test_event_loop.py

import pytest
import pythonmonkey as pm
import asyncio


def test_setTimeout_unref():
  async def async_fn():
    obj = {'val': 0}
    pm.eval("""(obj) => {
            setTimeout(()=>{ obj.val = 2 }, 1000).ref().ref().unref().ref().unref().unref();
                // chaining, no use on the first two ref calls since it's already refed initially
            setTimeout(()=>{ obj.val = 1 }, 100);
        }""")(obj)
    await pm.wait()  # we shouldn't wait until the first timer is fired since it's currently unrefed
    assert obj['val'] == 1

    # making sure the async_fn is run
    return True
  assert asyncio.run(async_fn())


def test_setInterval_unref():
  async def async_fn():
    obj = {'val': 0}
    pm.eval("""(obj) => {
            setInterval(()=>{ obj.val++ }, 200).unref()
            setTimeout(()=>{ }, 500)
        }""")(obj)
    await pm.wait()  # It should stop after the setTimeout timer's 500ms.
    assert obj['val'] == 2  # The setInterval timer should only run twice (500 // 200 == 2)
    return True
  assert asyncio.run(async_fn())


def test_clearInterval():
  async def async_fn():
    obj = {'val': 0}
    pm.eval("""(obj) => {
            const interval = setInterval(()=>{ obj.val++ }, 200)
            setTimeout(()=>{ clearInterval(interval) }, 500)
        }""")(obj)
    await pm.wait()  # It should stop after 500ms on the clearInterval
    assert obj['val'] == 2  # The setInterval timer should only run twice (500 // 200 == 2)
    return True
  assert asyncio.run(async_fn())


def test_finished_timer_ref():
  async def async_fn():
    # Making sure the event-loop won't be activated again when a finished timer gets re-refed.
    pm.eval("""
            const timer = setTimeout(()=>{}, 100);
            setTimeout(()=>{ timer.ref() }, 200);
        """)
    await pm.wait()
    return True
  assert asyncio.run(async_fn())


def test_set_clear_timeout():
  # throw RuntimeError outside a coroutine
  with pytest.raises(RuntimeError,
                     match="PythonMonkey cannot find a running Python event-loop to make asynchronous calls."):
    pm.eval("setTimeout")(print)

  async def async_fn():
    # standalone `setTimeout`
    loop = asyncio.get_running_loop()
    f0 = loop.create_future()

    def add(a, b, c):
      f0.set_result(a + b + c)
    pm.eval("setTimeout")(add, 0, 1, 2, 3)
    assert 6.0 == await f0

    # test `clearTimeout`
    f1 = loop.create_future()

    def to_raise(msg):
      f1.set_exception(TypeError(msg))
    timeout_id0 = pm.eval("setTimeout")(to_raise, 100, "going to be there")
    # `setTimeout` should return a `Timeout` instance wrapping a positive integer value
    assert pm.eval("(t) => t instanceof setTimeout.Timeout")(timeout_id0)
    assert pm.eval("(t) => Number(t) > 0")(timeout_id0)
    assert pm.eval("(t) => Number.isInteger(Number(t))")(timeout_id0)
    with pytest.raises(TypeError, match="going to be there"):
      await f1                                # `clearTimeout` not called
    f1 = loop.create_future()
    timeout_id1 = pm.eval("setTimeout")(to_raise, 100, "shouldn't be here")
    pm.eval("clearTimeout")(timeout_id1)
    with pytest.raises(asyncio.exceptions.TimeoutError):
      await asyncio.wait_for(f1, timeout=0.5)  # `clearTimeout` is called

    # `this` value in `setTimeout` callback should be the global object, as spec-ed
    assert await pm.eval("new Promise(function (resolve) { setTimeout(function(){ resolve(this == globalThis) }) })")
    # `setTimeout` should allow passing additional arguments to the callback, as spec-ed
    assert 3.0 == await pm.eval("""
                    new Promise((resolve) => setTimeout(function(){
                      resolve(arguments.length);
                    },
                    100, 90, 91, 92))
                  """)
    assert 92.0 == await pm.eval("""
                      new Promise((resolve) => setTimeout((...args) => {
                        resolve(args[2]);
                      },
                      100, 90, 91, 92))
                    """)
    # test `setTimeout` setting delay to 0 if < 0
    await asyncio.wait_for(pm.eval("new Promise((resolve) => setTimeout(resolve, 0))"), timeout=0.05)
    # won't be precisely 0s
    await asyncio.wait_for(pm.eval("new Promise((resolve) => setTimeout(resolve, -10000))"), timeout=0.05)
    # test `setTimeout` accepting string as the delay, coercing to a number.
    # Number('100') -> 100, pass if the actual delay is > 90ms and < 150ms
    # won't be precisely 100ms
    await asyncio.wait_for(pm.eval("new Promise((resolve) => setTimeout(resolve, '100'))"), timeout=0.15)
    with pytest.raises(asyncio.exceptions.TimeoutError):
      await asyncio.wait_for(pm.eval("new Promise((resolve) => setTimeout(resolve, '100'))"), timeout=0.09)
    # Number("1 second") -> NaN -> delay turns to be 0s
    # won't be precisely 0s
    await asyncio.wait_for(pm.eval("new Promise((resolve) => setTimeout(resolve, '1 second'))"), timeout=0.5)

