[Not an issue] How to create schema to generate a JSON Array using Schema and transformers provided by DataFaker API in Java?

[amodmahajan2016]

Sorry to ask here but I am doubtful if I can get a solution on Stack overflow.

I am using DataFaker library to create schema for JSON Object and Array. Since the use of Format is deprecated, I am trying with Transformation Schemas. I tried examples given under the Format section of official documentation to create a schema for Json Array but wasn't successful. Example JSON Array -

[ { "firstName": "Oleta", "lastName": "Toy" }, { "firstName": "Gerard", "lastName": "Windler" } ]

[snuyanzin]

I tried examples given under the Format section of official documentation to create a schema for Json Array but wasn't successful.

could you please share the code to make the discussion more fruitful?

[erikpragt-connectid]

Hi @amodmahajan2016 ,

I think the documentation on this is a little out of date, apologies for that. I think something like this should work:

    @Test
    fun `generate json with custom field names`() {
        val faker = Faker()

        val schema: Schema<String, *> = Schema.of(
            field("firstName", Supplier { faker.name().firstName() }),
            field("lastName", Supplier { faker.name().lastName() })
        )

        val transformer = JsonTransformer.builder<String>().formattedAs(JSON_ARRAY).build()
        val json = transformer.generate(schema, 2)

        println(json)
    }

Alternatively, in Java:

package test;

import net.datafaker.Faker;
import net.datafaker.transformations.JsonTransformer;
import net.datafaker.transformations.Schema;
import org.junit.jupiter.api.Test;

import static net.datafaker.transformations.Field.field;
import static net.datafaker.transformations.JsonTransformer.JsonTransformerBuilder.FormattedAs.JSON_ARRAY;

public class MyTest {

    @Test
    public void test() {
        var faker = new Faker();

        Schema<String, String> schema =
                Schema.of(
                        field("firstName", () -> faker.name().firstName()),
                        field("lastName", () -> faker.name().lastName()));

        JsonTransformer<String> transformer = JsonTransformer.<String>builder().formattedAs(JSON_ARRAY).build();

        String json = transformer.generate(schema, 10);

        System.out.println(json);

    }
}

Hope this helps!

[amodmahajan2016]

Thanks, it worked. But how to create JSON Array at field level then? Something as below -

[
  {
    "firstName": "Oleta",
    "lastName": "Toy",
    "skills" : [{
      "lang": "some"
    },
    {
      "lang": "boo"
    }]
  }
]

Will "Format" be removed soon as that has more clear and easy syntax?

[snuyanzin]

But how to create JSON Array at field level then

just add compositeField to schema

    compositeField("skills", new Field[] {field("lang", () -> faker.nation().language())})

full code snippet

    @Test
    void test() {
        var faker = new Faker();

        Schema<String, String> schema =
            Schema.of(
                field("firstName", () -> faker.name().firstName()),
                field("lastName", () -> faker.name().lastName()),
                compositeField("skills", new Field[] {field("lang", () -> faker.nation().language())})
            );

        JsonTransformer<String> transformer = JsonTransformer.<String>builder().formattedAs(JSON_ARRAY).build();

        String json = transformer.generate(schema, 10);

        System.out.println(json);
    }

[snuyanzin]

Will "Format" be removed soon

it's already removed in main if we are talking about json

[amodmahajan2016]

compositeField is generating nested JSON Object as below. My requirement is to generate a key with JSON ARRAY value.

[
  {
    "Text": "Elicia",
    "Bool": false,
    "skills": {
      "lang": "Hindi"
    }
  },
  {
    "Text": "Sheldon",
    "Bool": false,
    "skills": {
      "lang": "Arabic"
    }
  }
]

I tried as below and it generates like "ints": [1, 2, 3]. I tried putting Fields instead of Integers but it is not working.
field("ints", () -> new Object[]{1, 2, 3})

[snuyanzin]

ok, in this case it will be a bit different

 void test() {
        var faker = new Faker();

        Schema<String, ?> schema =
            Schema.of(
                field("firstName", () -> faker.name().firstName()),
                field("lastName", () -> faker.name().lastName()),
                field("skills", () ->
                    List.of(compositeField(null,
                        new Field[]{field("lang", () -> faker.nation().language())})
                    )
                )
            );

        JsonTransformer<String> transformer = JsonTransformer.<String>builder().formattedAs(JSON_ARRAY).build();

        String json = transformer.generate(schema, 10);

        System.out.println(json);
    }

[amodmahajan2016]

It is giving output (not correct) as below which is similar to when I used new Object[] -

{
  "firstName": "Darryl",
  "lastName": "Champlin",
  "skills": [
    "net.datafaker.transformations.CompositeField@22101c80"
  ]
}

[snuyanzin]

for me it outputs

[
{"firstName": "Tiffiny", "lastName": "Casper", "skills": [{"lang": "Zulu"}]},
{"firstName": "Lorena", "lastName": "Dibbert", "skills": [{"lang": "Japanese"}]},
{"firstName": "Jamal", "lastName": "Dibbert", "skills": [{"lang": "Russian"}]},
{"firstName": "Mario", "lastName": "Prohaska", "skills": [{"lang": "Korean"}]},
{"firstName": "Agustina", "lastName": "Pfeffer", "skills": [{"lang": "Hakka"}]},
{"firstName": "Edra", "lastName": "Watsica", "skills": [{"lang": "English"}]},
{"firstName": "Clarice", "lastName": "Ryan", "skills": [{"lang": "Marathi"}]},
{"firstName": "Edra", "lastName": "Schneider", "skills": [{"lang": "Kazakh"}]},
{"firstName": "Marlyn", "lastName": "Luettgen", "skills": [{"lang": "Japanese"}]},
{"firstName": "Art", "lastName": "Wisozk", "skills": [{"lang": "Hindi"}]}
]

are you sure you are running exactly the same code as i put in comment above?

[amodmahajan2016]

Yes, exactly the same code. I am using 1.8.0

[snuyanzin]

ok i see,

I am using 1.8.0

that is probably the reason
the example I mentioned works after merge of this #693
that is only in main and will be a part of future releases

[amodmahajan2016]

ok i see,

I am using 1.8.0

that is probably the reason the example I mentioned works after merge of this #693 that is only in main and will be a part of future releases

Thanks @snuyanzin, @erikpragt-connectid. Waiting eagerly for the next release. This feature is really awesome and unfortunately many are aware of this. This will be great for API automation testing. I will post some blogs/videos on these concepts.

[hetzijzo]

I am using version 1.9.0 currently, but I experience the same behaviour as @amodmahajan2016. The #693 seems to be merged. What could be wrong? Has it been released yet?

[snuyanzin]

it's merged to 2.x (main branch)
it's not merged to 1.x branch
may be makes sense to merge to 1.x as well..

[hetzijzo]

Aha that makes sense. Also a merge into 1.x would be nice, since the 2.x is only available as SNAPSHOT version. I will make a remark in the original bug with a question if it can be merged into 1.x as well.

[bodiam]

Well, 2.0 is the future release, we will release a 2.0 version soon.

[snuyanzin]

merged to 1.x as 8ad4e56

[snuyanzin]

closing since it was merged to both 1.x and 2.x
also 2.0 has been released with this fix already