CODEWITHSUNDEEP
javaunit-testingtestingjunitjunit4
David Àlvarez Tudela
David Àlvarez Tudela

Reputation: 421

Assert an Exception is Thrown in

I have this Junit test in my project

public class CalculatorBookingTest {

    private CalculatorBooking calculatorBooking;

    @Rule
    public ExpectedException expectedException = ExpectedException.none();

    @Before
    public void setUp() {
        calculatorBooking = new CalculatorBooking();
    }

    @Test
    public void shouldThrowAnException_When_InputIsNull() {
        calculatorBooking.calculate(null, null, 0, null);
        expectedException.expect(CalculationEngineException.class);
        expectedException.expectMessage("Error");
    }

}

but when I run the test, the Exception is Thrown but nevertheless the test fail

Upvotes: 0

Views: 56

Answers (3)

Ananthapadmanabhan
Ananthapadmanabhan

Reputation: 6216

You could do something like:

@Test(expected = CalculationEngineException.class)
public void shouldThrowAnException_When_InputIsNull() {
    calculatorBooking.calculate(null, null, 0, null);
}

From Junit doc :

The Test annotation supports two optional parameters. The first, expected, declares that a test method should throw an exception. If it doesn't throw an exception or if it throws a different exception than the one declared, the test fails.

Upvotes: 2

Stanislav Bashkyrtsev
Stanislav Bashkyrtsev

Reputation: 15308

You need to first tell JUnit that the method is expected to throw the exception. Then when it's thrown - it knows that the test passes. In your code you put expect() after the exception is thrown - so the execution doesn't even go that far. The right way:

@Test
public void shouldThrowAnException_When_InputIsNull() {
    expectedException.expect(CalculationEngineException.class);
    expectedException.expectMessage("Error");
    calculatorBooking.calculate(null, null, 0, null);
}

Upvotes: 0

Thiyagu
Thiyagu

Reputation: 17890

Place expectedException.expect before the call that will throw the exception.

@Test
public void shouldThrowAnException_When_InputIsNull() {
    expectedException.expect(CalculationEngineException.class);
    expectedException.expectMessage("Error");

    calculatorBooking.calculate(null, null, 0, null);

}

Upvotes: 0

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