Rewritting Bags from scratch using a namedtuple approach, along with other (less major) updates.

New bag implementation improves a lot how bonobo works, even if this is
highly backward incompatible (sorry, that's needed, and better sooner
than later).

* New implementation uses the same approach as python's namedtuple,
  by dynamically creating the python type's code. This has drawbacks, as
  it feels like not the right way, but also a lot of benefits that
  cannot be achieved using a regular approach, especially the
  constructor parameter order, hardcoded.
* Memory usage is now much more efficient. The "keys" memory space will
  be used only once per "io type", being spent in the underlying type
  definition instead of in the actual instances.
* Transformations now needs to use tuples as output, which will be bound
  to its "output type". The output type can be infered from the tuple
  length, or explicitely set by the user using either
  `context.set_output_type(...)` or `context.set_output_fields(...)` (to
  build a bag type from a list of field names).

Jupyter/Graphviz integration is more tight, allowing to easily display
graphs in a notebook, or displaying the live transformation status in an
html table instead of a simple <div>.

For now, context processors were hacked to stay working as before but
the current API is not satisfactory, and should be replaced. This new
big change being unreasonable without some time to work on it properly,
it is postponed for next versions (0.7, 0.8, ...). Maybe the best idea
is to have some kind of "local services", that would use the same
dependency injection mechanism as the execution-wide services.

Services are now passed by keywoerd arguments only, to avoid confusion
with data-arguments.
This commit is contained in:
Romain Dorgueil
2017-11-27 00:04:51 +01:00
parent 52ea29afcb
commit 5e0b6567cd
96 changed files with 2958 additions and 1870 deletions

