Inconsistent test cases in the Hamming exercise

[HenryRLee]

In #1450, two tests cases are added to the Hamming exercise. If one of the argument is empty, it throws an exception with message "[left|right] strand must not be empty":

    {
      "description": "disallow left empty strand",
      "property": "distance",
      "input": {
        "strand1": "",
        "strand2": "G"
      },
      "expected": {"error": "left strand must not be empty"}
    },
    {
      "description": "disallow right empty strand",
      "property": "distance",
      "input": {
        "strand1": "G",
        "strand2": ""
      },
      "expected": {"error": "right strand must not be empty"}
    }

This message apparently contradicts with the first test case, where both arguments are empty, it runs without any exceptions:

    {
      "description": "empty strands",
      "property": "distance",
      "input": {
        "strand1": "",
        "strand2": ""
      },
      "expected": 0
    }

In my opinion, the error messages in these two cases, should be identical to the other different length exceptions, i.e. "left and right strands must be of equal length":

    {
      "description": "disallow first strand longer",
      "property": "distance",
      "input": {
        "strand1": "AATG",
        "strand2": "AAA"
      },
      "expected": {"error": "left and right strands must be of equal length"}
    }

A significant issue from the current test case is the exercise from the Java track, in order to pass all the test cases, I have to do:

// Only throw this if left strand is empty and right strand is not
if (leftStrand.isEmpty() && !rightStrand.isEmpty())
    throw new IllegalArgumentException("left strand must not be empty.");

// Only throw this if right strand is empty and left strand is not
if (rightStrand.isEmpty() && !leftStrand.isEmpty())
    throw new IllegalArgumentException("right strand must not be empty.");

if (leftStrand.length() != rightStrand.length())
    throw new IllegalArgumentException("leftStrand and rightStrand must be of equal length.");

where the condition and the message is not very consistent..

[TomPradat]

I'll work on this

[TomPradat]

It looks like this has been fixed since #1783

[petertseng]

rather, it was fixed in #1762