How to write Junit for Interface default methods

Question

Please help in writing Junit for the interface default method.

public interface ABC {
    default List getSrc(DEF def, XYZ xyz) t         


        

Answer 1

You can either create a class that implements your interface or make your test implement it. The second one seems to be a shorter solution:

public class FunctionCallingTransactionTemplateTest implements FunctionCallingTransactionTemplate {
    private final Object object = Mockito.mock(Object.class);

    @Test
    public void should_invoke_function() throws Exception {
        // given
        when(object.toString()).thenReturn("salami");

        // when
        String result = functionCallingTransactionTemplate().execute((status) -> object.toString());

        // then
        assertThat(result).isEqualTo("salami");
    }
}