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.
For the statement level test, the inner class name is not initialized
at the time the decorators evaluate, resulting in a ReferenceError
that the declaration can not be accessed prior to initialization.
Similar, non-decorator code, like:
class C {
static dec() {}
static {
this.x = C.dec();
class C {}
}
}
also results in a ReferenceError.
For the expression level test, the var C is undefined at the time the
decorators are evaluated, resulting in TypeError while trying to access
a member of undefined.
Similar, non-decorator code, like:
var C = class {
static f() {};
static {
this.x = C.f();
}
}
also results in a TypeError.
While we're at it, use assert() instead of assert.sameValue() for brevity,
if we are not specifically testing that the return value of hasOwnProperty
is the value true or false; and add more informative assertion messages to
help with debugging.
In some cases, the Object.hasOwnProperty.call could be replaced with
verifyProperty(), if the property descriptor was also being verified at
the same time.
This fixes some tests that were faulty to begin with: a common mistake was
Object.hasOwnProperty(obj, prop) which is probably going to return false
when that's not what you want.
The only instances left of `Object.hasOwnProperty` are one regression test
in implementation-contributed which I can't tell if it was intentionally
needed to trigger the regression, and a few instances of
`Object.hasOwnProperty('prototype')` which would defeat the purpose to
convert into `Object.prototype.hasOwnProperty.call(Object, 'prototype')`
form.
Closes: #3524
Prior to this commit, two tests for specific early errors also included
syntactically invalid `const` declarations. Implementations which
produced the expected syntax error due to these invalid declarations
would pass the tests regardless of whether they produced the early
errors that the tests were written to verify.
Correct the `const` declarations so that the tests verify the parsing
rule that they were designed to verify.
The test as originally specified fails in all compatible parsers, but for the wrong reason. Below is an excerpt from V8, but all parser I tested behave the same:
```js
for (const x; false; ) {
^
SyntaxError: Missing initializer in const declaration
```
After the change the error is the assumed:
```js
var x;
^
SyntaxError: Identifier 'x' has already been declared
```
As originally written, this test would spuriously pass when the deleted
property was incorrectly visited by enumation but correctly removed from
the object. In such cases, the accumulator string would take the form
"aa1baundefinedca3"
And satisfy all conditions intended to highlight implementation errors.
Refactor the test to avoid false negative by using an object with a null
prototype and verifying the exact contents of the accumulator string.
As originally written, this test would spuriously pass when the deleted
property was incorrectly visited by enumation but correctly removed from
the object. In such cases, the accumulator string would take the form
"aa1baundefinedca3"
And satisfy all conditions intended to highlight implementation errors.
Refactor the test to avoid false negative by using an object with a null
prototype and verifying the exact contents of the accumulator string.
Some tests which include function declarations designed to verify
behavior do not reference those functions. Insert the references
necessary for those functions to serve their intended purpose.
This reverts commit b690cb67be, reversing
changes made to 50dd431dff. This is
necessary because the reverted changeset reduced coverage by an unknown
extent.
Prior to this commit, the modified tests used the strict equality
operator to compare computed values with negative zero. Due to the
semantics of that operator, these tests would spuriously pass if the
value under test was in fact positive zero.
Update the tests to be more precise by instead asserting equality with
the `assert.sameValue` utility method (since that method correctly
distinguishes between negative zero and positive zero).
André Bargull
Ron Buckton
Ioanna M Dimitriou H
Nicolò Ribaudo
Ioanna M Dimitriou H
Peter Hoddie
Linus Groh
Kevin Gibbons
Daniel Minor
Huáng Jùnliàng
José Julián Espina
Cam Tenny
Philip Chimento
legendecas
Youssef Soliman
Mike Pennisi
Dmitriy Kubyshkin
Keith Miller
rwaldron
Rick Waldron