How to parameterize junit Test Suite

Question

Is it possible to parameterize a TestSuite in junit 4 ?

For declaring a class as a test suite I need the annotation @RunWith(Suite.class), but the same annotation is also needed to declare the test as parameterized: @RunWith(Parameterized.class) so I cannot add both to the same class.

I found a similar question in this site that did not help much. So far, all the examples I have found explain how to parameterize simple unit tests, not a complete test tuite.

Answer 1

I believe the basic answer is No, because as you said, the @RunsWith only take one parameter. I found a blog posting that got a bit creative in how to handle this situation.

We don't use the parameterized tests, but may you could create a separate suite like we do that only lists the test classes and the parameterized test could be part of that. I modified our test suite to include a parameterized test class to part of the suite and it ran fine. We create our suite like below where PrimeNumberCheckerTest was a simple I pulled from the web.

package com.jda.portfolio.api.rest.server;

import org.junit.runner.RunWith;
import org.junit.runners.Suite;
import org.junit.runners.Suite.SuiteClasses;

@RunWith(Suite.class)
@SuiteClasses({  com.mycompany.api.rest.server.resource.TestCartResourceJava.class, 
                 com.mycompany.api.rest.server.resource.TestCustomerResource.class,
                 com.mycompany.api.rest.server.resource.TestWizardProfileResource.class,
                 com.mycompany.api.rest.server.interceptor.TestBaseSearchInterceptor.class, 
                 com.mycompany.api.rest.server.resource.TestQueryParameters.class, 
                 com.mycompany.api.rest.server.expression.TestCartExpressionGenerator.class, 
                 com.mycompany.api.rest.server.expression.TestPreferenceExpressionGenerator.class, 
                 com.mycompany.api.rest.server.PrimeNumberCheckerTest.class, 
                 })
public class AllTests {}

Here's the source for the parameterized test case;

package com.jda.portfolio.api.rest.server:

import static org.junit.Assert.*;
import java.util.Arrays;
import java.util.Collection;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import org.junit.runners.Suite.SuiteClasses;

@RunWith(Parameterized.class)
@SuiteClasses({PrimeNumberCheckerTest.class})
public class PrimeNumberCheckerTest {
  private Integer inputNumber;
  private Boolean expectedResult;
  private PrimeNumberChecker primeNumberChecker;

  @Before
  public void initialize() {
     primeNumberChecker = new PrimeNumberChecker();
  }

  // Each parameter should be placed as an argument here
  // Every time runner triggers, it will pass the arguments
  // from parameters we defined in primeNumbers() method
  public PrimeNumberCheckerTest(Integer inputNumber, 
     Boolean expectedResult) {
     this.inputNumber = inputNumber;
     this.expectedResult = expectedResult;
  }

  @Parameterized.Parameters
  public static Collection primeNumbers() {
     return Arrays.asList(new Object[][] {
        { 2, true },
        { 6, false },
        { 19, true },
        { 22, false },
        { 23, true }
     });
  }

  // This test will run five times since we have as many parameters defined
  @Test
  public void testPrimeNumberChecker() {
     System.out.println("Parameterized Number is : " + inputNumber);
     assertEquals(expectedResult, 
     primeNumberChecker.validate(inputNumber));
  }