Testing JSON Data

Updated: June 14, 2024

The Nuxeo Platform offers a utility object to test JSON data: It is provided by nuxeo-core-io test-jar.

Maven dependency

<!-- JSON marshallers tests -->

Testing a Simple Marshaller

Let's test the following marshaller:

Product Java-to-JSON marshaller

@Setup(mode = Instantiations.SINGLETON, priority = Priorities.REFERENCE)
public class ProductJsonWriter extends AbstractJsonWriter<Product> {
    public void write(Product product, JsonGenerator jg) throws IOException {
        jg.writeNumberField("ref", product.getReference());
        jg.writeStringField("desc", product.getDescription());

The test looks like:

ProductJsonWriter test

public class ProductJsonWriterTest extends AbstractJsonWriterTest.Local<ProductJsonWriter, Product> {

    public ProductJsonWriterTest() {
        super(ProductJsonWriter.class, Product.class);

    public void test() throws Exception {
        Product product = new Product(123, "a description");
        JsonAssert json = jsonAssert(product);


Each line makes an assertion on the provided JSON. Each assertion returns either the current JsonAssert (json.isObject().properties(2)) or a new JsonAssert based on the referenced data (json.**has("reference")**.isEquals(product.getReference())).

If your marshaller uses other marshallers, don't forget to load the corresponding contribution using @Deploy or @LocalDeploy.

Testing an Enricher

If you wrote an enricher for DocumentModel, the tested object should be DocumentModel. In that case, don't forget to load the contribution which contains your enricher registering.

public class SomeEnricherTest extends AbstractJsonWriterTest.Local<DocumentModelJsonWriter, DocumentModel> {

    public ProductJsonWriterTest() {
        super(DocumentModelJsonWriter.class, DocumentModel.class);

    public void test() throws Exception {
        DocumentModel doc = ...;
        RenderingContext ctx = CtxBuilder.enrichDoc("someEnricher").get();
        JsonAssert json = jsonAssert(doc, ctx);
        json = json.has("contextParameters.someEnricher");
        // make assertion on the enricher here


Testing Any JSON Data

You can also use JsonAssert to test the result of your services.

public class SomeJsonTest {

    public void test() throws Exception {
        String jsonString = ...; // get JSON from somewhere
        JsonAssert json = JsonAssert.on(jsonString);
        // make assertion on the json here


Tips and Tricks

Getting the JSON

JsonAssert provides the ability to get the json at any level.

JSON to test

  "field1": { "field2": "hi!" },
  "field3": "hello"

JsonAssert json = ...;
System.out.println( json.toString() );
// will print the whole JSON
System.out.println( json.has("field1.field2").toString() );
// will print "hi!" - be careful, the quotes are keeped, that's the real JSON

Quickly Testing Deep Data

JsonAssert provides the ability to use JSON path.

JSON to test

  "field1": {
    "field2": [ {
        "field3": "myDataShouldBeHere"
    } ]


Quickly Testing Array Values

JsonAssert provides the ability to test array values.

JSON to test

  "field1": [ "A should be here", "B should be here", "C should be here twice", "C should be here twice" ]

json.has("field1").contains("A should be here", "B should be here", "C should be here twice", "C should be here twice");

Quickly Testing Complex Structure

JsonAssert provides the ability to test the value of a field for multiple object in an array.

JSON to test

  "field1": [
    { "field2": "A is here" },
    { "field2": "B is here twice" },
    { "field2": "B is here twice" }

json.childrenContains("field1.field2", "A is here", "B is here twice", "B is here twice");

JsonAssert.childrenContains can cross over multiple arrays and objects.