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import pytest
from .. import aclosing, async_generator, yield_, asynccontextmanager
@async_generator
async def async_range(count, closed_slot):
try:
for i in range(count): # pragma: no branch
await yield_(i)
except GeneratorExit:
closed_slot[0] = True
async def test_aclosing():
closed_slot = [False]
async with aclosing(async_range(10, closed_slot)) as gen:
it = iter(range(10))
async for item in gen: # pragma: no branch
assert item == next(it)
if item == 4:
break
assert closed_slot[0]
closed_slot = [False]
try:
async with aclosing(async_range(10, closed_slot)) as gen:
it = iter(range(10))
async for item in gen: # pragma: no branch
assert item == next(it)
if item == 4:
raise ValueError()
except ValueError:
pass
assert closed_slot[0]
async def test_contextmanager_do_not_unchain_non_stopiteration_exceptions():
@asynccontextmanager
@async_generator
async def manager_issue29692():
try:
await yield_()
except Exception as exc:
raise RuntimeError('issue29692:Chained') from exc
with pytest.raises(RuntimeError) as excinfo:
async with manager_issue29692():
raise ZeroDivisionError
assert excinfo.value.args[0] == 'issue29692:Chained'
assert isinstance(excinfo.value.__cause__, ZeroDivisionError)
# This is a little funky because of implementation details in
# async_generator It can all go away once we stop supporting Python3.5
with pytest.raises(RuntimeError) as excinfo:
async with manager_issue29692():
exc = StopIteration('issue29692:Unchained')
raise exc
assert excinfo.value.args[0] == 'issue29692:Chained'
cause = excinfo.value.__cause__
assert cause.args[0] == 'generator raised StopIteration'
assert cause.__cause__ is exc
with pytest.raises(StopAsyncIteration) as excinfo:
async with manager_issue29692():
raise StopAsyncIteration('issue29692:Unchained')
assert excinfo.value.args[0] == 'issue29692:Unchained'
assert excinfo.value.__cause__ is None
@asynccontextmanager
@async_generator
async def noop_async_context_manager():
await yield_()
with pytest.raises(StopIteration):
async with noop_async_context_manager():
raise StopIteration
# Native async generators are only available from Python 3.6 and onwards
nativeasyncgenerators = True
try:
exec(
"""
@asynccontextmanager
async def manager_issue29692_2():
try:
yield
except Exception as exc:
raise RuntimeError('issue29692:Chained') from exc
"""
)
except SyntaxError:
nativeasyncgenerators = False
@pytest.mark.skipif(
not nativeasyncgenerators,
reason="Python < 3.6 doesn't have native async generators"
)
async def test_native_contextmanager_do_not_unchain_non_stopiteration_exceptions(
):
with pytest.raises(RuntimeError) as excinfo:
async with manager_issue29692_2():
raise ZeroDivisionError
assert excinfo.value.args[0] == 'issue29692:Chained'
assert isinstance(excinfo.value.__cause__, ZeroDivisionError)
for cls in [StopIteration, StopAsyncIteration]:
with pytest.raises(cls) as excinfo:
async with manager_issue29692_2():
raise cls('issue29692:Unchained')
assert excinfo.value.args[0] == 'issue29692:Unchained'
assert excinfo.value.__cause__ is None
async def test_asynccontextmanager_exception_passthrough():
# This was the cause of annoying coverage flapping, see gh-140
@asynccontextmanager
@async_generator
async def noop_async_context_manager():
await yield_()
for exc_type in [StopAsyncIteration, RuntimeError, ValueError]:
with pytest.raises(exc_type):
async with noop_async_context_manager():
raise exc_type
# And let's also check a boring nothing pass-through while we're at it
async with noop_async_context_manager():
pass
async def test_asynccontextmanager_catches_exception():
@asynccontextmanager
@async_generator
async def catch_it():
with pytest.raises(ValueError):
await yield_()
async with catch_it():
raise ValueError
async def test_asynccontextmanager_different_exception():
@asynccontextmanager
@async_generator
async def switch_it():
try:
await yield_()
except KeyError:
raise ValueError
with pytest.raises(ValueError):
async with switch_it():
raise KeyError
async def test_asynccontextmanager_nice_message_on_sync_enter():
@asynccontextmanager
@async_generator
async def xxx(): # pragma: no cover
await yield_()
cm = xxx()
with pytest.raises(RuntimeError) as excinfo:
with cm:
pass # pragma: no cover
assert "async with" in str(excinfo.value)
async with cm:
pass
async def test_asynccontextmanager_no_yield():
@asynccontextmanager
@async_generator
async def yeehaw():
pass
with pytest.raises(RuntimeError) as excinfo:
async with yeehaw():
assert False # pragma: no cover
assert "didn't yield" in str(excinfo.value)
async def test_asynccontextmanager_too_many_yields():
closed_count = 0
@asynccontextmanager
@async_generator
async def doubleyield():
try:
await yield_()
except Exception:
pass
try:
await yield_()
finally:
nonlocal closed_count
closed_count += 1
with pytest.raises(RuntimeError) as excinfo:
async with doubleyield():
pass
assert "didn't stop" in str(excinfo.value)
assert closed_count == 1
with pytest.raises(RuntimeError) as excinfo:
async with doubleyield():
raise ValueError
assert "didn't stop after athrow" in str(excinfo.value)
assert closed_count == 2
async def test_asynccontextmanager_requires_asyncgenfunction():
with pytest.raises(TypeError):
@asynccontextmanager
def syncgen(): # pragma: no cover
yield
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