How to write tests for typeorm + typegraphql + typescript?

Good day.

I wrote a small application using typeorm + typegraphql + typescript. It works and everything seems to be fine.

the essence of the problem is that it is not possible to understand the invention for testing ... I understand that you need to connect to the database and run a couple of mutations, and basically everything ...

The documentation could not find the correct connections to resolvers

import {
  Resolver,
  Mutation,
  Arg,
  Int,
  Query,
} from "type-graphql";
import { Author } from "../entity/Author";
import { AuthorBook } from "../entity/AuthorBook";
import { Book } from "../entity/Book";
@Resolver()
export class AuthorBookResolver {
  @Mutation(() => Book)
  async createBook(
    @Arg("name") name: string,
    @Arg("pageCount") pageCount: number,
  ) {
    return Book.create({ name, pageCount }).save();
  }

  @Mutation(() => Author)
  async createAuthor(@Arg("name") name: string) {
    return Author.create({ name }).save();
  }

  @Mutation(() => Boolean)
  async addAuthorBook(
    @Arg("authorId", () => Int) authorId: number,
    @Arg("bookId", () => Int) bookId: number
  ) {
    await AuthorBook.create({ authorId, bookId }).save();
    return true;
  }

  @Mutation(() => Boolean)
  async deleteBook(@Arg("bookId", () => Int) bookId: number) {
    await AuthorBook.delete({ bookId });
    await Book.delete({ bookId });
    return true;
  }

  @Query(() => [Book])
  async books() {
    return Book.find();
  }
}