    # passing an invalid ID to `clearTimeout` should silently do nothing; no exception is thrown.
    pm.eval("clearTimeout(NaN)")
    pm.eval("clearTimeout(999)")
    pm.eval("clearTimeout(-1)")
    pm.eval("clearTimeout('a')")
    pm.eval("clearTimeout(undefined)")
    pm.eval("clearTimeout()")

    # passing a `code` string to `setTimeout` as the callback function
    assert "code string" == await pm.eval("""
        new Promise((resolve) => {
            globalThis._resolve = resolve
            setTimeout("globalThis._resolve('code string'); delete globalThis._resolve", 100)
        })
        """)

    # making sure the async_fn is run
    return True
  assert asyncio.run(async_fn())

  # throw RuntimeError outside a coroutine (the event-loop has ended)
  with pytest.raises(RuntimeError,
                     match="PythonMonkey cannot find a running Python event-loop to make asynchronous calls."):
    pm.eval("setTimeout")(print)


def test_promises():
  # should throw RuntimeError if Promises are created outside a coroutine
  create_promise = pm.eval("() => Promise.resolve(1)")
  with pytest.raises(RuntimeError,
                     match="PythonMonkey cannot find a running Python event-loop to make asynchronous calls."):
    create_promise()

  async def async_fn():
    create_promise()  # inside a coroutine, no error

    # Python awaitables to JS Promise coercion
    # 1. Python asyncio.Future to JS promise
    loop = asyncio.get_running_loop()
    f0 = loop.create_future()
    f0.set_result(2561)

    assert type(f0) is asyncio.Future
    assert 2561 == await f0
    assert pm.eval("(p) => p instanceof Promise")(f0) is True
    assert 2561 == await pm.eval("(p) => p")(f0)
    del f0

    # 2. Python asyncio.Task to JS promise
    async def coro_fn(x):
      await asyncio.sleep(0.01)
      return x
    task = loop.create_task(coro_fn("from a Task"))
    assert type(task) is asyncio.Task
    assert type(task) is not asyncio.Future
    assert isinstance(task, asyncio.Future)
    assert "from a Task" == await task
    assert pm.eval("(p) => p instanceof Promise")(task) is True
    assert "from a Task" == await pm.eval("(p) => p")(task)
    del task

    # 3. Python coroutine to JS promise
    coro = coro_fn("from a Coroutine")
    assert asyncio.iscoroutine(coro)
    # assert "a Coroutine" == await coro                   # coroutines cannot be awaited more than once
    # assert pm.eval("(p) => p instanceof Promise")(coro)  # RuntimeError: cannot reuse already awaited coroutine
    assert "from a Coroutine" == await pm.eval("(p) => (p instanceof Promise) && p")(coro)
    del coro

    # JS Promise to Python awaitable coercion
    assert 100 == await pm.eval("new Promise((r)=>{ r(100) })")
    assert 10010 == await pm.eval("Promise.resolve(10010)")
    with pytest.raises(pm.SpiderMonkeyError, match="^TypeError: (.|\\n)+ is not a constructor$"):
      await pm.eval("Promise.resolve")(10086)
    assert 10086 == await pm.eval("Promise.resolve.bind(Promise)")(10086)

    assert "promise returning a function" == (await pm.eval("""
                                                              Promise.resolve(() => {
                                                                return 'promise returning a function';
                                                              });
                                                            """))()
    assert "function 2" == (await pm.eval("Promise.resolve(x=>x)"))("function 2")

    def aaa(n):
      return n
    ident0 = await (pm.eval("Promise.resolve.bind(Promise)")(aaa))
    assert "from aaa" == ident0("from aaa")
    ident1 = await pm.eval("async (aaa) => x=>aaa(x)")(aaa)
    assert "from ident1" == ident1("from ident1")
    ident2 = await pm.eval("() => Promise.resolve(x=>x)")()
    assert "from ident2" == ident2("from ident2")
    ident3 = await pm.eval("(aaa) => Promise.resolve(x=>aaa(x))")(aaa)
    assert "from ident3" == ident3("from ident3")
    del aaa

