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?

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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 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));
    }
}