This PR proposes changes to existing test262 tests to allow them to pass under Hardened JavaScript (see Secure ECMAScript proposal and Hardened JavaScript). Moddable uses Hardened JavaScript for JavaScript runtimes on resource constrained embedded devices, including those targeted by ECMA-419.
The changes fall into four groups:
1. Replace use of new Date() with new Date(1970). Scripts running inside a Compartment cannot retrieve the current time, so new Date() throws but new Date(1970) succeeds. Very few tests need the current time, but instead simply need a Date instance.
2. Use Object.defineProperty instead of setting existing built-in properties directly, such as toString and toValue. In Hardened JavaScript, prototypes of built-in objects are frozen. Consequently, setting properties of an instance that exist on the prototype throw (Hardened JavaScript is always in strict mode).
3. Eliminate use of Math.random(). Scripts running inside a Compartment cannot generate random numbers. One test identified so far uses Math.random() in a way that can easily be replaced with a counter.
4. Narrow the scope of exception tests. Consider the following
assert.throws(TypeError, () => {
var s1 = new Date();
s1.toString = Boolean.prototype.toString;
s1.toString();
});
This test passes, but only because new Date() fails by throwing a TypeError. If the invocation of the Date constructor is resolved by (1) above, then the assignment to toString fails as per (2) above. The script should be modified as below to ensure that assert.throws only tests the intended statement, s1.toString(). The modified script tests the intended functionality and passes under Hardened JavaScript
var s1 = new Date(1970);
Object.defineProperty(s1, "toString", {
value: Boolean.prototype.toString
});
assert.throws(TypeError, () => {
s1.toString();
});
This is an initial PR to begin the process of adapting test262 for use with Hardened JavaScript. Further changes are expected, with the vast majority likely to fall into the four groups described above.
Thank you to gibson042, kriskowal, and erights for their advice on this work.
toExponential had a typo, and toFixed was against an earlier version
of the specification proposal. The tests pass against a version of V8
which attempts to implement the new spec.
* Add tests for prototype realm inference
* Add tests for miscellaneous realm concerns
* Add tests for realm of spec-created Errors
In some cases, Error objects produced by the specification are
observable from ECMAScript code. Among these cases, some are further
differentiated in that they occur outside of any built-in function and
may be triggered through syntactic production directly. The current
realm record is commonly interpreted incorrectly under these
circumstances.
Add tests asserting that the expected realm record is used when
constructing such Error objects.
* Add tests for realm use in ArraySpeciesCreate
* Add tests for function realm retrieval
* Add tests for cross-realm behaviors of Symbols
* Add tests for GetValue and PutValue
* Add tests for realm of spec-created Arrays
In some cases, Arrays produced by CreateArrayFromList are observable
from ECMAScript code. Among these cases, two occur outside of any
built-in function and may be triggered through syntactic production
directly. The current realm record is commonly interpreted incorrectly
under these circumstances.
Add tests asserting that the expected realm record is used when
constructing arrays.
* Add test for spec-created object
* fixup! Add tests for realm of spec-created Errors
* fixup! Add tests for realm of spec-created Errors
* fixup! Add tests for prototype realm inference
* fixup! Add tests for miscellaneous realm concerns
The global isNaN is not precise at all, and Number.isNaN is an ES6 feature that makes it preferrable to use assert's sameValue for NaN values, as it handles it internally using the comparison.