async def test_pipe_complex_pipe():
xs = rx.from_iterable([1, 2, 3])
result = []
def mapper(value: int) -> int:
return value * 10
async def predicate(value: int) -> bool:
await asyncio.sleep(0.1)
return value > 1
def long_running(value: int) -> AsyncObservable[int]:
return rx.from_iterable([value])
ys = pipe(
xs,
rx.filter_async(predicate),
rx.map(mapper),
rx.flat_map(long_running),
rx.to_async_iterable,
)
async for value in ys:
result.append(value)
assert result == [20, 30]
async def test_flat_map_monad():
m = rx.single(42)
def mapper(x: int) -> AsyncObservable[int]:
return rx.single(x * 10)
a = await rx.run(pipe(m, rx.flat_map(mapper)))
b = await rx.run(rx.single(420))
assert a == b
async def test_flat_map_monad_law_associativity():
# (m >>= f) >>= g is just like doing m >>= (\x -> f x >>= g)
m = rx.single(42)
def f(x: int) -> AsyncObservable[int]:
return rx.single(x + 1000)
def g(y: int) -> AsyncObservable[int]:
return rx.single(y * 333)
def h(x: int) -> AsyncObservable[int]:
return pipe(f(x), rx.flat_map(g))
zs = pipe(m, rx.flat_map(f))
a = await rx.run(pipe(zs, rx.flat_map(g)))
b = await rx.run(pipe(m, rx.flat_map(h)))
assert a == b
async def test_flat_map_monad_law_right_identity():
# m >>= return is no different than just m.
m = rx.single("move on up")
def mapper(x: str) -> AsyncObservable[str]:
return rx.single(x)
a = await rx.run(pipe(m, rx.flat_map(mapper)))
b = await rx.run(m)
assert a == b
async def test_flat_map_monad_law_left_identity():
# return x >>= f is the same thing as f x
x = 3
def f(x: int) -> AsyncObservable[int]:
return rx.single(x + 100000)
a = await rx.run(pipe(rx.single(x), rx.flat_map(f)))
b = await rx.run(f(x))
assert a == b
async def test_flap_map_done():
xs: rx.AsyncSubject[int] = rx.AsyncSubject()
def mapper(value: int) -> rx.AsyncObservable[int]:
return rx.from_iterable([value])
ys = pipe(xs, rx.flat_map(mapper))
obv = AsyncTestObserver()
await ys.subscribe_async(obv)
await xs.asend(10)
await xs.asend(20)
await xs.aclose()
await obv
assert obv.values == [(0, OnNext(10)), (0, OnNext(20)), (0, OnCompleted)]
def h(x: int) -> AsyncObservable[int]:
return pipe(f(x), rx.flat_map(g))