@Test
public void testInvalidMatcherThrowsException() {

    final Source source = newSourceBuilder()
            .enforcement(ConnectivityModelFactory.newEnforcement(
                    "{{ header:device_id }}", "{{ header:ditto }}"))
            .build();
    Assertions.assertThatExceptionOfType(ConnectionConfigurationInvalidException.class)
            .isThrownBy(() -> UNDER_TEST.validateSource(source, DittoHeaders.empty(), () -> "testSource"))
            .withCauseInstanceOf(UnresolvedPlaceholderException.class);
}