Lambda SES bounce event handler unit test

index.test.js

'use strict';

const AWS = require('aws-sdk-mock');
const assert = require('assert');
const testFn = require('lambda-tester');
const receiver = require('../index').handler;

const complaintNotification = require('./resources/complaintNotification.json');
const missingHeaders = require('./resources/missingHeaders.json');
const missingTargetArn = require('./resources/missingTargetArnHeader.json');
const bounceNotification = require('./resources/bounceNotification.json');

process.env.DLQ_URL = 'http://localhost';

describe('Testing Lambda handler', async (done) => {
  describe('Test non-Bounce message', function () {
    it('Should return 200 and return not a bounce message', async function () {
      AWS.mock('SQS', 'sendMessage', (params) => {
        assert.strictEqual(params.MessageBody, JSON.stringify(complaintNotification));
        assert.strictEqual(params.QueueUrl, 'http://localhost');
        return Promise.resolve('Success');
      });

      let params = {
        Records: [{
          Sns: {
            Message: JSON.stringify(complaintNotification)
          }
        }]
      };

      await testFn(receiver)
      .event(params)
      .expectResolve((result) => {
        assert.strictEqual(result.statusCode, 200);
        assert.strictEqual(result.body, '{"message":"Not a bounce message"}');
      });

      AWS.restore('SQS', 'sendMessage');
    });

    it('Should return 200, with original headers missing message', async function () {
      AWS.mock('SQS', 'sendMessage', (params) => {
        assert.strictEqual(params.MessageBody, JSON.stringify(missingHeaders));
        assert.strictEqual(params.QueueUrl, 'http://localhost');
        return Promise.resolve('Success');
      });

      let params = {
        Records: [{
          Sns: {
            Message: JSON.stringify(missingHeaders)
          }
        }]
      };

      await testFn(receiver)
      .event(params)
      .expectResolve((result) => {
        assert.strictEqual(result.statusCode, 200);
        assert.strictEqual(result.body, '{"message":"Original message headers missing"}');
      });

      AWS.restore('SQS', 'sendMessage');
    });

    it('Should return 200, with TargetArn header message missing', async function () {
      AWS.mock('SQS', 'sendMessage', (params) => {
        assert.strictEqual(params.MessageBody, JSON.stringify(missingTargetArn));
        assert.strictEqual(params.QueueUrl, 'http://localhost');
        return Promise.resolve('Success');
      });

      let params = {
        Records: [{
          Sns: {
            Message: JSON.stringify(missingTargetArn)
          }
        }]
      };

      await testFn(receiver)
      .event(params)
      .expectResolve((result) => {
        assert.strictEqual(result.statusCode, 200);
        assert.strictEqual(result.body, '{"message":"Missing TargetArn header"}');
      });

      AWS.restore('SQS', 'sendMessage');
    });
  });

  describe('Test successful message delivery', function () {
    it('Should return 200, with successful SNS call', async function () {
      AWS.mock('SNS', 'publish', (params) => {
        assert.strictEqual(params.Message, '{"messageId":"00000138111222aa-33322211-cccc-cccc-cccc-ddddaaaa0680-000000","bounceType":"Permanent","bounceSubType":"General","timestamp":"2016-01-27T14:59:38.237Z","bouncedRecipients":[{"emailAddress":"jane@example.com"}]}');
        assert.strictEqual(params.Subject, 'Here is a bounced email notification')
        assert.strictEqual(params.TargetArn, 'arn:sns:batman:is:bruce:wayne');
        return Promise.resolve('Success');
      });

      let params = {
        Records: [{
          Sns: {
            Message: JSON.stringify(bounceNotification)
          }
        }]
      };

      await testFn(receiver)
      .event(params)
      .expectResolve((result) => {
        assert.strictEqual(result.statusCode, 200);
        assert.strictEqual(result.body, '{"message":"ok"}');
      });

      AWS.restore('SNS', 'publish');
    });
  });

  done();
});