    # promise returning a JS Promise<Function> that calls a Python function inside
    def fn0(n):
      return n + 100

    def fn1():
      return pm.eval("async x=>x")(fn0)
    fn2 = await pm.eval("async (fn1) => { const fn0 = await fn1(); return Promise.resolve(x=>fn0(x)) }")(fn1)
    assert 101.2 == fn2(1.2)
    fn3 = await pm.eval("""
      async (fn1) => {
        const fn0 = await fn1();
        return Promise.resolve(async x => { return fn0(x); });
      }
    """)(fn1)
    assert 101.3 == await fn3(1.3)
    fn4 = await pm.eval("""
      async (fn1) => {
        return Promise.resolve(async x => {
          const fn0 = await fn1();
          return fn0(x);
        });
      }
    """)(fn1)
    assert 101.4 == await fn4(1.4)

    # chained JS promises
    assert "chained" == await pm.eval("""
                          async () => new Promise((resolve) => resolve( Promise.resolve().then(()=>'chained') ))
                        """)()

    # chained Python awaitables
    async def a():
      await asyncio.sleep(0.01)
      return "nested"

    async def b():
      await asyncio.sleep(0.01)
      return a()

    async def c():
      await asyncio.sleep(0.01)
      return b()
    # JS `await` supports chaining. However, on Python-land, it actually requires `await (await (await c()))`
    assert "nested" == await pm.eval("async (promise) => await promise")(c())
    assert "nested" == await pm.eval("async (promise) => await promise")(await c())
    assert "nested" == await pm.eval("async (promise) => await promise")(await (await c()))
    assert "nested" == await pm.eval("async (promise) => await promise")(await (await (await c())))
    assert "nested" == await pm.eval("async (promise) => promise")(c())
    assert "nested" == await pm.eval("async (promise) => promise")(await c())
    assert "nested" == await pm.eval("async (promise) => promise")(await (await c()))
    assert "nested" == await pm.eval("async (promise) => promise")(await (await (await c())))
    assert "nested" == await pm.eval("(promise) => Promise.resolve(promise)")(c())
    assert "nested" == await pm.eval("(promise) => Promise.resolve(promise)")(await c())
    assert "nested" == await pm.eval("(promise) => Promise.resolve(promise)")(await (await c()))
    assert "nested" == await pm.eval("(promise) => Promise.resolve(promise)")(await (await (await c())))
    assert "nested" == await pm.eval("(promise) => promise")(c())
    assert "nested" == await pm.eval("(promise) => promise")(await c())
    assert "nested" == await pm.eval("(promise) => promise")(await (await c()))
    with pytest.raises(TypeError, match="object str can't be used in 'await' expression"):
      await pm.eval("(promise) => promise")(await (await (await c())))

    # Python awaitable throwing exceptions
    async def coro_to_throw0():
      await asyncio.sleep(0.01)
      print([].non_exist)  # type: ignore
    with pytest.raises(pm.SpiderMonkeyError, match="Python AttributeError: 'list' object has no attribute 'non_exist'"):
      await (pm.eval("(promise) => promise")(coro_to_throw0()))
    with pytest.raises(pm.SpiderMonkeyError, match="Python AttributeError: 'list' object has no attribute 'non_exist'"):
      await (pm.eval("async (promise) => promise")(coro_to_throw0()))
    with pytest.raises(pm.SpiderMonkeyError, match="Python AttributeError: 'list' object has no attribute 'non_exist'"):
      await (pm.eval("(promise) => Promise.resolve().then(async () => await promise)")(coro_to_throw0()))

    async def coro_to_throw1():
      await asyncio.sleep(0.01)
      raise TypeError("reason")
    with pytest.raises(pm.SpiderMonkeyError, match="Python TypeError: reason"):
      await (pm.eval("(promise) => promise")(coro_to_throw1()))
    assert 'rejected <Python TypeError: reason>' == await pm.eval("""
                                                                  (promise) => promise.then(
                                                                    ()=>{},
                                                                    (err)=>`rejected <${err.message}>`
                                                                  )
                                                                  """)(coro_to_throw1())

