How to use Jest to test file download? - unit-testing

I have some code as below:
/* global document */
/* global window */
/* global Blob */
import FileSaver from 'file-saver';
export const createDownloadFromBlob = (blob, filename, extension) => {
FileSaver.saveAs(blob, `${filename}.${extension}`);
};
export const createDownload = (content, filename, extension) => {
createDownloadFromBlob(new Blob([content], { type: 'application/octet-stream' }), filename, extension);
};
I want to use Jest to unit-test these two methods, but I don't know where to start. Any help would be appreciated.

I would mock out FileSaver with a spy:
import FileSaver from 'file-saver';
jest.mock('file-saver', ()=>({saveAs: jest.fn()}))
As you cant compare Blobs I would mock this as well:
global.Blob = function (content, options){return ({content, options})}
now you can run your test and use expect like this
createDownload('content', 'filename', 'extension')
expect(FileSaver.saveAs).toHaveBeenCalledWith(
{content:'content', options: { type: 'application/octet-stream' }},
'filename.extension'
)

In Typescript: If you create a Blob with a ArrayBuffer or binary data then you need handle that case separately than strings.
import * as CRC32 from 'crc-32';
(window as any).global.Blob = function(content, options) {
// for xlxs blob testing just return the CRC of the ArrayBuffer
// and not the actual content of it.
if (typeof content[0] !== 'string') {
content = CRC32.buf(content);
}
return {content: JSON.stringify(content), options};
};

