diff library eats last line if final newline is missing

[pdawyndt]

Seemingly, the diff library used by Dodona eats the last line of a test expected/generated pair if the final newline is missing in at least one of the two.

Example: submission 821685 (second testcase with expected/generated return value should have three lines, not two.

This is how the JSON for the test in this testcase looks like, when I locally run the submission.

"tests": [
    {
        "status": "wrong answer",
        "accepted": false,
        "expected": "1: 0\n2: 3\n3: 0",
        "data": {
            "channel": "return"
        },
        "generated": "1: 0\n2: 3\n3: 0\n",
        "messages": [
            {
                "description": "Error: returned string has spurious trailing newline",
                "format": "code"
            }
        ],
        "description": {
            "description": "<span class=\"label label-danger\" style=\"display: block;text-align:left;\">return</span>",
            "format": "html"
        }
    }
],

Original issue by @pdawyndt on Wed May 03 2017 at 16:21.
Closed by @charvp on Fri Nov 09 2018 at 08:09.

[ninewise]

It does indeed. I've created an issue with the gem.

> puts Diffy::Diff.new("1\n2", "1\n2\n").to_s
 1
-2
\ No newline at end of file
+2
 => nil
> puts Diffy::Diff.new("1\n2", "1\n2\n").to_s(:html)
<div class="diff">
  <ul>
    <li class="unchanged"><span>1</span></li>
  </ul>
</div>
 => nil

Original comment by @ninewise on Wed May 03 2017 at 16:52.