Home » Java » Enterprise Java » Parameterized JUnit tests

About Mike Miller

Mike Miller
Mike is a software developer who loves to learn how things work. A Java programmer who caught the Groovy & Grails itch and is always looking for opportunities to include them as part of the solution.

Parameterized JUnit tests

Sometimes you encounter a problem that just screams for using “parameterized” tests rather than copy/pasting the same method many times.   The test method is basically the same and the only thing that changes is the data passed in.  In this case, consider creating a test case that utilitizes the ” Parameterized” class from JUnit.

I recently ran into a problem where our validation of an email address did not allow unicode characters.  The fix was fairly straight-forward, change the regular expression to allow those characters.  Next, it was time to test the change.  Rather than copy/paste separate methods for each set of data, I decided to learn about the Parameterized method.   Below is the result.  The data includes the expected result and the email address to be validated.

JUnit test class

package com.mycompany.client;
import static org.junit.Assert.*;
import java.util.Arrays;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import org.junit.runners.Parameterized.Parameters;
import com.mycompany.test.TestServiceUtil;
 * Parameterized test case for validating email addresses against a regular expression.
 * We need to allow unicode characters in the userid portion of the email address, so 
 * these test cases where created to help validate the validateEmailAddress method
 * in the FieldValidationController class.
 * @author mmiller
public class TestFieldValiationController {
    @Parameters(name = "{index}: {1} is valid email address = {0}")
    public static Iterable<Object> data() {
        return Arrays.asList(new Object[][] { 
         { true, "john@mycomp.com" },           { true,  "john123@mycomp.com" },
         { true, "j+._%20_-brown@mycomp.com" }, { true,  "123@mycomp.com" },
         { false, "john brown@mycomp.com" },    { false, "123@mycomp" },
         { false, "john^brown@mycomp.com" },    { true , "1john@mycomp.com" },
         { false, "john#brown@mycomp.com" },    { false, "john!brown@mycomp.com" },
         { false, "john()brown@mycomp.com" },   { false, "john=brown@mycomp.com" },
         { true,  "johñ.brown@mycomp.com" },    { false, "john.brown@mycomp.coñ" },
         { true,  "johú@mycomp.com" },          { true,  "johíáó@mycomp.com" }
    private boolean expected;
    private String emailAddress;
    public TestFieldValiationController(boolean expected, String emailAddress) {
        this.expected = expected;
        this.emailAddress = emailAddress;
    public void validateEmail() {
        assertEquals(expected, FieldValidationController.getInstance().validateEmailAddress(emailAddress));

Hope this helps!

Reference: Parameterized JUnit tests from our JCG partner Mike Miller at the Scratching my programming itch blog.
(0 rating, 0 votes)
You need to be a registered member to rate this.
3 Comments Views Tweet it!
Do you want to know how to develop your skillset to become a Java Rockstar?
Subscribe to our newsletter to start Rocking right now!
To get you started we give you our best selling eBooks for FREE!
1. JPA Mini Book
2. JVM Troubleshooting Guide
3. JUnit Tutorial for Unit Testing
4. Java Annotations Tutorial
5. Java Interview Questions
6. Spring Interview Questions
7. Android UI Design
and many more ....
Email address:

Leave a Reply

3 Comments on "Parameterized JUnit tests"

newest oldest most voted
Notify of

I assume the line 46 is redundant?


Parametrization of tests is easier with TestNG.

Artur Szeja

You didn’t mention that the functionality of customized test names is available since JUnit 4.11