[core] Still refactoring the core behaviour of bags, starting to be much simpler.

tests/io/test_csv.py

@@ -28,9 +28,7 @@ def test_write_csv_to_file_kwargs(tmpdir, add_kwargs):
     fs, filename, services = csv_tester.get_services_for_writer(tmpdir)
 
     with NodeExecutionContext(CsvWriter(filename, **add_kwargs), services=services) as context:
-        context.write(BEGIN, Bag(**{'foo': 'bar'}), Bag(**{'foo': 'baz', 'ignore': 'this'}), END)
-        context.step()
-        context.step()
+        context.write_sync({'foo': 'bar'}, {'foo': 'baz', 'ignore': 'this'})
 
     with fs.open(filename) as fp:
         assert fp.read() == 'foo\nbar\nbaz\n'

tests/io/test_json.py

@@ -1,7 +1,6 @@
 import pytest
 
-from bonobo import Bag, JsonReader, JsonWriter, settings
-from bonobo.constants import BEGIN, END
+from bonobo import JsonReader, JsonWriter, settings
 from bonobo.execution.node import NodeExecutionContext
 from bonobo.util.testing import FilesystemTester
 
@@ -29,8 +28,7 @@ def test_write_json_kwargs(tmpdir, add_kwargs):
     fs, filename, services = json_tester.get_services_for_writer(tmpdir)
 
     with NodeExecutionContext(JsonWriter(filename, **add_kwargs), services=services) as context:
-        context.write(BEGIN, Bag(**{'foo': 'bar'}), END)
-        context.step()
+        context.write_sync({'foo': 'bar'})
 
     with fs.open(filename) as fp:
         assert fp.read() == '[{"foo": "bar"}]'

tests/io/test_pickle.py

@@ -14,7 +14,7 @@ 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(Bag(({'foo': 'bar'}, {})), Bag(({'foo': 'baz', 'ignore': 'this'}, {})))
 
     with fs.open(filename, 'rb') as fp:
         assert pickle.loads(fp.read()) == {'foo': 'bar'}
@@ -27,7 +27,7 @@ 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(Bag())
+        context.write_sync(())
         output = context.get_buffer()
 
     assert len(output) == 2