddition() {
		Math math = new Math();
		assertEquals(expected, math.add(left, right));
	}

}

class Math {

	public int add(int left, int right) {
		return left + right;
	}

}