`should return an object with X property`

In this case, if this API call can return partial values (only some properties for example) then you need to test each case separately.  For example, if it only ever returns *all* the properties, then one test is fine.  In that test, you would check each property one by one using the assert library:

```javascript
var return = apiCall(); // Pseudocode for the logic that would execute the call

assert.equals( return.firstProperty, whateverItShouldBe);
assert.equals( return.secondProperty, whateverItShouldBe);
assert.equals( return.thirdProperty, whateverItShouldBe);
...etc
```

Otherwise, if this call might (correctly) return only some properties, you must isolate those possibilities for testing:

```javascript
it('should return firstProperty when SPECIFIC_CONDITION is met', function(){
  var return = apiCall(); // Pseudocode for the logic that would execute the call

  assert.equals( return.firstProperty, whateverItShouldBe);
});
it('should return secondProperty when ANOTHER_SPECIFIC_CONDITION is met', function(){
  var return = apiCall(); // Pseudocode for the logic that would execute the call

  assert.equals( return.secondProperty, whateverItShouldBe);
});
...etc
```

In this situation, remember that you may have to test to make sure the other properties AREN'T there!  

```javascript
it('should return firstProperty when SPECIFIC_CONDITION is met', function(){
  var return = apiCall(); // Pseudocode for the logic that would execute the call

  assert.equals( return.firstProperty, whateverItShouldBe);
  
  // Checks that secondProperty doesn't exist, as expected
  assert.equals( return.hasProperty( secondProperty ), false); /
});
...etc
```