{
 "data": [
    {
        "id": "123",
        "type": "something",
        "created": "1540952074",
        "test": [
            {
                "key1": "asd123",
                "key2": "166802"
            }
        ]
    },

pm.test('returns the correct parameters by type', () => {
for (i = 0; i < jsonData.data.length; i++) {
    if (jsonData.data[i].type === 'something') {
       // for (j = 0; j < jsonData.data.test.length; j++) {

            pm.expect(jsonData.data[i]).to.have.property('id');
            pm.expect(jsonData.data[i]).to.have.property('type');
            pm.expect(jsonData.data[i]).to.have.property('created');

      pm.expect(jsonData.data[i].test[0]).to.have.property('key1');
      pm.expect(jsonData.data[i].test[0]).to.have.property("key2");
        }

returns the correct parameters by type | TypeError: Cannot read property '0' of undefined

Object:{}
key1:"asd123"
key2:"166802"