Allow class member values in projection and distinct queries

[chmoder]

Fixes#212 by setting the projection and distinct_on lists to their string type names. Before it converted them but did not set them.

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[chmoder]

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[crwilcox]

@chmoder it seems that a unit test is failing currently

__________ TestQuery.test_constructor_with_class_attribute_projection __________
args = (<MagicMock name='_datastore_query' id='140197655604192'>,)
keywargs = {}
extra_args = [<MagicMock name='_datastore_query' id='140197655604192'>]
entered_patchers = [<unittest.mock._patch object at 0x7f824fab6ac8>]
exc_info = (<class 'TypeError'>, TypeError('test_constructor_with_class_attribute_projection() takes 0 positional arguments but 1 was given',), <traceback object at 0x7f82504ff808>)
patching = <unittest.mock._patch object at 0x7f824fab6ac8>
arg = <MagicMock name='_datastore_query' id='140197655604192'>
@wraps(func)
def patched(*args, **keywargs):
extra_args = []
entered_patchers = []
exc_info = tuple()
try:
for patching in patched.patchings:
arg = patching.__enter__()
entered_patchers.append(patching)
if patching.attribute_name is not None:
keywargs.update(arg)
elif patching.new is DEFAULT:
extra_args.append(arg)
args += tuple(extra_args)
> return func(*args, **keywargs)
E TypeError: test_constructor_with_class_attribute_projection() takes 0 positional arguments but 1 was given

[chmoder]

@crwilcox, thank you. I have pushed changes to fix that along with a new test case to test distinct_on with a projection.

[chrisrossi]

This looks great, thank you! I will merge once Kokoro awakens from its stupor and runs the tests.

[chmoder]

@chrisrossi ,

Thanks Chris! I noticed the build failed due to lint checking. I ran black with kokoros build configuration and pushed that up as well.

[chrisrossi]

Yep, I was in the middle of writing a not about how to use "nox" to run "blacken" when you pushed that and made my note obsolete. Thanks!

[chrisrossi]

Thank you for your bugfix @chmoder !