Add sync batching to requests sync transport

[itolosa]

Feature

Enable batching.

It adds execute_batch method for Transport and Client in order to allow users to send multiple requests at once.

Server must allow this type of requests.

Issue: #430

Resources:

• https://github.com/graphql/graphql-over-http/blob/main/rfcs/Batching.md
• https://spec.graphql.org/October2021

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (013fa6a) 100.00% compared to head (1e4c981) 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##            master      #431    +/-   ##
==========================================
  Coverage   100.00%   100.00%            
==========================================
  Files           27        28     +1     
  Lines         2388      2492   +104     
==========================================
+ Hits          2388      2492   +104     

Files Changed	Coverage Δ
gql/transport/aiohttp.py	100.00% <ø> (ø)
gql/__init__.py	100.00% <100.00%> (ø)
gql/client.py	100.00% <100.00%> (ø)
gql/graphql_request.py	100.00% <100.00%> (ø)
gql/transport/requests.py	100.00% <100.00%> (ø)
gql/transport/transport.py	100.00% <100.00%> (ø)

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[itolosa]

No clue why some tests are failing because of some missing aiohttp. It just happens on the CI

Edited: Because of some missing test marks

[leszekhanusz]

No clue why some tests are failing because of some missing aiohttp. It just happens on the CI

In the CI, we are testing that some tests are supposed to work only with a single transport dependency installed.

If you run pytest tests --requests-only, it should work even if aiohttp is not installed (after running pip uninstall aiohttp)

It is possible to mark the tests to specify which test can be run in which condition. But I just see that you found out about it just now.

[leszekhanusz]

This look good already!
Also nice to see that the countries.trevorblades.com site we use for our tests supports batch requests.
I've noted a few requested changes.
If you could also please check again all the docstrings so that the parameters correspond to the new ones and the text is modified to say that it's a batch operation.
Thanks!

[itolosa]

Pushed some fixes

[leszekhanusz]

a few nitpicking changes.

[leszekhanusz]

LGTM

[itolosa]

Nice work! 😄

[leszekhanusz]

Thanks for your help!