@Test
    public void structSchemaIdentical() {
        Schema schema = SchemaBuilder.struct().field("field1", Schema.BOOLEAN_SCHEMA)
                                              .field("field2", Schema.STRING_SCHEMA)
                                              .field("field3", Schema.STRING_SCHEMA)
                                              .field("field4", Schema.BOOLEAN_SCHEMA).build();
        Schema inputSchema = SchemaBuilder.struct().field("field1", Schema.BOOLEAN_SCHEMA)
                                                   .field("field2", Schema.STRING_SCHEMA)
                                                   .field("field3", Schema.STRING_SCHEMA)
                                                   .field("field4", Schema.BOOLEAN_SCHEMA).build();
        Struct input = new Struct(inputSchema).put("field1", true).put("field2", "string2").put("field3", "string3").put("field4", false);
        assertStructSchemaEqual(schema, input);
    }
When schemas are disabled, fields are mapped to Connect maps.
connect/json/src/test/java/org/apache/kafka/connect/json/JsonConverterTest.java