Tests

[domenic]

Must be in test262 format. Ideally use the Node test262 runner @bterlson is developing (which I will probably submit patches to in the process).

• Smoke tests
• Array-like
• Holes
• ToObject
• zero length (array and array-like)
• negative length
• throwing getters should cause error to be rethrown at the right algorithm step
• ToLength works: missing .length property; negative; above max-length; Infinities; NaN; valueOf
• fromIndex: above .length
• fromIndex: between -.length and 0
• fromIndex: -.length
• fromIndex: below -.length
• fromIndex: rounding behavior
• fromIndex: infinities; NaN; valueOf
• SameValueZero (kind of duplicated by smoke tests)
• non-primitives get found correctly
• Mutate global objects (e.g. global.Object) to ensure they are not called. Will probably require fixing especially to make the reference implementation pass.
• Check the .length property
• Check the property descriptor (non-enumerable, configurable, writable; test both the propdesc directly and the behaviors. test262 has helpers for this already).
• Check the name

[domenic]

After some stabs at this, my discoveries:

• TDDing from scratch is hard. I may instead just implement a polyfill and then do massive test coverage.
• Don't forget to write tests that mutate global state. E.g. by modifying global.Object we can ensure that the ToObject call is not implemented in terms of global.Object.

[domenic]

Test coverage finished, as far as I can see!