Create v2 that is compatible with Core v2 (#21)

* Create v2 that is compatible with Core v2

* Bump version to 2.0
* Support GraphQL-core >= 2.0, < 3
  (use the newer signature for resolvers)
* Drop support for Python 3.3
* Drop redundant README.rst
* Clean-up and PEP-8
* Use .flake8 instead of setup.cfg
* Use "setup.py test" for testing, as explained in README
* Make this run with pytest 4. This will be changed in v3,
  where we use pytest 5 and run it directly.
* Only check relevant files with flake8
* Minor fixes in the README

Author: Cito

Diff for: .flake8

@@ -0,0 +1,4 @@
+[flake8]
+ignore = E203,W503,E704
+exclude = .git,.mypy_cache,.pytest_cache,.tox,.venv,__pycache__,build,dist,docs
+max-line-length = 88

Diff for: .gitignore

@@ -1,16 +1,7 @@
-# Created by https://www.gitignore.io
-
-### Python ###
-# Byte-compiled / optimized / DLL files
 __pycache__/
 *.py[cod]
 
-# C extensions
-*.so
-
-# Distribution / packaging
 .Python
-env/
 build/
 develop-eggs/
 dist/
@@ -22,40 +13,50 @@ lib64/
 parts/
 sdist/
 var/
+wheels/
+pip-wheel-metadata/
+share/python-wheels/
 *.egg-info/
 .installed.cfg
 *.egg
+MANIFEST
 
-# PyInstaller
-#  Usually these files are written by a python script from a template
-#  before PyInstaller builds the exe, so as to inject date/other infos into it.
 *.manifest
 *.spec
 
-# Installer logs
 pip-log.txt
 pip-delete-this-directory.txt
 
-# Unit test / coverage reports
 htmlcov/
 .tox/
+.nox/
 .coverage
 .coverage.*
 .cache
 nosetests.xml
 coverage.xml
-*,cover
+*.cover
+.pytest_cache/
 
-# Translations
 *.mo
 *.pot
 
-# Django stuff:
 *.log
 
-# Sphinx documentation
 docs/_build/
 
-# PyBuilder
 target/
 
+.python-version
+
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+
+.mypy_cache/
+
+.idea/

Diff for: .travis.yml

@@ -2,17 +2,17 @@ language: python
 dist: xenial
 
 python:
-  - 2.7
-  - 3.5
-  - 3.6
-  - 3.7
-  - pypy3
+  - "2.7"
+  - "3.5"
+  - "3.6"
+  - "3.7"
+  - "pypy3"
 install:
-  - pip install pytest pytest-cov flake8
   - pip install .
+  - pip install "flake8>=3.7,<4"
 script:
-  - py.test --cov=graphql_relay
-# - flake8
+  - python setup.py test -a "--cov=graphql_relay"
+  - flake8 setup.py src tests
 after_success:
   - pip install coveralls
   - coveralls

Diff for: README.md

@@ -36,7 +36,7 @@ that documentation and the corresponding tests in this library together.
 Install Relay Library for GraphQL Python
 
 ```sh
-pip install graphql-core --pre # Last version of graphql-core
+pip install "graphql-core>=2,<3" # use version 2.x of graphql-core
 pip install graphql-relay
 ```
 
@@ -54,13 +54,13 @@ returning those types.
 they return a connection type.
  - `connection_definitions` returns a `connection_type` and its associated
 `edgeType`, given a name and a node type.
- - `connection_from_list` is a helper method that takes an array and the
+ - `connection_from_list` is a helper method that takes a list and the
 arguments from `connection_args`, does pagination and filtering, and returns
 an object in the shape expected by a `connection_type`'s `resolver` function.
  - `connection_from_promised_list` is similar to `connection_from_list`, but
 it takes a promise that resolves to an array, and returns a promise that
 resolves to the expected shape by `connection_type`.
- - `cursor_for_object_in_connection` is a helper method that takes an array and a
+ - `cursor_for_object_in_connection` is a helper method that takes a list and a
 member object, and returns a cursor for use in the mutation payload.
 
