ProblemCollector collector2 = ProblemCollectorFactory.newInstance(Collections.singletonList(problem));

        assertNotSame(collector1, collector2);
        assertEquals(0, collector1.getProblems().size());
        assertEquals(1, collector2.getProblems().size());
    }

    @Test
    void testAddProblem() {
        ProblemCollector collector = ProblemCollectorFactory.newInstance(null);
        collector.setSource("pom.xml");

                getProblems(problem.getSeverity()).add(problem);
                return true;
            }
            return false;
        }

        @Override
        public Stream<P> problems(BuilderProblem.Severity severity) {
            requireNonNull(severity, "severity");
            return getProblems(severity).stream();
        }