cloudqa

JSON Schema Validator

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Siddartha
·

2 min read

We use json for API responses, and the task is to validate the response schema with previous release to find regression if any.

So there was a bug in the system where a json was responding as below 

{
data: [
20,30,0,0,0,0,0]
}

instead of 

{
data: [
20,30]
}

Automation failed to catch as the validation was only the first two values.

So, the better way to was to add schema validator.

This post contains the details of some help links which help to develop a suite.

Schema validators -> [Array reference guide] (json-schema.org/understanding-json-schema/r..)

For validating the length of array, json schema validator provides below parameters. 

{
  "type": "array",
  "minItems": 2,
  "maxItems": 3
}

If you are looking for something other than array, then information is below: Schema all details

Tools to create schema

  1. QuickType
  2. One I used to create schema

this too doesn't provide minItems maxItems, these should be added manually as per need.

Schema validator used to verify: Schema validator

The issue was successfully found by the tool:

Found 1 error(s) Message: Array item count 22 exceeds maximum count of 2. Schema path:

#/properties/data/properties/samples/items/0/properties/data/maxItems

Now next step is to do the above things programmatically .

Adding the code snippet which was used to write script

import requests
import json
import jsonschema
from jsonschema import validate


failedtests = []

def validateJson(jsonData,schemaexpected,testcase):
    try:
        validate(instance=jsonData, schema=schemaexpected)
    except jsonschema.exceptions.ValidationError as err:
        print err

        global failedtests
        failedtests.append(testcase)
        return False
    return True

response = requests.get('https://sampleurl.com/users/v3/customers', headers=headers, params=params)
#print response.text
jsonData = json.loads(response.text)
validateJson(jsonData, jsonschema_of_customers, "check customers")
json