Related

Trouble Writing to Jest Mocked Prisma Database

I have two databases that I need to interact with in my code. I have a simple function that takes an object and writes it to my PostgreSQL database using Prisma. I've tested the function with Postman, and it works perfectly, but when I try to execute it using a Jest mock (using the singleton pattern found in the Prisma unit testing guide), it returns undefined indicating that it didn't interact with the database and create the new record. Here's my code:
/prisma/clinical-schema.prisma
generator client {
provider = "prisma-client-js"
output = "./generated/clinical"
}
datasource clinicalDatabase {
provider = "postgresql"
url = "postgresql://postgres:postgres#localhost:5432/clinical-data?schema=public"
}
model pcc_webhook_update {
id Int #id #default(autoincrement())
event_type String
organization_id Int
facility_id Int
patient_id Int
resource_id String?
webhook_date DateTime #default(now()) #clinicalDatabase.Timestamptz(6)
status pcc_webhook_update_status #default(pending)
status_changed_date DateTime? #clinicalDatabase.Timestamptz(6)
error_count Int #default(0)
##unique([organization_id, facility_id, patient_id, resource_id, event_type, status])
}
enum pcc_webhook_update_status {
pending
processing
processed
error
}
/prisma/clinical-client.ts
import { PrismaClient } from './generated/clinical';
const prismaClinical = new PrismaClient();
export default prismaClinical;
/testing/prisma-clinical-mock.ts
import { PrismaClient } from '../prisma/generated/clinical';
import { mockDeep, mockReset, DeepMockProxy } from 'jest-mock-extended';
import prisma from '../prisma/clinical-client';
jest.mock('../prisma/clinical-client', () => ({
__esModule: true,
default: mockDeep<PrismaClient>()
}));
beforeEach(() => {
mockReset(prismaClinicalMock);
});
export const prismaClinicalMock = prisma as unknown as DeepMockProxy<PrismaClient>;
Everything up to this point follows the conventions outlined by the Prisma unit testing docs. The only modification I made was to make it database specific. Below is my function and tests. The request object in handle-pcc-webhooks.ts is a sample http request object, the body of which contains the webhook data I care about.
/functions/handle-pcc-webhooks/handler.ts
import prismaClinical from '../../../prisma/clinical-client';
import { pcc_webhook_update } from '../../../prisma/generated/clinical';
import { requestObject } from './handler.types';
export const handlePccWebhook = async (request: requestObject) => {
try {
const webhook = JSON.parse(request.body);
// if the webhook doesn't include a resource id array, set it to an array with an empty string to ensure processing and avoid violating
// the multi-column unique constraint on the table
const { resourceId: resourceIds = [''] } = webhook;
let records = [];
for (const resourceId of resourceIds) {
// update an existing record if one exists in the pending state, otherwise create a new entry
const record: pcc_webhook_update = await prismaClinical.pcc_webhook_update.upsert({
where: {
organization_id_facility_id_patient_id_resource_id_event_type_status: {
organization_id: webhook.orgId,
facility_id: webhook.facId,
patient_id: webhook.patientId,
resource_id: resourceId,
event_type: webhook.eventType,
status: 'pending'
}
},
update: {
webhook_date: new Date()
},
create: {
event_type: webhook.eventType,
organization_id: webhook.orgId,
facility_id: webhook.facId,
patient_id: webhook.patientId,
resource_id: resourceId,
status: 'pending' // not needed
}
});
records.push(record);
}
return records;
} catch (error) {
console.error(error);
}
};
/functions/handle-pcc-webhooks/handler.spec.ts
import fs from 'fs';
import path from 'path';
import MockDate from 'mockdate';
import { prismaClinicalMock } from '../../../testing/prisma-clinical-mock';
import { createAllergyAddRecord } from './__mocks__/allergy';
import { requestObject } from './handler.types';
import { handlePccWebhook } from './handler';
describe('allergy.add', () => {
let requestObject: requestObject;
let allergyAddRecord: any;
beforeAll(() => {
requestObject = getRequestObject('allergy.add');
});
beforeEach(() => {
MockDate.set(new Date('1/1/2022'));
allergyAddRecord = createAllergyAddRecord(new Date());
});
afterEach(() => {
MockDate.reset();
});
test('should create an allergy.add database entry', async() => {
prismaClinicalMock.pcc_webhook_update.create.mockResolvedValue(allergyAddRecord);
// this is where I would expect handlePccWebhook to return the newly created database
// record, but instead it returns undefined. If I run the function outside of this
// unit test, with the same input value, it functions perfectly
await expect(handlePccWebhook(requestObject)).resolves.toEqual([allergyAddRecord]);
});
});
// This just builds a request object with the current webhook being tested
function getRequestObject(webhookType: string) {
// read the contents of request object file as a buffer, then convert it to JSON
const rawRequestObject = fs.readFileSync(path.resolve(__dirname, '../../sample-data/handle-pcc-webhook-request.json'));
const requestObject: requestObject = JSON.parse(rawRequestObject.toString());
// read the contents of the webhook file as a buffer, then convert it to a string
const rawWebhook = fs.readFileSync(path.resolve(__dirname, `../../sample-data/${webhookType}.json`));
const webhookString = rawWebhook.toString();
// set the body of the request object to the contents of the target webhook
requestObject.body = webhookString;
return requestObject;
}
Finally, here is the result of running the unit test:
So after banging my had against the wall for a few hours, I figured out the issue. In my handler.spec.ts file, I had the following line:
prismaClinicalMock.pcc_webhook_update.create.mockResolvedValue(allergyAddRecord);
what that does is mock the value returned for any create functions run using Prisma. The issue is that my function is using an upsert function, which I wasn't explicitly mocking, thus returning undefined. I changed the above line to
prismaClinicalMock.pcc_webhook_update.upsert.mockResolvedValue(allergyAddRecord);
and it started working.

is there a way to get string (data) from text file stored in s3 in Alexa localisation.js file?

