def test_context_inner_function_reassigning_deleted_value_on_deletion_of_reassignemnt_should_not_see_outer_value(
):
context_keys = set()
ctx = ContextLocal()
@ctx
def testcall():
ctx.var1 = 2
assert ctx.var1 == 2
del ctx.var1
with pytest.raises(AttributeError):
ctx.var1
ctx.var1 = 3
assert ctx.var1 == 3
del ctx.var1
# Previously deleted value should remain "deleted"
with pytest.raises(AttributeError):
ctx.var1
ctx.var1 = 1
testcall()
# Value deleted in inner context must be available here
assert ctx.var1 == 1
def test_context_isolates_async_loop():
ctx = ContextLocal()
ctx.aa = 1
results = []
@ctx
async def aiter():
ctx.aa = 3
assert ctx.aa == 3
print(ctx.aa)
assert ctx.aa == 3
ctx.aa += 1
assert ctx.aa == 4
yield 2
assert ctx.aa == 4
@ctx
async def entry():
ctx.aa = 2
counter = 0
async for i in aiter():
assert ctx.aa == 2 + counter
ctx.aa += 10
counter += 10
asyncio.run(entry())
assert ctx.aa == 1
def test_context_local_in_with_block_dont_mixup_with_other_context():
ctx1 = ContextLocal()
ctx2 = ContextLocal()
ctx1.value = 1
ctx2.value = 2
with ctx1:
ctx1.value = 3
with ctx2:
assert ctx1.value == 3
ctx2.value = 4
assert ctx1.value == 3
assert ctx2.value == 4
with ctx1:
ctx1.value = 5
assert ctx1.value == 5
assert ctx2.value == 4
assert ctx2.value == 4
assert ctx1.value == 3
assert ctx1.value == 3
assert ctx2.value == 2
assert ctx1.value == 1
assert ctx2.value == 2
def test_context_local_enter_new_context_in_with_block():
ctx = ContextLocal()
ctx.value = 1
with ctx:
ctx.value = 2
assert ctx.value == 2
assert ctx.value == 1
def test_context_local_in_with_block_can_see_outside_values():
ctx = ContextLocal()
ctx.value = 1
with ctx:
assert ctx.value == 1
ctx.value = 2
assert ctx.value == 2
assert ctx.value == 1
def test_context_run_method_isolates_context():
context_keys = set()
ctx = ContextLocal()
def testcall():
assert ctx.var1 == 1
ctx.var1 = 2
assert ctx.var1 == 2
del ctx.var1
ctx.var1 = 1
assert ctx.var1 == 1
ctx._run(testcall)
assert ctx.var1 == 1
def test_context_local_async_reflect_changes_made_downstream():
ctx = ContextLocal()
results = set()
@ctx
async def worker(value):
ctx.value = value
results.add(ctx.value)
await second_stage_worker()
assert ctx.value == value + 1
async def second_stage_worker():
await asyncio.sleep((10 - ctx.value) * 0.01)
ctx.value += 1
results.add(ctx.value)
@ctx
def manager():
ctx.value = -1
tasks = asyncio.gather(*(worker(i) for i in range(0, 10, 2)))
loop = asyncio.get_event_loop()
loop.run_until_complete(tasks)
assert all(i in results for i in range(10))
assert ctx.value == -1
manager()
def test_context_local_vars_work_for_async():
ctx = ContextLocal()
results = set()
@ctx
async def worker(value):
ctx.value = value
await asyncio.sleep((10 - value) * 0.01)
assert value == ctx.value
results.add(ctx.value)
@ctx
def manager():
ctx.value = -1
tasks = asyncio.gather(*(worker(i) for i in range(10)))
loop = asyncio.get_event_loop()
loop.run_until_complete(tasks)
assert all(i in results for i in range(10))
assert ctx.value == -1
manager()
def test_context_local_vars_work_for_threads():
ctx = ContextLocal()
results = set()
@ctx
def worker(value):
ctx.value = value
time.sleep((10 - value) * 0.01)
assert value == ctx.value
results.add(ctx.value)
@ctx
def manager():
ctx.value = -1
tasks = [
threading.Thread(target=worker, args=(i, )) for i in range(10)
]
consume(t.start() for t in tasks)
consume(t.join() for t in tasks)
assert all(i in results for i in range(10))
assert ctx.value == -1
manager()
def test_context_in_with_block_deleted_var_must_be_undeleted_outside():
ctx = ContextLocal()
ctx.value = 1
with ctx:
ctx.value = 2
assert ctx.value == 2
del ctx.value
assert ctx.value == 1
del ctx.value
with pytest.raises(AttributeError):
assert ctx.value
assert ctx.value == 1
def test_context_local_doesnt_leak_from_generator():
ctx = ContextLocal()
@ctx
def gen():
