apollo server test client with support for context

apollo-test-client.ts

import { createTestClient } from "apollo-server-testing";
import { ApolloServer } from "apollo-server";
import {
  createResolvers,
  typeDefs,
  createContext,
  Context,
  CreateContextOptions,
} from "./server";
import { DocumentNode } from "graphql";

type StringOrAst = string | DocumentNode;

interface Query {
  query: StringOrAst;
  mutation?: undefined;
  variables?: {
    [name: string]: any;
  };
  operationName?: string;
  context?: Context;
}

interface Mutation {
  mutation: StringOrAst;
  query?: undefined;
  variables?: {
    [name: string]: any;
  };
  operationName?: string;
  context?: Context;
}

interface CreateApolloTestClientOptions {
  createContextOptions: CreateContextOptions;
}

export const createApolloTestClient = (
  options: CreateApolloTestClientOptions
) => {
  const defaultContext: Context = {
    req: {
      headers: {},
    },
  };
  let currentContext = defaultContext;

  const server = new ApolloServer({
    typeDefs,
    resolvers: createResolvers(),
    context: () => {
      return createContext(options.createContextOptions)(currentContext);
    },
  });

  const apolloTestClient = createTestClient(server);

  return {
    query: ({ context, ...query }: Query) => {
      currentContext = context ?? defaultContext;

      return apolloTestClient.query(query);
    },
    mutate: ({ context, ...mutate }: Mutation) => {
      currentContext = context ?? defaultContext;

      return apolloTestClient.mutate(mutate);
    },
  };
};