 An example usage of these methods from the [test schema](tests/starwars/schema.py):
@@ -69,32 +69,31 @@ An example usage of these methods from the [test schema](tests/starwars/schema.p
 ship_edge, ship_connection = connection_definitions('Ship', shipType)
 
 factionType = GraphQLObjectType(
-    name= 'Faction',
-    description= 'A faction in the Star Wars saga',
+    name='Faction',
+    description='A faction in the Star Wars saga',
     fields= lambda: {
         'id': global_id_field('Faction'),
         'name': GraphQLField(
             GraphQLString,
             description='The name of the faction.',
         ),
         'ships': GraphQLField(
-            shipConnection,
-            description= 'The ships used by the faction.',
-            args= connection_args,
-            resolver= lambda faction, args, *_: connection_from_list(
-                map(getShip, faction.ships),
-                args
+            ship_connection,
+            description='The ships used by the faction.',
+            args=connection_args,
+            resolver=lambda faction, _info, **args: connection_from_list(
+                [getShip(ship) for ship in faction.ships], args
             ),
         )
     },
-    interfaces= [node_interface]
+    interfaces=[node_interface]
 )
 ```
 
 This shows adding a `ships` field to the `Faction` object that is a connection.
 It uses `connection_definitions({name: 'Ship', nodeType: shipType})` to create
 the connection type, adds `connection_args` as arguments on this function, and
-then implements the resolver function by passing the array of ships and the
+then implements the resolver function by passing the list of ships and the
 arguments to `connection_from_list`.
 
 ### Object Identification
@@ -108,7 +107,7 @@ this, it takes a function to resolve an ID to an object, and to determine
 the type of a given object.
  - `to_global_id` takes a type name and an ID specific to that type name,
 and returns a "global ID" that is unique among all types.
- - `from_global_id` takes the "global ID" created by `toGlobalID`, and retuns
+ - `from_global_id` takes the "global ID" created by `to_global_id`, and returns
 the type name and ID used to create it.
  - `global_id_field` creates the configuration for an `id` field on a node.
  - `plural_identifying_root_field` creates a field that accepts a list of
@@ -118,17 +117,16 @@ objects.
 An example usage of these methods from the [test schema](tests/starwars/schema.py):
 
 ```python
-def get_node(global_id, context, info):
-    resolvedGlobalId = from_global_id(global_id)
-    _type, _id = resolvedGlobalId.type, resolvedGlobalId.id
-    if _type == 'Faction':
-        return getFaction(_id)
-    elif _type == 'Ship':
-        return getShip(_id)
+def get_node(global_id, _info):
+    type_, id_ = from_global_id(global_id)
+    if type_ == 'Faction':
+        return getFaction(id_)
+    elif type_ == 'Ship':
+        return getShip(id_)
     else:
         return None
 
-def get_node_type(obj, context, info):
+def get_node_type(obj, _info):
     if isinstance(obj, Faction):
         return factionType
     else:
@@ -177,11 +175,9 @@ class IntroduceShipMutation(object):
     def __init__(self, shipId, factionId, clientMutationId=None):
         self.shipId = shipId
         self.factionId = factionId
-        self.clientMutationId = None
+        self.clientMutationId = clientMutationId
 
-def mutate_and_get_payload(data, *_):
-    shipName = data.get('shipName')
-    factionId = data.get('factionId')
+def mutate_and_get_payload(_info, shipName, factionId, **_input):
     newShip = createShip(shipName, factionId)
     return IntroduceShipMutation(
         shipId=newShip.id,
@@ -201,19 +197,19 @@ shipMutation = mutation_with_client_mutation_id(
     output_fields= {
         'ship': GraphQLField(
             shipType,
-            resolver= lambda payload, *_: getShip(payload.shipId)
+            resolver=lambda payload, _info: getShip(payload.shipId)
         ),
         'faction': GraphQLField(
             factionType,
-            resolver= lambda payload, *_: getFaction(payload.factionId)
+            resolver=lambda payload, _info: getFaction(payload.factionId)
         )
     },
     mutate_and_get_payload=mutate_and_get_payload
 )
 
 mutationType = GraphQLObjectType(
     'Mutation',
-    fields= lambda: {
+    fields=lambda: {
         'introduceShip': shipMutation
     }
 )