Added experimental dataloader

Author: syrusakbary

graphql/execution/tests/test_dataloader.py

@@ -0,0 +1,142 @@
+from promise import Promise
+from promise.dataloader import DataLoader
+
+from graphql import GraphQLObjectType, GraphQLField, GraphQLID, GraphQLArgument, GraphQLNonNull, GraphQLSchema, parse, execute
+
+
+def test_batches_correctly():
+
+    Business = GraphQLObjectType('Business', lambda: {
+        'id': GraphQLField(GraphQLID, resolver=lambda root, args, context, info: root),
+    })
+
+    Query = GraphQLObjectType('Query', lambda: {
+        'getBusiness': GraphQLField(Business,
+            args={
+                'id': GraphQLArgument(GraphQLNonNull(GraphQLID)),
+            },
+            resolver=lambda root, args, context, info: context.business_data_loader.load(args.get('id'))
+        ),
+    })
+
+    schema = GraphQLSchema(query=Query)
+
+
+    doc = '''
+{
+    business1: getBusiness(id: "1") {
+        id
+    }
+    business2: getBusiness(id: "2") {
+        id
+    }
+}
+    '''
+    doc_ast = parse(doc)
+
+
+    load_calls = []
+    
+    class BusinessDataLoader(DataLoader):
+        def batch_load_fn(self, keys):
+            load_calls.append(keys)
+            return Promise.resolve(keys)
+
+    class Context(object):
+        business_data_loader = BusinessDataLoader()
+
+
+    result = execute(schema, doc_ast, None, context_value=Context())
+    assert not result.errors
+    assert result.data == {
+        'business1': {
+            'id': '1'
+        },
+        'business2': {
+            'id': '2'
+        },
+    }
+    assert load_calls == [['1','2']]
+
+
+def test_batches_multiple_together():
+
+    Location = GraphQLObjectType('Location', lambda: {
+        'id': GraphQLField(GraphQLID, resolver=lambda root, args, context, info: root),
+    })
+
+    Business = GraphQLObjectType('Business', lambda: {
+        'id': GraphQLField(GraphQLID, resolver=lambda root, args, context, info: root),
+        'location': GraphQLField(Location,
+            resolver=lambda root, args, context, info: context.location_data_loader.load('location-{}'.format(root))
+        ),
+    })
+
+    Query = GraphQLObjectType('Query', lambda: {
+        'getBusiness': GraphQLField(Business,
+            args={
+                'id': GraphQLArgument(GraphQLNonNull(GraphQLID)),
+            },
+            resolver=lambda root, args, context, info: context.business_data_loader.load(args.get('id'))
+        ),
+    })
+
+    schema = GraphQLSchema(query=Query)
+
+
+    doc = '''
+{
+    business1: getBusiness(id: "1") {
+        id
+        location {
+            id
+        }
+    }
+    business2: getBusiness(id: "2") {
+        id
+        location {
+            id
+        }
+    }
+}
+    '''
+    doc_ast = parse(doc)
+
+
+    business_load_calls = []
+    
+    class BusinessDataLoader(DataLoader):
+        def batch_load_fn(self, keys):
+            business_load_calls.append(keys)
+            return Promise.resolve(keys)
+
+    location_load_calls = []
+    
+    class LocationDataLoader(DataLoader):
+        def batch_load_fn(self, keys):
+            location_load_calls.append(keys)
+            return Promise.resolve(keys)
+
+    class Context(object):
+        business_data_loader = BusinessDataLoader()
+        location_data_loader = LocationDataLoader()
+
+
+    result = execute(schema, doc_ast, None, context_value=Context())
+    assert not result.errors
+    assert result.data == {
+        'business1': {
+            'id': '1',
+            'location': {
+                'id': 'location-1'
+            }
+        },
+        'business2': {
+            'id': '2',
+            'location': {
+                'id': 'location-2'
+            }
+        },
+    }
+    assert business_load_calls == [['1','2']]
+    assert location_load_calls == [['location-1','location-2']]