Expected body Content-Type is application/json; charset=utf-8 but body is not a parseable JSON

Hello. I got from the Dredd test failed report because he could not parse the JSON but I think the response is correct and contains parseable JSON body. I tried to validate response data with http://jsonlint.com/ and it passed. If I try call the API method by the Postman I get also valid JSON, so why Dredd can’t parse it?

Full Dredd report:

> dredd

info: Configuration dredd.yml found, ignoring other arguments.
info: Using apiary reporter.
info: Starting server with command: node server.js
info: Waiting 3 seconds for server command to start...
info: Beginning Dredd testing...
info: Found Hookfiles: tests/dreddhooks.js
skip: GET /api/products/product
fail: POST /api/products/product duration: 150ms
~~~other skipped tests~~~ 
skip: GET /api/settings
info: Displaying failed tests...
fail: POST /api/products/product duration: 150ms
fail: body: Can't validate. Expected body Content-Type is application/json; charset=utf-8 but body is not a parseable JSON: Parse error on line 1:

^
Expecting 'STRING', 'NUMBER', 'NULL', 'TRUE', 'FALSE', '{', '[', got 'EOF'

request: 
body: 
{
  "name": "DREDD TEST | Lamborghini Huracan",
  "subheading": "DREDD TEST | Supersport car all wheel drive, engine 5.2L V10",
  "description": "DREDD TEST | The Lamborghini Huracán is a sports car built by Lamborghini that replaces Lamborghini's sales leader and most produced car, the Gallardo.",
  "vendor_id": 1,
  "price_sale": 300000,
  "price_regular": 320000,
  "amount_available": 1616,
  "image_width": 2,
  "image_height": 1,
  "priority": 2,
  "publish_status": "active",
  "category_id": "business"
}
headers: 
    Content-Type: application/json
    User-Agent: Dredd/1.0.10 (Windows_NT 10.0.14295; x64)
    Content-Length: 466

uri: /api/products/product
method: POST


expected: 
headers: 
    Content-Type: application/json; charset=utf-8

body: 

statusCode: 201


actual: 
statusCode: 201
headers: 
    x-powered-by: Express
    content-type: application/json; charset=utf-8
    content-length: 638
    etag: W/"27e-ESB3wpmhXJgZSsrjly9wIw"
    set-cookie: connect.sid=s%3A4MLpXvSZSpKNhLyTXxXw8-gaZmcdUsYK.nrquq3V5bpw0dYzp4IbEfSZ1X7A7%2B%2BYVPBKkrhkPyC0; Path=/; HttpOnly
    date: Sat, 23 Apr 2016 21:24:56 GMT
    connection: close

body: 
{"product_id":32,"priority":2,"publish_status":"active","name":"DREDD TEST | Lamborghini Huracan","subheading":"DREDD TEST | Supersport car all wheel drive, engine 5.2L V10","description":"DREDD TEST | The Lamborghini Huracán is a sports car built by Lamborghini that replaces Lamborghini's sales leader and most produced car, the Gallardo.","price_sale":300000,"price_regular":320000,"amount_available":0,"image_width":2,"image_height":1,"timestamp_create":"2016-04-23T21:24:56.000Z","timestamp_lastedit":"2016-04-23T21:24:56.000Z","vendor_id":1}



complete: 0 passing, 1 failing, 0 errors, 13 skipped, 14 total
complete: Tests took 1432ms
POST /api/products/product 201 105.337 ms - 638
complete: See results in Apiary at: https://app.apiary.io/~~~CENSORED~~~/tests/run/e79bd8df-08e9-43c6-a97a-829b27171222
info: Sending SIGTERM to the backend server
info: Backend server was killed

The server response is made by Express:

connection.query(sql_query, function (err, rows, fields) {
  (!err) {
    ...
    res.status(201).json(rows[0]);
    ...
  }
});

Apiblueprint file:

...

### Save New Product Item [POST /api/products/product]
+ Attributes (NewlyCreatedProductItem)
+ Request (application/json)
+ Response 201 (application/json; charset=utf-8)

...

# Data Structures

## NewlyCreatedProductItem (object)
+ name: Lamborghini Huracan (string, required)
+ subheading: Supersport car all wheel drive, engine 5.2L V10 (string, required)
+ description: The Lamborghini Huracán is a sports car built by Lamborghini that replaces Lamborghini's sales leader and most produced car, the Gallardo. (string, required)
+ vendor_id: 1 (number, required)
+ price_sale: 300000 (number, required)
+ price_regular: 320000 (number)
+ amount_available: 1616 (number, required)
+ image_width: 2 (number, required)
+ image_height: 1 (number, required)
+ priority: 2 (number, required)
+ publish_status: active (string, required)
+ category_id: business (string, required)

...

Dreddhooks file:

before("Products > Product Item > Save New Product Item", function (transaction) {
    /* Add DREDD identificators to the new project data files */
    var newProduct = JSON.parse(transaction.request.body);
    var prefixText = 'DREDD TEST | ';
    newProduct.name = prefixText + newProduct.name;
    newProduct.subheading = prefixText + newProduct.subheading;
    newProduct.description = prefixText + newProduct.description;

    newProduct = JSON.stringify(newProduct);
    transaction.request.body = newProduct;
});

System configuration:

NodeJS: v5.7.0
NPM: v3.6.0
Dredd: v1.0.10
Express.JS: v4.13.1

[MikeRalphson]

• Minimal valid swagger definition
• Failing test
• Passing test

The only change required to make the test pass is the following diff to the swagger definition:

--- contract/min.json   2017-10-18 08:41:09.693730500 +0100
+++ contract/minplus.json       2017-10-18 08:46:48.036825400 +0100
@@ -27,7 +27,8 @@
                 ],
                 "responses": {
                     "200": {
-                        "description": "default"
+                        "description": "default",
+                        "schema": {}
                     }
                 }
             }

[honzajavorek]

@MikeRalphson Please do if you can - I’m author of way too many issues on this repo already 😄