POSTMAN - Test failure false to be truthy - api

Question

As a beginner I have few questions. I am using the Get request, which would populate json below.
https://reqres.in/api/users
{
"total": 12,
"total_pages": 4,
"data": [{
"id": 1,
"first_name": "George",
"last_name": "Bluth",
"avatar": "https://s3.amazonaws.com/uifaces/faces/twitter/calebogden/128.jpg"
}]
}
for the 2 tests below while the 1st one passes the 2nd test fails with the message:
AssertionError: expected false to be truthy
//Verify Page number total is 12
var jsonData = JSON.parse(responseBody);
tests["Checking total page number-Manual"] = jsonData.total === 12;
//verify is exists and is 1
var jsonData = JSON.parse(responseBody);
tests["Checking ID exists and is 1"] = jsonData.id === 1;
Question 1:
A github post that I found says there may be an error and suggests to use
the new pm.* equivalent instead. However I do not see any difference between the 1st and the 2nd. So why does the 2nd test fail?
Question 2:
Is it possible to write test to verify that for ID:1 the firstname is George?
Thanks in advance for your time.

Answer 1

The reason that your 2nd test fails is because data is an array and in this case you must access the first element. You would want to do something like this (new syntax):
pm.test("Verify id is equal to 1", function() {
var jsonData = pm.response.json();
pm.expect(jsonData.data[0].id).to.equal(1);
});
Similarly for testing first name is George:
pm.test("Verify id is equal to 1", function() {
var jsonData = pm.response.json();
pm.expect(jsonData.data[0].first_name).to.equal("George");
});
If you always expect it to only be a single element in the array then you're safe to use index 0 i.e. data[0]. However if you expect there to be more elements in the data array then you would have to iterate through them to look for the correct element.
Here's a good reference for the API:
https://learning.getpostman.com/docs/postman/scripts/postman_sandbox_api_reference/