Add tests for _TypedArray_ constructors

[leobalter]

No description provided.

[jugglinmike]

This is actually step 10 (the danger of tracking a moving target)

[jugglinmike]

Hey Leo!

I've left some specific notes as in-line comments on this pull request, but I
also had some ideas that don't belong to any specific line:

• The file naming scheme is a little inconsistent. Some names are prefixed with
  descriptions of the constructor under test, but others begin with a
  description of the behavior. To make discovery easier for others, I think we
  should choose one pattern and stick with it. My strong preference is to use
  the constructor as a prefix (since it mimics the general pattern of the rest
  of Test262's hierarchy), but I'd be open to arguments for the latter.
  Consistency is the important thing.

• By testing against maximum/minimum values across all typed arrays, the precision of many of these tests is degraded. For instance, following code (adapted from buffer-argument-excessive-offset-throws.js):

  var buffer = new ArrayBuffer(8);
  
  testWithTypedArrayConstructors(function(TA) {
    assert.throws(RangeError, function() {
      new TA(buffer, 16);
    });
  });

  Triggers the error by invoking Int8Array with an offset of 16, even though
  for that constructor and that buffer, an offset of 9 would prove the intended
  behavior with greater precision.

  I would recommend calculating edge cases using TA.BYTES_PER_ELEMENT in
  order to produce more fine-grained assertions. For instance:

  testWithTypedArrayConstructors(function(TA) {
    var buffer = new ArrayBuffer(TA.BYTES_PER_ELEMENT);
    assert.throws(RangeError, function() {
      new TA(buffer, 2 * TA.BYTES_PER_ELEMENT);
    });
  });

  Although calculated values aren't as immediately readable as literals, the
  intent of the test is much more clear when the bounds are derived from a
  formula.

• Some ideas for additional tests:

  • new TA(-0) to verify that SameValueZero (and not SameValue) is being used
    internally
  • Asserting the numeric order of traversal across properties in new TA(arrayLike)
  • Tests for the CloneArrayBuffer internal operation (it's not currently
    covered, as far as I can tell)

[leobalter]

e74fbbb and ed387f2 covers the inline feedback. I'm working on the remaining.

[leobalter]

Tests for the CloneArrayBuffer internal operation (it's not currently covered, as far as I can tell)

They already are, at least they're easier to find after the renaming. typedarray-arg-same-ctor-*

new TA(-0) to verify that SameValueZero (and not SameValue) is being used internally

that's a good one!

Asserting the numeric order of traversal across properties in new TA(arrayLike)

It might be covered on some of the object-arg-* files.

The file naming scheme is a little inconsistent

I hope you like it now. I have to say it was way easier for me to browser the files after this change.

I would recommend calculating edge cases using TA.BYTES_PER_ELEMENT in order to produce more fine-grained assertions

Maybe I should still improve it, but I got some changes regarding this.

---

Thanks for the review, @jugglinmike! It's ready for another (final?) round.

[anba]

The negative zero tests is already covered in https://github.com/tc39/test262/blob/master/test/built-ins/TypedArray/negative-zero-byteoffset.js

[leobalter]

@anba you're right, I was trying to find them on the TypedArrays folder. I'm removing this last commit.

[anba]

Please feel free to move the file into the TypedArrays folder. IIRC I've added that test before the ES2016 typed array constructor changes.

[leobalter]

@anba done at 75952be

I changed the filename to match the other files.

[goyakin]

Thanks @leobalter