View File

@ -1,62 +1,152 @@
from collections import namedtuple
from unittest import TestCase
import pytest
from bonobo import CsvReader, CsvWriter, settings
from bonobo.execution.contexts.node import NodeExecutionContext
from bonobo.util.testing import FilesystemTester, BufferingNodeExecutionContext
from bonobo import CsvReader, CsvWriter
from bonobo.constants import EMPTY
from bonobo.util.testing import FilesystemTester, BufferingNodeExecutionContext, WriterTest, ConfigurableNodeTest, ReaderTest
csv_tester = FilesystemTester('csv')
csv_tester.input_data = 'a,b,c\na foo,b foo,c foo\na bar,b bar,c bar'
defaults = {'lineterminator': '\n'}
def test_write_csv_ioformat_arg0(tmpdir):
fs, filename, services = csv_tester.get_services_for_writer(tmpdir)
with pytest.raises(ValueError):
CsvWriter(path=filename, ioformat=settings.IOFORMAT_ARG0)
with pytest.raises(ValueError):
CsvReader(path=filename, delimiter=',', ioformat=settings.IOFORMAT_ARG0),
def test_write_csv_to_file_no_headers(tmpdir):
fs, filename, services = csv_tester.get_services_for_writer(tmpdir)
with NodeExecutionContext(CsvWriter(filename), services=services) as context:
context.write_sync(('bar', ), ('baz', 'boo'))
with fs.open(filename) as fp:
assert fp.read() == 'bar\nbaz;boo\n'
def test_write_csv_to_file_with_headers(tmpdir):
fs, filename, services = csv_tester.get_services_for_writer(tmpdir)
with NodeExecutionContext(CsvWriter(filename, headers='foo'), services=services) as context:
context.write_sync(('bar', ), ('baz', 'boo'))
with fs.open(filename) as fp:
assert fp.read() == 'foo\nbar\nbaz\n'
with pytest.raises(AttributeError):
getattr(context, 'file')
incontext = ConfigurableNodeTest.incontext
def test_read_csv_from_file_kwargs(tmpdir):
fs, filename, services = csv_tester.get_services_for_reader(tmpdir)
with BufferingNodeExecutionContext(
CsvReader(path=filename, delimiter=','),
services=services,
) as context:
context.write_sync(())
with BufferingNodeExecutionContext(CsvReader(filename, **defaults), services=services) as context:
context.write_sync(EMPTY)
assert context.get_buffer_args_as_dicts() == [
{
'a': 'a foo',
'b': 'b foo',
'c': 'c foo',
}, {
'a': 'a bar',
'b': 'b bar',
'c': 'c bar',
}
]
assert context.get_buffer_args_as_dicts() == [{
'a': 'a foo',
'b': 'b foo',
'c': 'c foo',
}, {
'a': 'a bar',
'b': 'b bar',
'c': 'c bar',
}]
###
# CSV Readers / Writers
###
class Csv:
extension = 'csv'
ReaderNodeType = CsvReader
WriterNodeType = CsvWriter
L1, L2, L3, L4 = ('a', 'hey'), ('b', 'bee'), ('c', 'see'), ('d', 'dee')
LL = ('i', 'have', 'more', 'values')
class CsvReaderTest(Csv, ReaderTest, TestCase):
input_data = '\n'.join((
'id,name',
'1,John Doe',
'2,Jane Doe',
',DPR',
'42,Elon Musk',
))
def check_output(self, context, *, prepend=None):
out = context.get_buffer()
assert out == (prepend or list()) + [
('1', 'John Doe'),
('2', 'Jane Doe'),
('', 'DPR'),
('42', 'Elon Musk'),
]
@incontext()
def test_nofields(self, context):
context.write_sync(EMPTY)
context.stop()
self.check_output(context)
assert context.get_output_fields() == ('id', 'name')
@incontext(output_type=tuple)
def test_output_type(self, context):
context.write_sync(EMPTY)
context.stop()
self.check_output(context, prepend=[('id', 'name')])
@incontext(
output_fields=(
'x',
'y',
), skip=1
)
def test_output_fields(self, context):
context.write_sync(EMPTY)
context.stop()
self.check_output(context)
assert context.get_output_fields() == ('x', 'y')
class CsvWriterTest(Csv, WriterTest, TestCase):
@incontext()
def test_fields(self, context):
context.set_input_fields(['foo', 'bar'])
context.write_sync(('a', 'b'), ('c', 'd'))
context.stop()
assert self.readlines() == (
'foo,bar',
'a,b',
'c,d',
)
@incontext()
def test_fields_from_type(self, context):
context.set_input_type(namedtuple('Point', 'x y'))
context.write_sync((1, 2), (3, 4))
context.stop()
assert self.readlines() == ('x,y', '1,2', '3,4')
@incontext()
def test_nofields_multiple_args(self, context):
# multiple args are iterated onto and flattened in output
context.write_sync((L1, L2), (L3, L4))
context.stop()
assert self.readlines() == (
'a,hey',
'b,bee',
'c,see',
'd,dee',
)
@incontext()
def test_nofields_multiple_args_length_mismatch(self, context):
# if length of input vary, then we get a TypeError (unrecoverable)
with pytest.raises(TypeError):
context.write_sync((L1, L2), (L3, ))
@incontext()
def test_nofields_single_arg(self, context):
# single args are just dumped, shapes can vary.
context.write_sync((L1, ), (LL, ), (L3, ))
context.stop()
assert self.readlines() == (
'a,hey',
'i,have,more,values',
'c,see',
)
@incontext()
def test_nofields_empty_args(self, context):
# empty calls are ignored
context.write_sync(EMPTY, EMPTY, EMPTY)
context.stop()
assert self.readlines() == ()

View File

@ -1,7 +1,7 @@
import pytest
from bonobo import Bag, FileReader, FileWriter
from bonobo.constants import BEGIN, END
from bonobo import FileReader, FileWriter
from bonobo.constants import EMPTY
from bonobo.execution.contexts.node import NodeExecutionContext
from bonobo.util.testing import BufferingNodeExecutionContext, FilesystemTester
@ -30,9 +30,7 @@ def test_file_writer_in_context(tmpdir, lines, output):
fs, filename, services = txt_tester.get_services_for_writer(tmpdir)
with NodeExecutionContext(FileWriter(path=filename), services=services) as context:
context.write(BEGIN, *map(Bag, lines), END)
for _ in range(len(lines)):
context.step()
context.write_sync(*lines)
with fs.open(filename) as fp:
assert fp.read() == output
@ -42,9 +40,9 @@ def test_file_reader(tmpdir):
fs, filename, services = txt_tester.get_services_for_reader(tmpdir)
with BufferingNodeExecutionContext(FileReader(path=filename), services=services) as context:
context.write_sync(Bag())
output = context.get_buffer()
context.write_sync(EMPTY)
output = context.get_buffer()
assert len(output) == 2
assert output[0] == 'Hello'
assert output[1] == 'World'
assert output[0] == ('Hello', )
assert output[1] == ('World', )

