CODEWITHSUNDEEP
javajunit4
Renata Chai
Renata Chai

Reputation: 66

How to test a constructor in Junit test?

How to test this Fraction constructor in Junit4 test case? Thank you!

public class Fraction {

    private int num;
    private int den;

    public Fraction(int num,int den){
        this.num=num;
        this.den=den;
        if(den==0){
            this.den=1;
            System.out.println("ERROR: DENOMINATOR CAN NOT BE 0");
            System.out.println("Now the fraction is changed to"+toString());
        }
    }
}

Upvotes: 0

Views: 6880

Answers (1)

Mureinik
Mureinik

Reputation: 312404

I'd run the constructor and then check the denominator holds the value you expect:

public class FractionTest() {
    private Fraction f;

    @Test
    public void testLegalConstruction() {
        f = new Fraction (4, 7);
        assertEquals ("wrong num", 4, f.getNum());
        assertEquals ("wrong den", 7, f.getDen());

    @Test
    public void testIlegalConstruction() {
        f = new Fraction (3, 0);
        assertEquals ("wrong num", 3, f.getNum());
        assertEquals ("wrong den", 1, f.getDen()); // Note the 1
}

Upvotes: 3

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