message: Missing providers list on module gives error
diff: @@ -11,6 +11,66 @@ import {
  import { makeExecutableSchema } from '@graphql-tools/schema';
  import { parse, execute } from 'graphql';
  +test('No error in case of module without providers', async () => {
  + @Injectable({
  + scope: Scope.Operation,
  + })
  + class Data {
  + lorem() {
  + return 'ipsum';
  + }
  + }
  +
  + const mod = createModule({
  + id: 'lorem',
  + typeDefs: gql`
  + type Query {
  + lorem: String
  + }
  + `,
  + resolvers: {
  + Query: {
  + lorem(
  + _parent: {},
  + _args: {},
  + { injector }: GraphQLModules.ModuleContext
  + ) {
  + return injector.get(Data).lorem();
  + },
  + },
  + },
  + });
  +
  + const app = createApplication({
  + modules: [mod],
  + providers: [Data],
  + });
  +
  + const schema = makeExecutableSchema({
  + typeDefs: app.typeDefs,
  + resolvers: app.resolvers,
  + });
  +
  + const contextValue = { request: {}, response: {} };
  + const document = parse(/* GraphQL */ `
  + {
  + lorem
  + }
  + `);
  +
  + const result = await app.createExecution()({
  + schema,
  + contextValue,
  + document,
  + });
  +
  + // Should resolve data correctly
  + expect(result.errors).toBeUndefined();
  + expect(result.data).toEqual({
  + lorem: 'ipsum',
  + });
  +});
  +
  test('Operation scoped provider should be created once per GraphQL Operation', async () => {
  const constructorSpy = jest.fn();
  const loadSpy = jest.fn();
  