Problem:
I am trying to get the data from a text file stored in s3, I get it right in intent handler using a sync await but I want to get string in localisation file as I am trying to implement the solution in 2 languages.
I am getting err saying skill does not respond correctly.
This is file.js
const AWS = require('aws-sdk');
//========================
// This step is not required if you are running your code inside lambda or in
// the local environment that has AWS set up
//========================
const s3 = new AWS.S3();
async function getS3Object (bucket, objectKey) {
try {
const params = {
Bucket: 'my-bucket',
Key: 'file.txt',
};
const data = await s3.getObject(params).promise();
let dat = data.Body.toString('utf-8');
return dat;
} catch (e) {
throw new Error(`Could not retrieve file from S3: ${e.message}`);
}
}
module.exports = getS3Object;
this is the localisation.js file code
const dataText = require('file.js');
async let textTitle = await dataText().then(); **// this does not work**
module.exports = {
en: {
translation: {
WELCOME_BACK_MSG : textTitle,
}
},
it: {
translation: {
WELCOME_MSG: textTitle,
}
}
}
The problem is that in your localisation.js file you are trying to export something that is obtained via an asynchronous function call, but you cannot do that directly, module.exports is assigned and returned synchronously. Please, see for instance this SO question and answer for an in-deep background.
As you are mentioning Alexa skill, and for the name of the file, localisation.js, I assume you are trying something similar to the solution proposed in this GitHub repository.
Analyzing the content of the index.js file they provide, it seems the library is using i18next for localisation.
The library provides the concept of backend if you need to load your localisation information from an external resource.
You can implement a custom backend, although the library offers one that could fit your needs, i18next-http-backend.
As indicated in the documentation, you can configure the library to fetch your localization resources with this backend with something like the following:
import i18next from 'i18next';
import Backend from 'i18next-http-backend';
i18next
.use(Backend)
.init({
backend: {
// for all available options read the backend's repository readme file
loadPath: '/locales/{{lng}}/{{ns}}.json'
}
});
Here in SO you can find a more complete example.
You need to provide a similar configuration to the localisation interceptor provided in the Alexa skill example project, perhaps something like:
import HttpApi from 'i18next-http-backend';
/**
* This request interceptor will bind a translation function 't' to the handlerInput
*/
const LocalizationInterceptor = {
process(handlerInput) {
const localisationClient = i18n
.use(HttpApi)
.init({
lng: Alexa.getLocale(handlerInput.requestEnvelope),
// resources: languageStrings,
backend: {
loadPath: 'https://your-bucket.amazonaws.com/locales/{{lng}}/translations.json',
crossDomain: true,
},
returnObjects: true
});
localisationClient.localise = function localise() {
const args = arguments;
const value = i18n.t(...args);
if (Array.isArray(value)) {
return value[Math.floor(Math.random() * value.length)];
}
return value;
};
handlerInput.t = function translate(...args) {
return localisationClient.localise(...args);
}
}
};
Please, be aware that instead of a text file you need to return a valid son file with the appropriate translations:
{
"WELCOME_MSG" : "Welcome!!",
"WELCOME_BACK_MSG" : "Welcome back!!"
}

