tests: query for nested interface

__tests__/gql/queries/object-kitchen-sink.gql

@@ -66,6 +66,15 @@ query TestObject($id: ID!) {
         label
       }
     }
+    interfaceNestedNonNullField {
+      ... on TestInterface {
+        id
+        label
+      }
+      ... on TestImplOne {
+        description
+      }
+    }
     relayConnectionField(first: 1, after: "VGVzdFJlbGF5Tm9kZTox") {
       ...testRelayConnection
     }

__tests__/gql/schema.gql

@@ -29,6 +29,7 @@ type Query {
   testInterface(id: ID, label: String): TestInterface
   testInterfaceNonNull(id: ID, label: String): TestInterface!
   testInterfaceOptional(id: ID!): TestInterface
+  testInterfaceMultiple(id: ID, label: String): [TestInterface]
   testObject(id: ID!): TestObject
   testObjectNonNull(id: ID!): TestObject!
   testObjects(size: String): [TestObject]
@@ -91,6 +92,7 @@ type TestObject {
   hasManyNestedNonNullField: [TestOption!]!
   interfaceField: TestInterface
   interfaceNonNullField: TestInterface!
+  interfaceNestedNonNullField: [TestInterface!]!
   relayConnectionField(first: Int, after: String): TestRelayConnection
   relayConnectionFilteredField(
     first: Int

__tests__/integration/queries/object-kitchen-sink-test.js

@@ -28,6 +28,13 @@ describe("Integration | queries | object", function () {
       server.create("test-union-one", { oneName: "foo" }),
       server.create("test-union-two", { twoName: "bar" }),
     ];
+    const testInterfaces = [
+      server.create("test-impl-one", {
+        description: "description",
+        label: "impl",
+      }),
+      server.create("test-impl-two", { label: "impl" }),
+    ];
 
     seedUnassociatedRecords(server);
 
@@ -41,6 +48,7 @@ describe("Integration | queries | object", function () {
       hasManyNonNullField: testOptions,
       hasManyNestedNonNullField: testOptions,
       interfaceField: testImpl,
+      interfaceNestedNonNullField: testInterfaces,
       interfaceNonNullField: testImpl,
       relayConnectionField: testRelayNodes,
       relayConnectionFilteredField: testRelayNodes,
@@ -66,6 +74,10 @@ describe("Integration | queries | object", function () {
       hasManyNonNullField: [{ id: "1", name: "opt" }],
       hasManyNestedNonNullField: [{ id: "1", name: "opt" }],
       interfaceField: { id: "1", label: "impl" },
+      interfaceNestedNonNullField: [
+        { id: "2", label: "impl", description: "description" },
+        { id: "1", label: "impl" },
+      ],
       interfaceNonNullField: { id: "1", label: "impl" },
       relayConnectionField: {
         edges: [{ cursor: "VGVzdFJlbGF5Tm9kZToy", node: { id: "2" } }],

__tests__/unit/resolvers/mirage-field-resolver-test.js

@@ -106,6 +106,23 @@ describe("Unit | resolvers | mirage field resolver", function () {
         args,
         context,
         info,
+        false,
+        type
+      );
+    });
+
+    it("can resolve interface list types", function () {
+      const type = typeMap.TestInterface;
+      const info = { returnType: queryFields.testInterfaceMultiple.type };
+
+      mirageGraphQLFieldResolver(obj, args, context, info);
+
+      expect(resolveInterface).toHaveBeenCalledWith(
+        obj,
+        args,
+        context,
+        info,
+        true,
         type
       );
     });

lib/resolvers/interface.js

@@ -1,3 +1,4 @@
+import resolveList from "./list";
 import resolveObject from "./object";
 
 function getTypeFromInlineFragment(info) {
@@ -39,15 +40,25 @@ function resolveFromImplementations(obj, args, context, info, type) {
  * @param {Object} args
  * @param {Object} context
  * @param {Object} info
+ * @param {Boolean} isList
  * @param {Object} type An unwrapped type.
  * @see {@link https://graphql.org/learn/execution/#root-fields-resolvers}
  * @see resolveObject
  * @returns {Object} A record from Mirage's database.
  */
-export default function resolveInterface(obj, args, context, info, type) {
+export default function resolveInterface(
+  obj,
+  args,
+  context,
+  info,
+  isList,
+  type
+) {
   const implType = getTypeFromInlineFragment(info);
 
-  return implType
+  return isList
+    ? resolveList(obj, args, context, info, type)
+    : implType
     ? resolveObject(obj, args, context, info, implType)
     : resolveFromImplementations(obj, args, context, info, type);
 }

lib/resolvers/mirage.js

@@ -30,7 +30,7 @@ export default function mirageGraphQLFieldResolver(obj, args, context, info) {
   let { isList, type } = unwrapType(info.returnType);
 
   return isInterfaceType(type)
-    ? resolveInterface(obj, args, context, info, type)
+    ? resolveInterface(obj, args, context, info, isList, type)
     : isUnionType(type)
     ? resolveUnion(obj, args, context, info, isList, type)
     : !isObjectType(type)