View File

@ -1,66 +1,300 @@
import json
from collections import OrderedDict, namedtuple
from unittest import TestCase
import pytest
from bonobo import JsonReader, JsonWriter, settings
from bonobo import JsonReader, JsonWriter
from bonobo import LdjsonReader, LdjsonWriter
from bonobo.execution.contexts.node import NodeExecutionContext
from bonobo.util.testing import FilesystemTester, BufferingNodeExecutionContext
from bonobo.constants import EMPTY
from bonobo.util.testing import WriterTest, ReaderTest, ConfigurableNodeTest
json_tester = FilesystemTester('json')
json_tester.input_data = '''[{"x": "foo"},{"x": "bar"}]'''
FOOBAR = {'foo': 'bar'}
OD_ABC = OrderedDict((('a', 'A'), ('b', 'B'), ('c', 'C')))
FOOBAZ = {'foo': 'baz'}
incontext = ConfigurableNodeTest.incontext
###
# Standard JSON Readers / Writers
###
def test_write_json_ioformat_arg0(tmpdir):
fs, filename, services = json_tester.get_services_for_writer(tmpdir)
with pytest.raises(ValueError):
JsonWriter(filename, ioformat=settings.IOFORMAT_ARG0)
with pytest.raises(ValueError):
JsonReader(filename, ioformat=settings.IOFORMAT_ARG0),
class Json:
extension = 'json'
ReaderNodeType = JsonReader
WriterNodeType = JsonWriter
@pytest.mark.parametrize('add_kwargs', (
{},
{
'ioformat': settings.IOFORMAT_KWARGS,
},
))
def test_write_json_kwargs(tmpdir, add_kwargs):
fs, filename, services = json_tester.get_services_for_writer(tmpdir)
class JsonReaderDictsTest(Json, ReaderTest, TestCase):
input_data = '[{"foo": "bar"},\n{"baz": "boz"}]'
with NodeExecutionContext(JsonWriter(filename, **add_kwargs), services=services) as context:
context.write_sync({'foo': 'bar'})
@incontext()
def test_nofields(self, context):
context.write_sync(EMPTY)
context.stop()
with fs.open(filename) as fp:
assert fp.read() == '[{"foo": "bar"}]'
assert context.get_buffer() == [
({
"foo": "bar"
}, ),
({
"baz": "boz"
}, ),
]
stream_json_tester = FilesystemTester('json')
stream_json_tester.input_data = '''{"foo": "bar"}\n{"baz": "boz"}'''
class JsonReaderListsTest(Json, ReaderTest, TestCase):
input_data = '[[1,2,3],\n[4,5,6]]'
@incontext()
def test_nofields(self, context):
context.write_sync(EMPTY)
context.stop()
assert context.get_buffer() == [
([1, 2, 3], ),
([4, 5, 6], ),
]
@incontext(output_type=tuple)
def test_output_type(self, context):
context.write_sync(EMPTY)
context.stop()
assert context.get_buffer() == [
([1, 2, 3], ),
([4, 5, 6], ),
]
def test_read_stream_json(tmpdir):
fs, filename, services = stream_json_tester.get_services_for_reader(tmpdir)
with BufferingNodeExecutionContext(LdjsonReader(filename), services=services) as context:
context.write_sync(tuple())
actual = context.get_buffer()
class JsonReaderStringsTest(Json, ReaderTest, TestCase):
input_data = '[' + ',\n'.join(map(json.dumps, ('foo', 'bar', 'baz'))) + ']'
expected = [{"foo": "bar"}, {"baz": "boz"}]
assert expected == actual
@incontext()
def test_nofields(self, context):
context.write_sync(EMPTY)
context.stop()
assert context.get_buffer() == [
('foo', ),
('bar', ),
('baz', ),
]
@incontext(output_type=tuple)
def test_output_type(self, context):
context.write_sync(EMPTY)
context.stop()
assert context.get_buffer() == [
('foo', ),
('bar', ),
('baz', ),
]
def test_write_stream_json(tmpdir):
fs, filename, services = stream_json_tester.get_services_for_reader(tmpdir)
class JsonWriterTest(Json, WriterTest, TestCase):
@incontext()
def test_fields(self, context):
context.set_input_fields(['foo', 'bar'])
context.write_sync(('a', 'b'), ('c', 'd'))
context.stop()
with BufferingNodeExecutionContext(LdjsonWriter(filename), services=services) as context:
context.write_sync(
{
'foo': 'bar'
},
{'baz': 'boz'},
assert self.readlines() == (
'[{"foo": "a", "bar": "b"},',
'{"foo": "c", "bar": "d"}]',
)
expected = '''{"foo": "bar"}\n{"baz": "boz"}\n'''
with fs.open(filename) as fin:
actual = fin.read()
assert expected == actual
@incontext()
def test_fields_from_type(self, context):
context.set_input_type(namedtuple('Point', 'x y'))
