if err != nil {
		// istioctl should keep going if it encounters new Envoy versions; ignore unknown types
		return &exprpb.Type{TypeKind: &exprpb.Type_Dyn{Dyn: &emptypb.Empty{}}}, nil
	}
	return legacyproto.MessageV1(mt.New().Interface()), nil

        collector.add(null, "MESSAGE1", -1, -1, null);

        Exception e2 = new Exception();
        collector.add(Severity.WARNING, null, 42, 127, e2);

        assertEquals(2, collector.getProblems().size());

        Problem p1 = collector.getProblems().get(0);
        assertEquals(Severity.ERROR, p1.getSeverity());
        assertEquals("MESSAGE1", p1.getMessage());

import static org.junit.jupiter.api.Assertions.assertEquals;

class ModelBuildingExceptionTest {

    @Test
    void testMessage() {
        DefaultModelProblem pb1 =
                new DefaultModelProblem("message1", ModelProblem.Severity.ERROR, null, "source", 0, 0, "modelId", null);
        DefaultModelProblem pb2 =
                new DefaultModelProblem("message2", ModelProblem.Severity.ERROR, null, "source", 0, 0, "modelId", null);

class ProblemCollectorFactoryTest {

    @Test
    void testNewInstance() {
        ProblemCollector collector1 = ProblemCollectorFactory.newInstance(null);

        Problem problem = new DefaultProblem("MESSAGE1", null, null, -1, -1, null);
        ProblemCollector collector2 = ProblemCollectorFactory.newInstance(Collections.singletonList(problem));

        assertNotSame(collector1, collector2);