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.
Prior to this commit, the descriptors of the constructor properties of
the global object were verified inconsistently, many independent
assertions occured in the same file, and that file test was poorly
located.
Restructure the relevant tests to improve coverage, follow convention,
and promote discoverability.
* 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
This function is equivalent to `$ERROR` (which is automatically included
in test environments). Remove the harness file that defines the
function, remove references to the file from test `includes` lists, and
update scripts to instead invoke the `$ERROR` function.
- Remove no longer needed noStrict flags.
- Change tests to use propertyHelper.js for strict mode compatibility.
- Add tests for return value of `delete` operator, e.g. `delete Array.prototype === false`.
- Add non-writable tests for global NaN property.
- Split some tests to run in strict mode.
- Change tests with global `var length` declaration to use a different variable name for browser environments.
- Merge duplicated tests symbol-data-property-configurable-non-strict and symbol-data-property-configurable-strict.
- Merge duplicated tests symbol-data-property-writable-non-strict and symbol-data-property-writable-strict.
- (And a small change in propertyHelper to reduce code duplication in function call.)