context.write_sync((1, 2), (3, 4))
context.stop()
assert self.readlines() == (
'[{"x": 1, "y": 2},',
'{"x": 3, "y": 4}]',
)
@incontext()
def test_nofields_multiple_args(self, context):
# multiple args are iterated onto and flattened in output
context.write_sync((FOOBAR, FOOBAR), (OD_ABC, FOOBAR), (FOOBAZ, FOOBAR))
context.stop()
assert self.readlines() == (
'[{"foo": "bar"},',
'{"foo": "bar"},',
'{"a": "A", "b": "B", "c": "C"},',
'{"foo": "bar"},',
'{"foo": "baz"},',
'{"foo": "bar"}]',
)
@incontext()
def test_nofields_multiple_args_length_mismatch(self, context):
# if length of input vary, then we get a TypeError (unrecoverable)
with pytest.raises(TypeError):
context.write_sync((FOOBAR, FOOBAR), (OD_ABC))
@incontext()
def test_nofields_single_arg(self, context):
# single args are just dumped, shapes can vary.
context.write_sync(FOOBAR, OD_ABC, FOOBAZ)
context.stop()
assert self.readlines() == (
'[{"foo": "bar"},',
'{"a": "A", "b": "B", "c": "C"},',
'{"foo": "baz"}]',
)
@incontext()
def test_nofields_empty_args(self, context):
# empty calls are ignored
context.write_sync(EMPTY, EMPTY, EMPTY)
context.stop()
assert self.readlines() == ('[]', )
###
# Line Delimiter JSON Readers / Writers
###
class Ldjson:
extension = 'ldjson'
ReaderNodeType = LdjsonReader
WriterNodeType = LdjsonWriter
class LdjsonReaderDictsTest(Ldjson, ReaderTest, TestCase):
input_data = '{"foo": "bar"}\n{"baz": "boz"}'
@incontext()
def test_nofields(self, context):
context.write_sync(EMPTY)
context.stop()
assert context.get_buffer() == [
({
"foo": "bar"
}, ),
({
"baz": "boz"
}, ),
]
class LdjsonReaderListsTest(Ldjson, ReaderTest, TestCase):
input_data = '[1,2,3]\n[4,5,6]'
@incontext()
def test_nofields(self, context):
context.write_sync(EMPTY)
context.stop()
assert context.get_buffer() == [
([1, 2, 3], ),
([4, 5, 6], ),
]
@incontext(output_type=tuple)
def test_output_type(self, context):
context.write_sync(EMPTY)
context.stop()
assert context.get_buffer() == [
([1, 2, 3], ),
([4, 5, 6], ),
]
class LdjsonReaderStringsTest(Ldjson, ReaderTest, TestCase):
input_data = '\n'.join(map(json.dumps, ('foo', 'bar', 'baz')))
@incontext()
def test_nofields(self, context):
context.write_sync(EMPTY)
context.stop()
assert context.get_buffer() == [
('foo', ),
('bar', ),
('baz', ),
]
@incontext(output_type=tuple)
def test_output_type(self, context):
context.write_sync(EMPTY)
context.stop()
assert context.get_buffer() == [
('foo', ),
('bar', ),
('baz', ),
]
class LdjsonWriterTest(Ldjson, WriterTest, TestCase):
@incontext()
def test_fields(self, context):
context.set_input_fields(['foo', 'bar'])
context.write_sync(('a', 'b'), ('c', 'd'))
context.stop()
assert self.readlines() == ('{"foo": "a", "bar": "b"}', '{"foo": "c", "bar": "d"}')
@incontext()
def test_fields_from_type(self, context):
context.set_input_type(namedtuple('Point', 'x y'))
context.write_sync((1, 2), (3, 4))
context.stop()
assert self.readlines() == (
'{"x": 1, "y": 2}',
'{"x": 3, "y": 4}',
)
@incontext()
def test_nofields_multiple_args(self, context):
# multiple args are iterated onto and flattened in output
context.write_sync((FOOBAR, FOOBAR), (OD_ABC, FOOBAR), (FOOBAZ, FOOBAR))
context.stop()
assert self.readlines() == (
'{"foo": "bar"}',
'{"foo": "bar"}',
'{"a": "A", "b": "B", "c": "C"}',
'{"foo": "bar"}',
'{"foo": "baz"}',
'{"foo": "bar"}',
)
@incontext()
def test_nofields_multiple_args_length_mismatch(self, context):
# if length of input vary, then we get a TypeError (unrecoverable)
with pytest.raises(TypeError):
context.write_sync((FOOBAR, FOOBAR), (OD_ABC))
@incontext()
def test_nofields_single_arg(self, context):
# single args are just dumped, shapes can vary.
context.write_sync(FOOBAR, OD_ABC, FOOBAZ)
context.stop()
assert self.readlines() == (
'{"foo": "bar"}',
'{"a": "A", "b": "B", "c": "C"}',
'{"foo": "baz"}',
)
@incontext()
def test_nofields_empty_args(self, context):
# empty calls are ignored
context.write_sync(EMPTY, EMPTY, EMPTY)
context.stop()
assert self.readlines() == ()

