Preserves the original order of elements when returning the duplicates

[ranjitshinde91]

Check List:

• Fixes assertThat(collection).doesNotHaveDuplicates() is not sorted, even if the collection is #3331
• Unit tests : YES
• Javadoc with a code example (on API only) : YES
• PR meets the contributing guidelines

Following the contributing guidelines will make it easier for us to review and accept your PR.

[Bananeweizen]

you can get rid of addedAddDuplicates entirely, if you make the second part of the if test !duplicatesInOriginalOrder.contains(element)

[ranjitshinde91]

For collection of array type e.g. newArrayList(array("Merry"), array("Frodo"), array("Merry")) TreeSet uses custom comparator to identify the duplicates. This is done by checking the deeply equals for two array( areEquals method). so identical arrays like array("Merry") are seen as duplicates by TreeSet.

since we don't have this comparator in LinkedHashSet, it will not be able to identify two arrays with same elements as duplicates.

[kulgan]

I might be missing a lot of context here, so ignore me if that is the case. Instead of introducing a private method, can this be done in the duplicatesFrom method instead, like replacing Lines 34 with a LinkedHashSet?

[ranjitshinde91]

earlier it was not possible but for option-2 (first duplicate first in response) implementation its possible.

I have made that change.

[Bananeweizen]

looks okay to me. I just don't understand why so many tests have been adapted. I would expect that those can remain as before, can't they?

[ranjitshinde91]

Tests are changed because order of duplicate elements in response is changed now.

e.g if the list has (6, -8, 6, 8) previous implementation with TreeSet + AbsoluteValueComparator would return (6, 8)
now with order preserved it returns (6, -8)

[joel-costigliola]

@ranjitshinde91 there are tests failing, can you look at them ?

[ranjitshinde91]

@joel-costigliola there were few formatting errors, fixed those.

[Bananeweizen]

looks good to me.

[kulgan]

Looks good to me

[joel-costigliola]

Integrated thanks @ranjitshinde91, @Bananeweizen and @kulgan !