Karate framework retry until not working as expect

Question

I'm using Karate framework with JUnit.

Using this feature:

Given path 'save_token'
And request
"""
{
  "token": "test_token"
}
"""
And retry until response.tokens ==
"""
[
    "test_token"
]
"""
When method POST

I'm having this exception:

java.lang.ArrayIndexOutOfBoundsException: 1
    at com.intuit.karate.core.MethodMatch.convertArgs(MethodMatch.java:60)
    at com.intuit.karate.core.Engine.executeStep(Engine.java:141)
    at com.intuit.karate.core.ScenarioExecutionUnit.execute(ScenarioExecutionUnit.java:171)

When response.tokens list is empty:

{
    "tokens": []
}

I don't understand why == does not work in this case (it should return false, and keep retrying).

Thanks in advance!

Answer 1

The retry until expression has to be pure JavaScript and the special Karate match keywords such as contains are not supported, and you can't do a "deep equals" like how you are trying, as that also is not possible in JS.

So if your response is { "tokens": [ "value1" ] }, you can do this:

And retry until response.tokens.contains('value1')

Or:

And retry until response.tokens[0] == 'value1'

To experiment, you can try expressions like this:

* def response = { "tokens": [ "value1" ] }
* assert response.tokens.contains('value1')

At run time, you can use JS to take care of conditions when the response is not yet ready while polling:

And retry until response.tokens && response.tokens.length

EDIT: actually a more elegant way to do the above is shown below, because karate.get() gracefully handles a JS or JsonPath evaluation failure and returns null:

And retry until karate.get('response.tokens.length')

Or if you are dealing with XML, you can use the karate.xmlPath() API:

And retry until karate.xmlPath(response, '//result') == 5

And if you really want to use the power of Karate's match syntax, you can use the JS API:

And retry until karate.match(response, { tokens: '##[_ > 0]' }).pass

Note that if you have more complex logic, you can always wrap it into a re-usable function:

* def isValid = function(x){ return karate.match(x, { tokens: '##[_ > 0]' }).pass }
# ...
And retry until isValid(response)

Finally if none of the above works, you can always switch to a custom polling routine: polling.feature