@Test
public void rejectConnectionWithIllFormedTrustedCertificates() {

    final Connection connection = createConnection(CONNECTION_ID).toBuilder()
            .trustedCertificates("Wurst")
            .build();
    final ConnectionValidator underTest = getConnectionValidator();
    assertThatExceptionOfType(ConnectionConfigurationInvalidException.class)
            .isThrownBy(() -> underTest.validate(connection, DittoHeaders.empty(), actorSystem));
}