test: check projection with addRelation method

closes #370

src/__tests__/github_issues/370-test.ts

@@ -0,0 +1,89 @@
+import { SchemaComposer, graphql } from 'graphql-compose';
+import { composeMongoose } from '../../index';
+import { mongoose } from '../../__mocks__/mongooseCommon';
+import { Schema } from 'mongoose';
+
+const schemaComposer = new SchemaComposer<{ req: any }>();
+
+// mongoose.set('debug', true);
+
+const UserSchema = new mongoose.Schema({
+  firstName: {
+    type: String,
+    required: true,
+  },
+  _organizationIds: [
+    {
+      type: Schema.Types.ObjectId,
+      ref: 'Organization',
+      index: true,
+    },
+  ],
+});
+const UserModel = mongoose.model('User', UserSchema);
+const UserTC = composeMongoose(UserModel, { schemaComposer });
+
+const OrganizationSchema = new mongoose.Schema({
+  title: {
+    type: String,
+    required: true,
+  },
+});
+const OrganizationModel = mongoose.model('Organization', OrganizationSchema);
+const OrganizationTC = composeMongoose(OrganizationModel, { schemaComposer });
+
+UserTC.addRelation('organizations', {
+  resolver: () => OrganizationTC.mongooseResolvers.findByIds(),
+  prepareArgs: {
+    _ids: (source: any) => source._organizationIds,
+    skip: null,
+    sort: null,
+  },
+  projection: { _organizationIds: 1 },
+});
+
+schemaComposer.Query.addFields({
+  users: UserTC.mongooseResolvers.findMany(),
+});
+
+const schema = schemaComposer.buildSchema();
+
+beforeAll(async () => {
+  await OrganizationModel.base.createConnection();
+  const orgs = await OrganizationModel.create([
+    { title: 'Org1' },
+    { title: 'Org2' },
+    { title: 'Org3' },
+  ]);
+  await UserModel.create([
+    { firstName: 'User1', _organizationIds: [orgs[0]._id, orgs[1]._id] },
+    { firstName: 'User2', _organizationIds: [orgs[2]._id] },
+  ]);
+});
+afterAll(() => {
+  OrganizationModel.base.disconnect();
+});
+
+describe('issue #370 - addRelation: projection not working as expected ', () => {
+  it('check', async () => {
+    const result = await graphql.graphql({
+      schema,
+      source: `query {
+          users {
+            firstName
+            organizations {
+              title
+            }
+          }
+        }`,
+    });
+    expect(result).toEqual({
+      data: {
+        users: [
+          { firstName: 'User1', organizations: [{ title: 'Org1' }, { title: 'Org2' }] },
+          { firstName: 'User2', organizations: [{ title: 'Org3' }] },
+        ],
+      },
+    });
+  });
+});