@Test
public void tryToGetInstanceWithUnknownSchemaVersions() {

    final int unknownVersionNumber = -1;
    final Collection<Integer> knownSchemaVersions =
            List.of(JsonSchemaVersion.V_1.toInt(), JsonSchemaVersion.V_2.toInt());
    final Collection<Integer> allSchemaVersions = new ArrayList<>(knownSchemaVersions);
    allSchemaVersions.add(unknownVersionNumber);
    final String configPath = "http." + HttpConfig.GatewayHttpConfigValue.SCHEMA_VERSIONS.getConfigPath();
    final Config config = ConfigFactory.parseMap(Maps.newHashMap(configPath, allSchemaVersions));
    assertThatExceptionOfType(DittoConfigError.class)
            .isThrownBy(() -> GatewayHttpConfig.of(config))
            .withMessage("Schema version <%s> is not supported!", unknownVersionNumber)
            .withNoCause();
}