捕获块的 Junit 测试在捕获后不抛出任何异常

Question

I have to write Junit test for the catch block. But I am not able to identify what should I assert here. Since the func() is only catching the exception and not throwing anything I cannot assert using Assertions.assertThatExceptionOfType(). I am new to Junit testing so cannot think of anything else. Any possible way to test the type of exception received by catch block.

Method

public void func() {
    try {
        int x = solve();
    } catch(Exception1 e) {
        log.warn("error", e);
    } catch(Exception2 e) {
        log.warn("error", e);
    }
}

private int solve() throws ExceptionName {
    //do something...
    throws new Exception("error occured");
    ...
}

Answer 1

You can change the visibility of solve() method and test it with all exception cases. For example change it to default

int solve() throws ExceptionName {

Put tests in the same package as class with this method so that it could be access from test.

UPDATE

The best way would be to change the code to be more testable as it was shown above. In order to not change the code you can use the way from this answer . It can be tricky. With Mockito and PowerMockito you can control when Exception1 or Exception2 are creating. Based on this you will know which catch statement was executed.

In test code it could be like this:

@RunWith(PowerMockRunner.class)
@PrepareForTest({ Exception1.class, Exception2.class, MyClass.class })
public class TestClass {

    @Before
    public void setup() {
        Exception1 cutMock = Mockito.mock(Exception1.class);
        PowerMockito.whenNew(Exception1.class)
                .withArguments(Matchers.anyString())
                .thenReturn(cutMock);
    }

    @Test
    public void testMethod() {
        // prepare
        MyClasss myClass = new MyClass();

        // execute
        myClass.func();

        // checks if the constructor has been called once and with the expected argument values:
        String value = "abc";
        PowerMockito.verifyNew(Exception1.class).withArguments(value);
    }
}

Answer 2

I have to write Junit test for the catch block. But I am not able to identify what should I assert here. Since the func() is only catching the exception and not throwing anything I cannot assert using Assertions.assertThatExceptionOfType(). I am new to Junit testing so cannot think of anything else. Any possible way to test the type of exception received by catch block.

Method

public void func() {
    try {
        int x = solve();
    } catch(Exception1 e) {
        log.warn("error", e);
    } catch(Exception2 e) {
        log.warn("error", e);
    }
}

private int solve() throws ExceptionName {
    //do something...
    throws new Exception("error occured");
    ...
}