jmeter: evaluate the values of JSON values

Question

I am trying to test my API response using JSON assertion in JMeter, but couldn't find out on how to achieve it. The API returns 2 values, and I need to check if the difference between these two value are consistent

API response:

{
  "start": "12759898",
  "end": "12759907"
}

I've tried like the above, but it seems to be wrong, as its a JSONPath variable. Could anyone guide on how to evaluate these values? is it possible to achieve this?

Answer 1

It looks like a job for JSR223 Assertion

1. Add JSR223 Assertion as a child of the request which returns the above JSON

2. Put the following code into "Script" area:

   def response = new groovy.json.JsonSlurper().parse(prev.getResponseData())
   def start = response.start as long
   def end = response.end as long
   def delta = end - start
   
   if (delta != 10) {
       AssertionResult.setFailure(true)
       AssertionResult.setFailureMessage('Expected: 10, got: ' + delta)
   }
   

   If the difference between start and end will not be equal to 10 - the request will be marked as failed.

   

More information:

• Groovy: Parsing and producing JSON
• Scripting JMeter Assertions in Groovy - A Tutorial