Make jUnit runner run test class multiple times with different parameters

Question

I have some jUnit4 test classes, which I want to run multiple times with different parameters passed in annotation. For example, like this:

@RunWith(MyClassRunner.class)
@Params("paramFor1stRun", "paramFor2ndRun")
class MyTest {
  @Test
  public void doTest() {..}
}

I assume Runner can help me with it, but I don't know how to implement this. Could you advice please?

Answer 1

1. You need to add the annotation @RunWith(Parameterized.class) to your test.

2. Then, create a constructor for you class with the parameters you need:

   public Test(String pParam1, String param2) {
       this.param1 = pParam1;
       this.param2 = pParam2;
   }
   

3. Then, declare a method like this (Which provides an array of parameters corresponding to the constructor):

   @Parameters
   public static Collection<Object[]> data() {
     Object[][] data = {{"p11", "p12"}, {"p21", "p22"}};
     return Arrays.asList(data);
   }
   

4. You can do you test, which will be executing for each row of your array:

   @Test
   public void myTest() {  
       assertEquals(this.param1,this.param2);
   }
   

You've got a faster way without defining the constructor, if you use the annotation @Parameter(value = N) where N is the index of you parameter array.