[FIXED] Assert a property from list object as null using Java 8

Issue

This is my mock response, where I need to assert a particular field (type) as null. It always throws me exception as

   java.lang.AssertionError: expected null, but was:<[null]>
    at org.junit.Assert.fail(Assert.java:88)
    at org.junit.Assert.failNotNull(Assert.java:755)
    at org.junit.Assert.assertNull(Assert.java:737)
    at org.junit.Assert.assertNull(Assert.java:747)

Mock response

{
"locations": [
 {
  "type": null,     
  "statusDt": "2018-08-15",
 
   }
  ]  
}

I'm doing assertion in the followig way

    assertNull(locationResponse.getLocations().stream().map(location -> location.getType()).collect(Collectors.toList()));

Solution

Seems like as a result of collect() operation you get a List that contains only one element null. Please try to get first element from that list

assertNull(locationResponse.getLocations().stream().map(location -> location.getType()).collect(Collectors.toList()).get(0));

Answered By - Ivan