    # JS Promise throwing exceptions
    with pytest.raises(pm.SpiderMonkeyError, match="nan"):
      await pm.eval("Promise.reject(NaN)")  # JS can throw anything
    with pytest.raises(pm.SpiderMonkeyError, match="123.0"):
      await (pm.eval("async () => { throw 123 }")())
      # await (pm.eval("async () => { throw {} }")())
    with pytest.raises(pm.SpiderMonkeyError, match="anything"):
      await pm.eval("Promise.resolve().then(()=>{ throw 'anything' })")
      # FIXME (Tom Tang): We currently handle Promise exceptions by converting the object thrown to a Python Exception
      # object through `pyTypeFactory
      #               <objects of this type are not handled by PythonMonkey yet>
      # await pm.eval("Promise.resolve().then(()=>{ throw {a:1,toString(){return'anything'}} })")
    # not going through the conversion
    with pytest.raises(pm.SpiderMonkeyError, match="on line 1, column 31:\nTypeError: undefined has no properties"):
      await pm.eval("Promise.resolve().then(()=>{ (undefined).prop })")

    # TODO (Tom Tang): Modify this testcase once we support ES2020-style dynamic import
    # pm.eval("import('some_module')") # dynamic import returns a Promise, see
    # https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/import
    with pytest.raises(pm.SpiderMonkeyError,
                       match="\nError: Dynamic module import is disabled or not supported in this context"):
      await pm.eval("import('some_module')")
    # TODO (Tom Tang): properly test unhandled rejection

    # await scheduled jobs on the Python event-loop
    js_sleep = pm.eval("(seconds) => new Promise((resolve) => setTimeout(resolve, seconds*1000))")

    def py_sleep(seconds):  # asyncio.sleep has issues on Python 3.8
      loop = asyncio.get_running_loop()
      future = loop.create_future()
      loop.call_later(seconds, lambda: future.set_result(None))
      return future
    both_sleep = pm.eval("""
      (js_sleep, py_sleep) => async (seconds) => {
        await js_sleep(seconds);
        await py_sleep(seconds);
      }
    """)(js_sleep, py_sleep)
    await asyncio.wait_for(both_sleep(0.1), timeout=0.3)  # won't be precisely 0.2s
    with pytest.raises(asyncio.exceptions.TimeoutError):
      await asyncio.wait_for(both_sleep(0.1), timeout=0.19)

    # making sure the async_fn is run
    return True
  assert asyncio.run(async_fn())

  # should throw a RuntimeError if created outside a coroutine (the event-loop has ended)
  with pytest.raises(RuntimeError,
                     match="PythonMonkey cannot find a running Python event-loop to make asynchronous calls."):
    pm.eval("new Promise(() => { })")


def test_errors_thrown_in_promise():
  async def async_fn():
    loop = asyncio.get_running_loop()
    future = loop.create_future()

    def exceptionHandler(loop, context):
      future.set_exception(context["exception"])
    loop.set_exception_handler(exceptionHandler)

    pm.eval("""
    new Promise(function (resolve, reject)
    {
      reject(new Error('in Promise'));
    });

    new Promise(function (resolve, reject)
    {
      console.log('ok');
    });
    """)
    with pytest.raises(pm.SpiderMonkeyError, match="Error: in Promise"):
      await asyncio.wait_for(future, timeout=0.1)

    loop.set_exception_handler(None)
    return True
  assert asyncio.run(async_fn())


def test_errors_thrown_in_async_function():
  async def async_fn():
    loop = asyncio.get_running_loop()
    future = loop.create_future()

    def exceptionHandler(loop, context):
      future.set_exception(context["exception"])
    loop.set_exception_handler(exceptionHandler)

    pm.eval("""
    async function aba() {
      throw new Error('in async function');
    }

    async function abb() {
      console.log('ok');
    }

    aba();
    abb();
    """)
    with pytest.raises(pm.SpiderMonkeyError, match="Error: in async function"):
      await asyncio.wait_for(future, timeout=0.1)

    loop.set_exception_handler(None)
    return True
  assert asyncio.run(async_fn())


def test_webassembly():
  """
  Tests for off-thread promises
  """
  async def async_fn():
    # off-thread promises can run
    assert 'instantiated' == await pm.eval("""
        // https://github.com/mdn/webassembly-examples/blob/main/js-api-examples/simple.wasm
        var code = new Uint8Array([
            0,  97, 115, 109,   1,   0,   0,   0,   1,   8,   2,  96,
            1, 127,   0,  96,   0,   0,   2,  25,   1,   7, 105, 109,
        112, 111, 114, 116, 115,  13, 105, 109, 112, 111, 114, 116,
        101, 100,  95, 102, 117, 110,  99,   0,   0,   3,   2,   1,
            1,   7,  17,   1,  13, 101, 120, 112, 111, 114, 116, 101,
        100,  95, 102, 117, 110,  99,   0,   1,  10,   8,   1,   6,
            0,  65,  42,  16,   0,  11
        ]);

        WebAssembly.instantiate(code, { imports: { imported_func() {} } }).then(() => 'instantiated')
        """)

    # making sure the async_fn is run
    return True
  assert asyncio.run(async_fn())