View File

@ -2,7 +2,8 @@ import pickle
import pytest
from bonobo import Bag, PickleReader, PickleWriter
from bonobo import PickleReader, PickleWriter
from bonobo.constants import EMPTY
from bonobo.execution.contexts.node import NodeExecutionContext
from bonobo.util.testing import BufferingNodeExecutionContext, FilesystemTester
@ -14,7 +15,7 @@ def test_write_pickled_dict_to_file(tmpdir):
fs, filename, services = pickle_tester.get_services_for_writer(tmpdir)
with NodeExecutionContext(PickleWriter(filename), services=services) as context:
context.write_sync(Bag(({'foo': 'bar'}, {})), Bag(({'foo': 'baz', 'ignore': 'this'}, {})))
context.write_sync({'foo': 'bar'}, {'foo': 'baz', 'ignore': 'this'})
with fs.open(filename, 'rb') as fp:
assert pickle.loads(fp.read()) == {'foo': 'bar'}
@ -27,17 +28,11 @@ def test_read_pickled_list_from_file(tmpdir):
fs, filename, services = pickle_tester.get_services_for_reader(tmpdir)
with BufferingNodeExecutionContext(PickleReader(filename), services=services) as context:
context.write_sync(())
output = context.get_buffer()
context.write_sync(EMPTY)
assert len(output) == 2
assert output[0] == {
'a': 'a foo',
'b': 'b foo',
'c': 'c foo',
}
assert output[1] == {
'a': 'a bar',
'b': 'b bar',
'c': 'c bar',
}
output = context.get_buffer()
assert context.get_output_fields() == ('a', 'b', 'c')
assert output == [
('a foo', 'b foo', 'c foo'),
('a bar', 'b bar', 'c bar'),
]

