add more test cases for unions implementing interfaces

Author: yaacovCR

src/execution/__tests__/union-interface-test.ts

@@ -110,6 +110,7 @@ const CatType: GraphQLObjectType = new GraphQLObjectType({
 
 const PetType = new GraphQLUnionType({
   name: 'Pet',
+  interfaces: [MammalType, LifeType, NamedType],
   types: [DogType, CatType],
   resolveType(value) {
     if (value instanceof Dog) {
@@ -212,7 +213,7 @@ describe('Execute: Union and intersection types', () => {
           kind: 'UNION',
           name: 'Pet',
           fields: null,
-          interfaces: [],
+          interfaces: [{ name: 'Mammal' }, { name: 'Life' }, { name: 'Named' }],
           possibleTypes: [{ name: 'Dog' }, { name: 'Cat' }],
           enumValues: null,
           inputFields: null,
@@ -264,12 +265,11 @@ describe('Execute: Union and intersection types', () => {
         name
         pets {
           __typename
+          name
           ... on Dog {
-            name
             barks
           }
           ... on Cat {
-            name
             meows
           }
         }
@@ -436,12 +436,11 @@ describe('Execute: Union and intersection types', () => {
 
       fragment PetFields on Pet {
         __typename
+        name
         ... on Dog {
-          name
           barks
         }
         ... on Cat {
-          name
           meows
         }
       }

src/validation/__tests__/PossibleFragmentSpreadsRule-test.ts

@@ -121,6 +121,13 @@ describe('Validate: Possible fragment spreads', () => {
     `);
   });
 
+  it('interface into implemented union', () => {
+    expectValid(`
+      fragment interfaceWithinUnion on DogOrCat { ...petFragment }
+      fragment petFragment on Pet { name }
+    `);
+  });
+
   it('interface into overlapping interface', () => {
     expectValid(`
       fragment interfaceWithinInterface on Pet { ...beingFragment }