Using AJV in Postman seems to ignore nesting/children - validation

Question

I'm trying to validate JSON response messages according to schema.
But as soon as an attribute has the type "array" or "object", AJV seems to ignore them and does not see the nested attribute within that object or array.
I started trying to break up the schema into multiple smaller ones so all objects/arrays are covered, but this is a tedious task and I'm hoping I'm just using AJV incorrectly.
Example schema (simplified):
{
"type": "object",
"required": [
"MainThing"
],
"properties": {
"MainThing": {
"type": "string",
"description": "Some kind of string.",
"example": "This is some kind of string."
},
"NestedThing": {
"type": "object",
"required": [
"NestedAttribute"
],
"properties": {
"NestedAttribute": {
"type": "String",
"description": "A nested string.",
"example": "This is a nested string"
}
}
}
}
}
If I change the NestedAttribute to an Integer instead of a String, the schema validation in Postman will tell me the response is valid against the schema. While it's not, because the response will contain a NestedAttribute which is a String value.
The following response would be deemed valid, while it's not:
{
"MainThing": "The main thing",
"NestedThing": {
"NestedAttribute": 12345
}
}
My Postman testcode:
var Ajv = require('ajv'),
ajv = new Ajv({logger: console}),
schema = JSON.parse(pm.variables.get("THIS_IS_MY_AWESOME_SCHEMA"));
pm.test('My schema is valid', function() {
var data = pm.response.json();
pm.expect(ajv.validate(schema, data)).to.be.true;
});
If anyone can point me in the right direction, that would be greatly appreciated!