View File

@ -1,64 +1,79 @@
from operator import methodcaller
from unittest import TestCase
from unittest.mock import MagicMock
import pytest
import bonobo
from bonobo.config.processors import ContextCurrifier
from bonobo.constants import NOT_MODIFIED
from bonobo.util.testing import BufferingNodeExecutionContext
from bonobo.constants import NOT_MODIFIED, EMPTY
from bonobo.util import ensure_tuple, ValueHolder
from bonobo.util.testing import BufferingNodeExecutionContext, StaticNodeTest, ConfigurableNodeTest
def test_count():
with pytest.raises(TypeError):
bonobo.count()
class CountTest(StaticNodeTest, TestCase):
node = bonobo.count
context = MagicMock()
def test_counter_required(self):
with pytest.raises(TypeError):
self.call()
with ContextCurrifier(bonobo.count).as_contextmanager(context) as stack:
for i in range(42):
stack()
def test_manual_call(self):
counter = ValueHolder(0)
for i in range(3):
self.call(counter)
assert counter == 3
assert len(context.method_calls) == 1
bag = context.send.call_args[0][0]
assert isinstance(bag, bonobo.Bag)
assert 0 == len(bag.kwargs)
assert 1 == len(bag.args)
assert bag.args[0] == 42
def test_execution(self):
with self.execute() as context:
context.write_sync(*([EMPTY] * 42))
assert context.get_buffer() == [(42, )]
def test_identity():
assert bonobo.identity(42) == 42
class IdentityTest(StaticNodeTest, TestCase):
node = bonobo.identity
def test_basic_call(self):
assert self.call(42) == 42
def test_execution(self):
object_list = [object() for _ in range(42)]
with self.execute() as context:
context.write_sync(*object_list)
assert context.get_buffer() == list(map(ensure_tuple, object_list))
def test_limit():
context, results = MagicMock(), []
class LimitTest(ConfigurableNodeTest, TestCase):
@classmethod
def setUpClass(cls):
cls.NodeType = bonobo.Limit
with ContextCurrifier(bonobo.Limit(2)).as_contextmanager(context) as stack:
for i in range(42):
results += list(stack())
def test_execution_default(self):
object_list = [object() for _ in range(42)]
with self.execute() as context:
context.write_sync(*object_list)
assert results == [NOT_MODIFIED] * 2
assert context.get_buffer() == list(map(ensure_tuple, object_list[:10]))
def test_execution_custom(self):
object_list = [object() for _ in range(42)]
with self.execute(21) as context:
context.write_sync(*object_list)
def test_limit_not_there():
context, results = MagicMock(), []
assert context.get_buffer() == list(map(ensure_tuple, object_list[:21]))
with ContextCurrifier(bonobo.Limit(42)).as_contextmanager(context) as stack:
for i in range(10):
results += list(stack())
def test_manual(self):
limit = self.NodeType(5)
buffer = []
for x in range(10):
buffer += list(limit(x))
assert len(buffer) == 5
assert results == [NOT_MODIFIED] * 10
def test_limit_default():
context, results = MagicMock(), []
with ContextCurrifier(bonobo.Limit()).as_contextmanager(context) as stack:
for i in range(20):
results += list(stack())
assert results == [NOT_MODIFIED] * 10
def test_underflow(self):
limit = self.NodeType(10)
buffer = []
for x in range(5):
buffer += list(limit(x))
assert len(buffer) == 5
def test_tee():
@ -76,36 +91,28 @@ def test_noop():
assert bonobo.noop(1, 2, 3, 4, foo='bar') == NOT_MODIFIED
def test_update():
with BufferingNodeExecutionContext(bonobo.Update('a', k=True)) as context:
context.write_sync('a', ('a', {'b': 1}), ('b', {'k': False}))
assert context.get_buffer() == [
bonobo.Bag('a', 'a', k=True),
bonobo.Bag('a', 'a', b=1, k=True),
bonobo.Bag('b', 'a', k=True),
]
assert context.name == "Update('a', k=True)"
def test_fixedwindow():
with BufferingNodeExecutionContext(bonobo.FixedWindow(2)) as context:
context.write_sync(*range(10))
assert context.get_buffer() == [[0, 1], [2, 3], [4, 5], [6, 7], [8, 9]]
assert context.get_buffer() == [(0, 1), (2, 3), (4, 5), (6, 7), (8, 9)]
with BufferingNodeExecutionContext(bonobo.FixedWindow(2)) as context:
context.write_sync(*range(9))
assert context.get_buffer() == [[0, 1], [2, 3], [4, 5], [6, 7], [8]]
assert context.get_buffer() == [(0, 1), (2, 3), (4, 5), (6, 7), (
8,
None,
)]
with BufferingNodeExecutionContext(bonobo.FixedWindow(1)) as context:
context.write_sync(*range(3))
assert context.get_buffer() == [[0], [1], [2]]
assert context.get_buffer() == [(0, ), (1, ), (2, )]
def test_methodcaller():
with BufferingNodeExecutionContext(methodcaller('swapcase')) as context:
context.write_sync('aaa', 'bBb', 'CcC')
assert context.get_buffer() == ['AAA', 'BbB', 'cCc']
assert context.get_buffer() == list(map(ensure_tuple, ['AAA', 'BbB', 'cCc']))
with BufferingNodeExecutionContext(methodcaller('zfill', 5)) as context:
context.write_sync('a', 'bb', 'ccc')
assert context.get_buffer() == ['0000a', '000bb', '00ccc']
assert context.get_buffer() == list(map(ensure_tuple, ['0000a', '000bb', '00ccc']))