test: add example for beforeQuery param

Related #219

src/__tests__/github_issues/219-test.js

@@ -0,0 +1,99 @@
+/* eslint-disable no-param-reassign */
+/* @flow */
+
+import { schemaComposer, graphql } from 'graphql-compose';
+import { composeWithMongoose } from '../../index';
+import { UserModel } from '../../__mocks__/userModel';
+
+beforeAll(async () => {
+  await UserModel.base.connect();
+  await UserModel.create({
+    name: 'AAAAA',
+    age: 10,
+  });
+  await UserModel.create({
+    name: 'BBBBB',
+    age: 20,
+  });
+});
+afterAll(() => UserModel.base.disconnect());
+
+const UserTC = composeWithMongoose(UserModel);
+
+describe('issue #219 - Authorization using wrapResolve', () => {
+  it('correct request', async () => {
+    UserTC.wrapResolverResolve('findOne', (next) => (rp) => {
+      rp.beforeQuery = async (query) => {
+        // Choose any case or mix of them
+        // 1) check rp.context
+        // 2) make another query await Permission.find();
+        // 3) modify query = query.where({ perm: 'ALLOWED', userId: context?.req?.user?.id })
+        query = query.where({ age: { $gt: 19 } });
+
+        // 4) return cached data return UserCachedData[rp.args.id];
+        if (rp?.args?.filter?.name === 'CACHED') {
+          return { name: 'CACHED', age: 99 };
+        }
+
+        // 5) just check arg value
+        if (rp?.args?.filter?.name === 'ERROR') {
+          throw new Error('Wrong arg!');
+        }
+
+        return query.exec();
+      };
+      return next(rp);
+    });
+    schemaComposer.Query.addFields({
+      findUser: UserTC.getResolver('findOne'),
+    });
+    const schema = schemaComposer.buildSchema();
+    expect(
+      await graphql.graphql(
+        schema,
+        `query {
+          findUser(filter: { name: "AAAAA" }) {
+            name
+            age
+          }
+        }`
+      )
+    ).toEqual({ data: { findUser: null } });
+
+    expect(
+      await graphql.graphql(
+        schema,
+        `query {
+          findUser(filter: { name: "BBBBB" }) {
+            name
+            age
+          }
+        }`
+      )
+    ).toEqual({ data: { findUser: { age: 20, name: 'BBBBB' } } });
+
+    expect(
+      await graphql.graphql(
+        schema,
+        `query {
+          findUser(filter: { name: "CACHED" }) {
+            name
+            age
+          }
+        }`
+      )
+    ).toEqual({ data: { findUser: { age: 99, name: 'CACHED' } } });
+
+    expect(
+      await graphql.graphql(
+        schema,
+        `query {
+          findUser(filter: { name: "ERROR" }) {
+            name
+            age
+          }
+        }`
+      )
+    ).toEqual({ data: { findUser: null }, errors: [new Error('Wrong arg!')] });
+  });
+});