Tests for the stage 3 proposal at
https://tc39.github.io/proposal-regexp-lookbehind/

Tests ported from V8, written by @hashseed

Proposal from @mathiasbynens at https://github.com/tc39/proposal-regexp-dotall-flag and https://tc39.github.io/proposal-regexp-dotall-flag/

Tests against the Stage 3 named capture groups proposal
https://tc39.github.io/proposal-regexp-named-groups

Signed-off-by: Rick Waldron <waldron.rick@gmail.com>

* Move decimalToHexString into harness instead of duplicating it in multiple files

* Optimize decimalToHexString and support numbers greater than 65535

* Replace alternative decimalToHexString function with include for decimalToHexString.js

* Add decimalToHex2String to return the string representation of a two-digit hex-number

* Replace decimalToHex2String with decimalToPercentHexString to return the percent hex-encoded string of a two-digit hex-number

* Replace two String.fromCharCode calls with a single call

* Further reduce string concatentations in decodeURI[Component] tests

* Remove unnecessary Test262Error error handling in catch-clauses

* Remove try/catch wrappings in decodeURI/encodeURI tests

As the author of these files, I can verify that they were contributed in
2015 on behalf of the V8 project.

Ref. https://github.com/tc39/proposal-regexp-unicode-property-escapes/issues/27.

Ref. https://github.com/mathiasbynens/node-unicode-data/issues/45.
Ref. https://github.com/mathiasbynens/regenerate-unicode-properties/commit/da8ae69b9b8a11be16394d7fa183ccc9d68337db.
Ref. https://github.com/mathiasbynens/unicode-property-escapes-tests/issues/7.

https://github.com/mathiasbynens/unicode-property-escapes-tests/commit/c62ed61cfc7c3c7d596f922facee2c0152555d8f

Proposal: https://github.com/tc39/proposal-regexp-unicode-property-escapes

These tests have been generated by the script at https://github.com/mathiasbynens/unicode-property-escapes-tests. They check all the properties and values that should be supported by implementations against the symbols they’re supposed to match. False positives are detected as well.

Ref. #950.
Ref. https://github.com/tc39/proposal-regexp-unicode-property-escapes/issues/4.

The `length` property should be [[Configurable]]
https://tc39.github.io/ecma262/#sec-function.prototype.bind

Also the test was testing deleting the wrong property.

Fixes #957.

* Add Function.prototype.toString tests for many function forms
* Add non-const computed property name to Function.prototype.toString tests
* Split class method tests into class-expression and class-statement tests
* Add tests for unnamed function expression forms
* Add tests for async (generator) methods in class contexts
* Add test case for Function.prototype.toString on async arrow function

Signed-off-by: Rick Waldron <waldron.rick@gmail.com>

Bug was reported by @anba at
https://github.com/tc39/ecma262/pull/852#issuecomment-291781031

Without this change, you'd expect a RangeError rather than a TypeError.

In https://github.com/tc39/ecma262/pull/853 , standard semantics
for this case are proposed. This patch tests the case.

The change is proposed in https://github.com/tc39/ecma262/pull/856
as a fix to https://github.com/tc39/ecma262/issues/855

Here, the ToNumber coercion is done only once, rather than on each
iteration. It does not appear that there were previously any
tests against repeated coercion for this parameter previously.

Tested this test against V8, which failed, as V8 implements the
current spec rather than the proposed one.

This test comes from a note in the specification under toFixed.
It fails in ChakraCore and passes in other engines that I tested.

This test is only valid with the PR in https://github.com/tc39/ecma262/pull/852

Detached buffer causes an exception
- If it's already detached going into the constructor
- If the byteOffset coercion causes it to be detached

Tests are valid in ES2017

Fixes #767

Fixes #779

Fix 850

Fixes #793

As described by @ediosyncratic:

Date(0) flows through the given algorithm to ToDateString, which should:

> Return an implementation-dependent String value that represents tv as
> a date and time in the current time zone using a convenient, human-readable form.

The string is implementation-dependent and there is nothing constraining it to use
a two-digit day-of-month (so "Thu Jan 1, 1970, 0:0:0" would be valid), much less to
position it at index 8.

Fixes #861
Ref #849

Based on the cases from TypedArray.prototype.copyWithin

Fixes #875

Signed-off-by: Rick Waldron <waldron.rick@gmail.com>

Some popular JavaScript engines display violation of invariants about
property attributes for some non-standard but “web-reality” object
properties. Add tests against such violations

Closes #653
Fixes #649