Why are these tests failing when my function is run?

My assignment is: Given an array create a function that modifies the data. All of the tests pass except for a couple. I've narrowed it down and it seems to be a couple of my if statements. For example the two tests that fail are below. I've ran tests myself and nor the artist or tracks are being manipulated.

After updateRecords(2548, "artist", ""), artist should not be set After updateRecords(2548, "tracks", ""), tracks should not be set

ASSIGNMENT:

"You are given a JSON object representing a part of your musical album collection. Each album has several properties and a unique id number as its key. Not all albums have complete information.

Write a function which takes an album's id (like 2548), a property prop (like "artist" or "tracks"), and a value (like "Addicted to Love") to modify the data in this collection.

If prop isn't "tracks" and value isn't empty (""), update or set the value for that record album's property.

Your function must always return the entire collection object.

There are several rules for handling incomplete data:

If prop is "tracks" but the album doesn't have a "tracks" property, create an empty array before adding the new value to the album's corresponding property.

If prop is "tracks" and value isn't empty (""), push the value onto the end of the album's existing tracks array.

If value is empty (""), delete the given prop property from the album.

Hints Use bracket notation when accessing object properties with variables.

Push is an array method you can read about on Mozilla Developer Network.

You may refer back to Manipulating Complex Objects Introducing JavaScript Object Notation (JSON) for a refresher."

// Setup
var collection = {
    "2548": {
      "album": "Slippery When Wet",
      "artist": "Bon Jovi",
      "tracks": [ 
        "Let It Rock", 
        "You Give Love a Bad Name" 
      ]
    },
    "2468": {
      "album": "1999",
      "artist": "Prince",
      "tracks": [ 
        "1999", 
        "Little Red Corvette" 
      ]
    },
    "1245": {
      "artist": "Robert Palmer",
      "tracks": [ ]
    },
    "5439": {
      "album": "ABBA Gold"
    }
};
// Keep a copy of the collection for tests
var collectionCopy = JSON.parse(JSON.stringify(collection));

// Only change code below this line
function updateRecords(id, prop, value) {

  var eval_track_prop = collection[id].hasOwnProperty("tracks");

  if(prop !== "tracks" && value !== ""){
    //update value for artist
    collection[id][prop] = value;
  } else if(prop === "tracks" && eval_track_prop === false){
    //Create 'tracks' property giving value empty array to store new tracks
    collection[id][prop] = [];
    //Push new track into the array
    collection[id][prop].push(value);
  } else if(prop === "tracks" && value !== ""){
    //Give property 'tracks' a new value
    collection[id][prop].push(value);
  } else {
    // delete the property and it's value
    delete collection[id].prop;
  }

  return collection;
};

// Alter values below to test your code
updateRecords(5439, "artist", "ABBA");