Test262

TC39 2019-07

Test262 Updates

@bocoup

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Since June

• Several tests for Intl.*
• Coverage for WeakRefs + FinalizationGroups
• More coverage for Class Fields (including private, etc)
• More coverage Numeric Separators and BigInt
• Coverage for StatementList!

Test262 Updates

@bocoup

bocoup.com

Missing a basic coverage

• Issue: https://github.com/tc39/test262/issues/2230
• {} /1/
• of / 2
• {1} 2

​

Test262 Updates

@bocoup

bocoup.com

StatementList

• function fn() {}() => { return 42; };
• {length:3000}['length']
• class C {}{x: 42}{}{}{}{}{}{}{}{}{}{}[];
• {}let a, b = 42;b;
• {1} 2;

https://github.com/tc39/test262/pull/2243

Test262 Updates

@bocoup

bocoup.com

Division

var instance = 60, of = 6, g = 2;

​

var notRegExp = instance/of/g;

​

assert.sameValue(notRegExp, 5);

​

https://github.com/tc39/test262/pull/2244

Test262 Updates

@bocoup

bocoup.com

WeakRefs

• Usage of a custom $262.gc() API in Test262 only.
• Problem: per specs, we can't mandate GC to collect refs.
• WeakRef/FinalizationGroup is already too loose, cleanup execution is also not guaranteed per GC execution.

Test262 Updates

@bocoup

bocoup.com

WeakRefs

• Usage of a custom $262.gc() API in Test262 only.
• Ideally, this would enforce an "effective" GC call

Test262 Updates

@bocoup

bocoup.com

WeakRefs

• If we can't have a GC hook ($262.gc()):
• We need to remove all the landed tests for WeakRef + FinalizationGroup relying on it.

Test262 Updates

@bocoup

bocoup.com

WeakRefs

• Tentative solution: Use custom hook $262.gc() to require collection?
• It can return a promise to wait for a event loop.
• Problems: It might not be possible/usable for JSC

Test262 Updates

@bocoup

bocoup.com

Numeric Separator + BigInt

• Shipped tests for Numeric Separator in BigInt literals!
• https://github.com/tc39/test262/pull/2252

Test262 Updates

@bocoup

bocoup.com

BigInt + NonOctal

• BigInt is disallowed in LegacyOctalIntegerLiteral
• It is currently allowed in NonOctalDecimalIntegerLiteral
• Proposal: disallow it!
• https://github.com/tc39/proposal-bigint/issues/208
• (we have tests passing on V8)

https://github.com/tc39/test262/pull/2253

Test262 Updates

@bocoup

bocoup.com

Consistency

• Numeric Separators are disallowed in LegacyOctalIntegerLiteral and NonOctalDecimalIntegerLiteral
• The change would make BigInt consistent.
• Numeric Separators would be available in any BigInt literal

Test262 Updates

@bocoup

bocoup.com

Object.keys order

• https://github.com/tc39/test262/issues/2226
• Test262 can't rely on the order from Object.keys

Test262 Updates

@bocoup

bocoup.com

Plans

• Top Level Await: https://github.com/tc39/test262/issues/2218
• Optional Chaining (still Stage 2): https://github.com/tc39/test262/pull/2212
• Everything on Stage 3!

Test262 Updates

@bocoup

bocoup.com

Engines++

• Engine262, Hermes, QuickJS, Moddable XS v9.0.0, ...
• Please allow integration with eshost and jsvu!
• https://test262.report/browse/?engines=xs (WOW at 92%!)
• Goal: add them all!

Test262 Updates

@bocoup

bocoup.com

Questions?

Test262 Updates

@bocoup

bocoup.com