`import defer` testing plan

[nicolo-ribaudo]

https://github.com/tc39/proposal-defer-import-eval/

Syntax

Valid cases

import defer * as ns from "mod";

import defer from "mod";

import defer * as ns from "mod";
export { ns };

Invalid cases (one per file)

import defer x from "mod";
import defer { x } from "mod";
import defer y, * as ns from "mod";
import defer as ns from "mod";
export defer * as ns from "mod";

All the existing dynamic import syntax tests should be duplicated to import.defer (both valid and invalid).

Deferred namespace object

• [x] It is an object
• [x] It is not the same object as the non-deferred one
• [ ] We should duplicate all the normal namespace object tests
• [x] Importing twice gives the same object
  • [x] static/static
  • [x] static/dynamic
  • [x] dynamic/dynamic
  • [x] static from different files
• [x] import and import defer + exec only execute the module once

Evaluation

Sync

• [x] import defer does not trigger evaluation
• [ ] import.defer does not trigger evaluation
• [x] [[Get]] triggers evaluation
  • [x] with a known export name
  • [x] with a non-exported name
  • [x] does not trigger evaluation with a symbol
• [ ] All other object operations (Reflect.*) do not trigger evaluation

Errors

• [x] Property access re-throws the evaluation error
  • [x] On first access for not evaluated modules
  • [x] On second access for not evaluated modules
  • [x] On first access for already evaluated modules
• [x] Import defer of an errored module doesn't throw
• [x] ReadyForSyncExecution
  • [x] Cannot evaluate a module in its evaluating state
  • [x] Cannot evaluate itself
  • [x] Cannot evaluate a module with a dependency in an evaluating state
  • [x] The error when evaluating a module with two dependencies, where the first one is linked and the second one is evaluating, happens before evaluating the first one
  • [x] A deferred module evaluates itself while being deferred-evaluated
  • [x] Cannot evaluate a module in its evaluating-async state
  • [x] Cannot evaluate itself after a TLA
  • [x] Cannot evaluate a module with a dependency in an evaluating-async state.
• [x] Syntax error are not deferred
• [x] Linking errors are not deferred

Async

• [x] Async modules are not deferred
• [x] Sync modules with async dep are deferred, but their async deps are not
• [x] Sync deps of async modules are not deferred
• [x] Async transitive deps are flattened and exexuted in the right order
• [ ] All these tests also for dynamic import.defer()

[ptomato]

@nicolo-ribaudo Can you suggest someone from whom it would be useful to get feedback on this testing plan?

[nicolo-ribaudo]

Maybe @takikawa who's working on an implementation, or @guybedford.