Add test for nested projection

Not uet failing but I have set mongoose debug to true which will show the find query being run during the test.
This shows that the entire Author subdocument is being fetching.

Author: natac13

src/__tests__/github_issues/271-test.ts

@@ -0,0 +1,86 @@
+import { SchemaComposer, graphql } from 'graphql-compose';
+import { composeMongoose } from '../../index';
+import { mongoose } from '../../__mocks__/mongooseCommon';
+import { Document } from 'mongoose';
+import { convertSchemaToGraphQL } from '../../../src/fieldsConverter';
+const schemaComposer = new SchemaComposer<{ req: any }>();
+
+const AuthorSchema = new mongoose.Schema(
+  {
+    name: { type: String },
+    age: { type: Number },
+    isAlive: { type: Boolean },
+  },
+  { _id: false }
+);
+
+const BookSchema = new mongoose.Schema({
+  _id: { type: Number },
+  title: { type: String, required: true },
+  pageCount: { type: Number },
+  author: { type: AuthorSchema },
+});
+
+interface IAuthor {
+  name: string;
+  age: number;
+  isAlive: boolean;
+}
+
+interface IBook extends Document {
+  _id: number;
+  title: string;
+  author: IAuthor;
+  pageCount?: number;
+}
+
+const BookModel = mongoose.model<IBook>('Book', BookSchema);
+
+convertSchemaToGraphQL(AuthorSchema, 'Author', schemaComposer);
+
+const BookTC = composeMongoose(BookModel, { schemaComposer });
+
+schemaComposer.Query.addFields({
+  bookById: BookTC.mongooseResolvers.findById(),
+  bookFindOne: BookTC.mongooseResolvers.findOne(),
+  booksMany: BookTC.mongooseResolvers.findMany(),
+});
+
+const schema = schemaComposer.buildSchema();
+
+beforeAll(async () => {
+  mongoose.set('debug', true);
+  await BookModel.base.createConnection();
+  await BookModel.create({
+    _id: 1,
+    title: 'Atlas Shrugged',
+    author: { age: new Date().getFullYear() - 1905, isAlive: false, name: 'Ayn Rand' },
+    pageCount: 1168,
+  });
+});
+afterAll(() => {
+  mongoose.set('debug', false);
+  BookModel.base.disconnect();
+});
+
+describe('nested projection - issue #271', () => {
+  it('Happy Path', async () => {
+    const result = await graphql.graphql({
+      schema,
+      source: `query {
+          booksMany {
+            title
+            pageCount
+            author { name }
+          }
+        }`,
+      contextValue: {},
+    });
+    console.log(JSON.stringify(result));
+    // expect(BookModel.find).toHaveBeenCalledTimes(1);
+    // expect(BookModel.find).toHaveBeenCalledWith(
+    //   {},
+    //   { limit: 1000, projection: { title: true, pageCount: true, 'author.name': true } }
+    // );
+  });
+});