Null values in CSV Scenario Outline

Question

I have this scenario which I am reading a CSV file for Example values, and load them into my input JSON:

Scenario Outline:
   * def inputJson = karate.read('../karate/data/sample.json')
   * print "Input JSON is: " + karate.pretty(inputJson)

   Examples:
   |read('classpath:karate/data/testData.csv')|

In my sample.json:

{
  "testField" : "#(testField)"
}

And in my testData.csv:

testField,a,b,c,...
null,,,...

When I print out inputJson, the value null of testField is read as a string "null".

I also tried replacing the value as empty, as well as using testField! in my CSV header, but none of them loads the null value properly as null.

Any advice to achieve this?

Thank you in advance.