@Test (expected = SchemaValidationFailedException.class)
public void convertMapHavingNull() throws Exception {

    Schema schema = Schema.of(
            Schema.Field.of("a", Schema.Type.STRING),
            Schema.Field.of("b", Schema.Type.LONG));
    Map<String, Object> value = new HashMap<>();
    value.put("a", null);
    value.put("b", 1234);
    SchemaValueConverter.convertMap(schema, value);
}