ctx.value = 2
yield
assert ctx.value == 2
ctx.value = 1
g = gen()
assert ctx.value == 1
next(g)
assert ctx.value == 1
next(g, None)
assert ctx.value == 1
def test_contexts_keep_separate_variables():
c1 = ContextLocal()
c2 = ContextLocal()
@c1
@c2
def inner():
c1.a = 1
c2.a = 2
assert c1.a == 1
assert c2.a == 2
del c2.a
with pytest.raises(AttributeError):
c2.a
assert c1.a == 1
inner()
def test_context_dir():
ctx = ContextLocal()
@ctx
def testcall():
ctx.var2 = 2
assert "var1" in dir(ctx)
assert "var2" in dir(ctx)
del ctx.var1
ctx.var1 = 1
assert "var1" in dir(ctx)
testcall()
assert "var1" in dir(ctx)
assert "var2" not in dir(ctx)
def test_context_inner_function_deleting_attribute_can_reassign_it():
context_keys = set()
ctx = ContextLocal()
@ctx
def testcall():
ctx.var1 = 2
assert ctx.var1 == 2
del ctx.var1
with pytest.raises(AttributeError):
ctx.var1
ctx.var1 = 3
assert ctx.var1 == 3
ctx.var1 = 1
testcall()
# Value deleted in inner context must be available here
assert ctx.var1 == 1
def test_context_local_vars_work_as_decorator():
ctx = ContextLocal()
@ctx
def func():
ctx.value = 1
assert ctx.value == 1
func()
with pytest.raises(AttributeError):
assert ctx.value == 1
def test_each_call_creates_unique_context_and_clean_up():
context_keys = set()
ctx = ContextLocal()
@ctx
def testcall():
context_keys.update(ctx._registry.keys())
for i in range(10):
testcall()
assert len(context_keys) == 10
assert len(list(ctx._registry.keys())) == 0
def test_context_granddaugher_works_nice_with_daughter_deleting_attribute():
context_keys = set()
ctx = ContextLocal()
@ctx
def granddaughter():
with pytest.raises(AttributeError):
ctx.var1
ctx.var1 = 2
assert ctx.var1 == 2
@ctx
def daughter():
assert ctx.var1 == 1
del ctx.var1
granddaughter()
with pytest.raises(AttributeError):
ctx.var1
ctx.var1 = 1
daughter()
assert ctx.var1 == 1
def test_unique_context_for_generators_is_cleaned_up():
context_keys = set()
ctx = ContextLocal()
@ctx
def testcall():
context_keys.update(k.value for k in ctx._registry.keys())
yield None
for i in range(100):
for _ in testcall():
pass
gc.collect()
assert len(context_keys) == 100
assert len(list(ctx._registry.keys())) == 0
def test_context_local_vars_work_for_generators():
ctx = ContextLocal()
results = []
@contextmanager
def use_mode(mode):
previous = ctx.mode
ctx.mode = mode
try:
yield
finally:
ctx.mode = previous
@ctx
def first():
ctx.mode = 0
results.append(("starting", ctx.mode))
with use_mode(1):
results.append(("entered first", ctx.mode))
it = second()
next(it)
results.append(("back in first", ctx.mode))
next(it, None)
results.append(("ended second", ctx.mode))
results.append(("exited first context manager", ctx.mode))
@ctx
def second():
with use_mode(2):
results.append(("entered second", ctx.mode))
yield
results.append(("back in second", ctx.mode))
results.append(("exited second context manager", ctx.mode))
first()
assert results == [('starting', 0), ('entered first', 1),
('entered second', 2), ('back in first', 1),
('back in second', 2),
('exited second context manager', 1),
('ended second', 1),
('exited first context manager', 0)]
def test_context_local_enter_new_context_in_nested_with_blocks():
ctx = ContextLocal()
ctx.value = 1
with ctx:
ctx.value = 2
with ctx:
ctx.value = 3
with ctx:
ctx.value = 4
assert ctx.value == 4
assert ctx.value == 3
assert ctx.value == 2
assert ctx.value == 1
https://stackoverflow.com/questions/53611690/how-do-i-write-consistent-stateful-context-managers/57448146
"""
# Code demonstrating how generators
# entered in different calls can each
# have a separate context
from contextlib import contextmanager
#from contextvars import ContextVar, Context, copy_context
from extracontext import ContextLocal
ctx = ContextLocal()
@contextmanager
def use_mode(mode):
ctx.MODE = mode
print("entering use_mode")
print_mode()
try:
yield
finally:
pass
def print_mode():