@Test
    public void noSchemaToJson() {
        Map<String, Boolean> props = Collections.singletonMap("schemas.enable", false);
        converter.configure(props, true);
        JsonNode converted = parse(converter.fromConnectData(TOPIC, null, true));
        assertTrue(converted.isBoolean());
        assertTrue(converted.booleanValue());
    }
When schemas are disabled, fields are mapped to Connect maps.
connect/json/src/test/java/org/apache/kafka/connect/json/JsonConverterTest.java