coerce_string should return a unicode string always.

* For some reason, once string coercion was changed to unicode, I noticed some stuff in Schema going awry. This led me to realize that types in a Schema weren't being ordered. They should be though, so I changed the schema.type_map() to return an OrderedDict. This removed the need for `sort_lists` in the schema tests. So I got rid of those too.

Closes #21

Author: jhgg

graphql/core/type/scalars.py

@@ -1,3 +1,4 @@
+from six import text_type
 from ..language.ast import (
     BooleanValue,
     FloatValue,
@@ -61,13 +62,15 @@ def parse_float_literal(ast):
 
 def coerce_string(value):
     if isinstance(value, bool):
-        return 'true' if value else 'false'
-    return str(value)
+        return u'true' if value else u'false'
+
+    return text_type(value)
 
 
 def parse_string_literal(ast):
     if isinstance(ast, StringValue):
         return ast.value
+
     return None
 
 GraphQLString = GraphQLScalarType(name='String',

graphql/core/type/schema.py

@@ -1,3 +1,4 @@
+from collections import OrderedDict
 from .definition import (
     GraphQLInputObjectType,
     GraphQLInterfaceType,
@@ -70,7 +71,7 @@ def get_directive(self, name):
         return None
 
     def _build_type_map(self):
-        type_map = {}
+        type_map = OrderedDict()
         for type in (self.get_query_type(), self.get_mutation_type(), IntrospectionSchema):
             type_map = type_map_reducer(type_map, type)
 

tests/core_execution/test_variables.py

@@ -612,4 +612,4 @@ def test_when_argument_provided_cannot_be_parsed(self):
             'data': {
                 'fieldWithDefaultArgumentValue': '"Hello World"'
             }
-        })
+        })