fix(Decimal): parse integers and floats as decimal. Also enable py38 in tox

graphene/types/decimal.py

@@ -2,7 +2,7 @@ from __future__ import absolute_import
 
 from decimal import Decimal as _Decimal
 
-from graphql.language.ast import StringValueNode
+from graphql.language.ast import StringValueNode, IntValueNode, FloatValueNode
 
 from .scalars import Scalar
 
@@ -23,7 +23,7 @@ class Decimal(Scalar):
 
     @classmethod
     def parse_literal(cls, node):
-        if isinstance(node, StringValueNode):
+        if isinstance(node, (StringValueNode, IntValueNode, FloatValueNode)):
             return cls.parse_value(node.value)
 
     @staticmethod

graphene/types/tests/test_decimal.py

@@ -41,3 +41,11 @@ def test_bad_decimal_query():
     result = schema.execute("""{ decimal(input: "%s") }""" % not_a_decimal)
     assert len(result.errors) == 1
     assert result.data is None
+
+
+def test_decimal_string_query_integer():
+    decimal_value = 1
+    result = schema.execute("""{ decimal(input: %s) }""" % decimal_value)
+    assert not result.errors
+    assert result.data == {"decimal": str(decimal_value)}
+    assert decimal.Decimal(result.data["decimal"]) == decimal_value

tox.ini

@@ -8,7 +8,7 @@ deps =
 setenv =
      PYTHONPATH = .:{envdir}
 commands =
-    py{36,37}: pytest --cov=graphene graphene examples {posargs}
+    py{36,37,38}: pytest --cov=graphene graphene examples {posargs}
 
 [testenv:pre-commit]
 basepython=python3.7