[import-bytes] add initial tests for import bytes proposal

[styfle]

• Closes Test plan for import bytes #4647

[ljharb]

there should be some kind of assertion that it's immutable (not sure what that'd look like tho)

same throughout

[styfle]

The lines below are checking for immutable (asserts that an error is thrown on resize and also on transfer)

assert.throws(TypeError, function() {
  value.buffer.resize(0);
});

assert.throws(TypeError, function() {
  value.buffer.transfer();
});

Let me know if there is a better way to check for immutability.

[anba]

Directly call the immutable accessor property https://tc39.es/proposal-immutable-arraybuffer/#sec-get-arraybuffer.prototype.immutable ?

[styfle]

Interesting. I don't see any existing tests for ArrayBuffer.prototype.immutable.

I was basing this new test on the existing tests here:

test262/test/built-ins/ArrayBuffer/prototype/transfer/this-is-immutable-arraybuffer.js

Lines 27 to 30 in 3fd4ec2

	var ab = (new ArrayBuffer(4)).transferToImmutable();
	assert.throws(TypeError, function() {
	ab.transfer();
	});

test262/test/built-ins/ArrayBuffer/prototype/resize/this-is-immutable-arraybuffer-object.js

Lines 20 to 23 in 3fd4ec2

	var ab = (new ArrayBuffer(4)).transferToImmutable();
	assert.throws(TypeError, function() {
	ab.resize(0);
	});

[styfle]

I went ahead and added the new assertion in cafcddc

[bakkot]

Interesting. I don't see any existing tests for ArrayBuffer.prototype.immutable.

Still in PR, alas.

[ptomato]

Note, the empty file is failing because fixture files need to contain the string _FIXTURE and these have a dash where they should have an underscore: https://github.com/tc39/test262/blob/main/INTERPRETING.md#modules

[styfle]

@ptomato Thanks! I updated the fixtures to use underscores and that solved the Test262File: missing "contents" error.

However, I ran into another error.

  File "/home/runner/work/test262/test262/tools/generation/lib/test.py", line 29, in load
    self.source = handle.read()
                  ~~~~~~~~~~~^^
  File "<frozen codecs>", line 325, in decode
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x89 in position 0: invalid start byte

So I pushed some changes to the python code to ignore binary files.

I see there are still a few engines on circleci that are failing. Please let me know how to proceed, thanks!

[ptomato]

@styfle instead of hardcoding binary extensions I think it'd be better to just skip cleaning any files with _FIXTURE in the name? Would that work for you?

The CI jobs are timing out because they are detecting hundreds of tests as different in this PR than from main. Probably if you rebase on the latest state of the main branch, that'll go away.

[styfle]

@ptomato Thanks! I rebased on main and force pushed. That seemed to fix CI ✅

I also applied your suggestion to skip files with _FIXTURE in 7d42a35.

Let me know how that looks, thanks!