Testing AWS AppSync Resolver Error functions

Question

I have been following https://docs.aws.amazon.com/appsync/latest/devguide/test-debug-resolvers-js.html to write unit tests for my AppSync functions and resolvers. Everything works well until I try to test the error states. My code is as follows:

code.js

import { util } from '@aws-appsync/utils'

/**
 * Request a single item with `id` from the attached DynamoDB table datasource
 * @param ctx the context object holds contextual information about the function invocation.
 */
export function request(ctx) {
  const { args: { id } } = ctx
  return { 
    operation: 'GetItem',
    key: util.dynamodb.toMapValues({ id })
  }
}

/**
 * Returns the result directly
 * @param ctx the context object holds contextual information about the function invocation.
 */
export function response(ctx) {
  const { error, result } = ctx;
  if (error) {
    return util.appendError(error.message, error.type, result);
  }
  return result;
}

context.json

{
  "arguments": {
    "id": "1234",
    "description": "test"
  },
  "source": {},
  "result": {
    "id": "1234"
  },
  "request": {},
  "error": {
    "type": "ERROR",
    "message": "Error Happened"
  },
  "prev": {}
}

code.test.js

const AWS = require('aws-sdk')
const fs = require('fs')
const client = new AWS.AppSync({ region: 'us-east-2' })
const runtime = {name:'APPSYNC_JS',runtimeVersion:'1.0.0')

test('Error handling', async () => {
  const code = fs.readFileSync('./code.js', 'utf8')
  const context = fs.readFileSync('./context.json', 'utf8')
  const contextJSON = JSON.parse(context)
  
  const response = await client.evaluateCode({ code, context, runtime, function: 'request' }).promise()
  const result = JSON.parse(response.evaluationResult)

  expect(result).not.toEqual("")
})

I'm expecting the response to come back with the result and errors block but instead get an empty string as the "evaluated response function", I think this is due to appendError returning void but I'm not entirely sure how to fix it so it returns the result and error blocks.

Testing AWS AppSync Resolver Error functions

0 Answers0