Create multiple parameter sets in one parameterized class (junit)

Question

Currently I have to create a parameterized test class for every method that I want to test with several different inputs. Is there a way to add this together in one file?

Right now there's CalculatorTestAdd.java which has a set of parameters that are used to check if the Add() function works properly. Is there a possbility for me to 'connect' this set to the Add() function and create an additional set meant for the Subtract() method and add this method in the same test class, resulting in one file called CalculatorTest.java?

Answer 1

This answer is similar to Tarek's one (the parametrized part), although I think it is a bit more extensible. Also solves your problem and you won't have failed tests if everything is correct:

@RunWith(Parameterized.class)
public class CalculatorTest {
    enum Type {SUBSTRACT, ADD};
    @Parameters
    public static Collection<Object[]> data(){
        return Arrays.asList(new Object[][] {
          {Type.SUBSTRACT, 3.0, 2.0, 1.0},
          {Type.ADD, 23.0, 5.0, 28.0}
        });
    }

    private Type type;
    private Double a, b, expected;

    public CalculatorTest(Type type, Double a, Double b, Double expected){
        this.type = type;
        this.a=a; this.b=b; this.expected=expected;
    }

    @Test
    public void testAdd(){
        Assume.assumeTrue(type == Type.ADD);
        assertEquals(expected, Calculator.add(a, b));
    }

    @Test
    public void testSubstract(){
        Assume.assumeTrue(type == Type.SUBSTRACT);
        assertEquals(expected, Calculator.substract(a, b));
    }
}