Postman: How to check whether the field is returning null in the Postman automation

Question

I have tried with \"!== null\", but it is returning PASS even when the field is returning 0 or \"\".

Answer 1

How about:

var jsonData = JSON.parse(responseBody);

tests["Item is not null"] = 
    jsonData.item !== null && 
    jsonData.item !== ' ' && 
    jsonData.item !== 0;

Answer 2

I faced similar issue. But checking it in following way worked for me

tests["Item is not null"] = 
    jsonData.item !== undefined;

Answer 3

Did you try

pm.expect(response.your_field).to.eql(null);

?

Answer 4

You gotta place the + [i] after the function you gonna validate on the tests[] so only it will return valid statements on each array. For example,

function checkIsNull() {
    var items = json.data.pois.items
    var PlaceIdIsNull = true;
    var subTypeExtraIsNull = true;
    var websiteIsNull = true;

    for (var i = 0; i < items.length; i++) {
    if (items[i].placeId !== null) {
        PlaceIdIsNull = false;
    }
    if (items[i].subTypeExtra !== null) {
        subTypeExtraIsNull = false;
    }
    if (items[i].website === null) {
        websiteIsNull = false;
        tests['website is null only happened on these arrays' + [i]] = true;
        }
        tests['Place ID is null '] = PlaceIdIsNull
        tests['subTypeExtra is null '] = subTypeExtraIsNull
}
}
       checkIsNull();

Result:

---

PASS Place ID is null

PASS subTypeExtra is null

Answer 5

If you are checking the Id of the first item returned in a list, you could use not.equal(null):

pm.expect(pm.response.json().value[0].Id).not.equal(null);

Note that the word "equal" is fully spelled out, although the shortened "eql" does work.

Answer 6

Postman doesn't reference non-existent paths as null, but as undefined.

pm.expect(JsonResponse.FAKE.PATH).not.eql(undefined);

This test should fail, as this fake json path is actually undefined.