Webpack 4 Plugin: Add module and get result from loader

I am making a Webpack 4 plugin for fun and to try to understand its internals. The idea is simple:
Parse an HTML template file into a tree;
Get the asset paths from <img src="..."> and <link href="...">;
Add the assets to dependencies to load them through the file-loader;
Get the path emitted from file-loader(which might include a hash)and fix the nodes in the tree;
Emit the final HTML string into a file.
So far, I am stuck at step 4. Parsing the template and extracting the asset paths was easy thanks to parse5, to load the assets, I used the PrefetchPlugin but now I don't know how to get the result from file-loader.
I need to load the result because it generates a hash and might change the location of the asset:
{
exclude: /\.(css|jsx?|mjs)$/,
use: [{
loader: 'file-loader',
options: {
name: '[name].[ext]?[sha512:hash:base64:8]`',
},
}],
}
Not only that, but I want to use the url-loader later which might generate the asset encoded. I am trying to get the result from the loader at tapAfterCompile.
The current source code for the plugin is as follows:
import debug from 'debug'
import prettyFormat from 'pretty-format'
import validateOptions from 'schema-utils'
import {dirname, resolve} from 'path'
import {html as beautifyHtml} from 'js-beautify'
import {minify as minifyHtml} from 'html-minifier'
import {parse, serialize} from 'parse5'
import {PrefetchPlugin} from 'webpack'
import {readFileSync} from 'fs'
let log = debug('bb:config:webpack:plugin:html')
const PLUGIN_NAME = 'HTML Plugin'
/**
* This schema is used to validate the plugin’s options, right now, all it does
* is requiring the template property.
*/
const OPTIONS_SCHEMA = {
additionalProperties: false,
type: 'object',
properties: {
minify: {
type: 'boolean',
},
template: {
type: 'string',
},
},
required: ['template'],
}
/**
* Extract an attribute’s value from the node; Returns undefined if the
* attribute is not found.
*/
function getAttributeValue(node, attributeName) {
for (let attribute of node.attrs) {
if (attribute.name === attributeName)
return attribute.value
}
return undefined
}
/**
* Update a node’s attribute value.
*/
function setAttributeValue(node, attributeName, value) {
for (let attribute of node.attrs) {
if (attribute.name === attributeName)
attribute.value = value
}
}
/**
* Recursively walks the parsed tree. It should work in 99.9% of the cases but
* it needs to be replaced with a non recursive version.
*/
function * walk(node) {
yield node
if (!node.childNodes)
return
for (let child of node.childNodes)
yield * walk(child)
}
/**
* Actual Webpack plugin that generates an HTML from a template, add the script
* bundles and and loads any local assets referenced in the code.
*/
export default class SpaHtml {
/**
* Options passed to the plugin.
*/
options = null
/**
* Parsed tree of the template.
*/
tree = null
constructor(options) {
this.options = options
validateOptions(OPTIONS_SCHEMA, this.options, PLUGIN_NAME)
}
/**
* Webpack will call this method to allow the plugin to hook to the
* compiler’s events.
*/
apply(compiler) {
let {hooks} = compiler
hooks.afterCompile.tapAsync(PLUGIN_NAME, this.tapAfterCompile.bind(this))
hooks.beforeRun.tapAsync(PLUGIN_NAME, this.tapBeforeRun.bind(this))
}
/**
* Return the extracted the asset paths from the tree.
*/
* extractAssetPaths() {
log('Extracting asset paths...')
const URL = /^(https?:)?\/\//
const TEMPLATE_DIR = dirname(this.options.template)
for (let node of walk(this.tree)) {
let {tagName} = node
if (!tagName)
continue
let assetPath
switch (tagName) {
case 'link':
assetPath = getAttributeValue(node, 'href')
break
case 'img':
assetPath = getAttributeValue(node, 'src')
break
}
// Ignore empty paths and URLs.
if (!assetPath || URL.test(assetPath))
continue
const RESULT = {
context: TEMPLATE_DIR,
path: assetPath,
}
log(`Asset found: ${prettyFormat(RESULT)}`)
yield RESULT
}
log('Done extracting assets.')
}
/**
* Returns the current tree as a beautified or minified HTML string.
*/
getHtmlString() {
let serialized = serialize(this.tree)
// We pass the serialized HTML through the minifier to remove any
// unnecessary whitespace that could affect the beautifier. When we are
// actually trying to minify, comments will be removed too. Options can be
// found in:
//
// https://github.com/kangax/html-minifier
//
const MINIFIER_OPTIONS = {
caseSensitive: false,
collapseBooleanAttributes: true,
collapseInlineTagWhitespace: true,
collapseWhitespace: true,
conservativeCollapse: false,
decodeEntities: true,
html5: true,
includeAutoGeneratedTags: false,
keepClosingSlash: false,
preserveLineBreaks: false,
preventAttributesEscaping: true,
processConditionalComments: false,
quoteCharacter: '"',
removeAttributeQuotes: true,
removeEmptyAttributes: true,
removeEmptyElements: false,
removeOptionalTags: true,
removeRedundantAttributes: true,
removeScriptTypeAttributes: true,
removeStyleLinkTypeAttributes: true,
sortAttributes: true,
sortClassName: true,
useShortDoctype: true,
}
let {minify} = this.options
if (minify) {
// Minify.
serialized = minifyHtml(serialized, {
minifyCSS: true,
minifyJS: true,
removeComments: true,
...MINIFIER_OPTIONS,
})
} else {
// Beautify.
serialized = minifyHtml(serialized, MINIFIER_OPTIONS)
serialized = beautifyHtml(serialized, {
indent_char: ' ',
indent_inner_html: true,
indent_size: 2,
sep: '\n',
unformatted: ['code', 'pre'],
})
}
return serialized
}
/**
* Load the template and parse it using Parse5.
*/
parseTemplate() {
log('Loading template...')
const SOURCE = readFileSync(this.options.template, 'utf8')
log('Parsing template...')
this.tree = parse(SOURCE)
log('Done loading and parsing template.')
}
async tapAfterCompile(compilation, done) {
console.log()
console.log()
for (let asset of compilation.modules) {
if (asset.rawRequest == 'assets/logo.svg')
console.log(asset)
}
console.log()
console.log()
// Add the template to the dependencies to trigger a rebuild on change in
// watch mode.
compilation.fileDependencies.add(this.options.template)
// Emit the final HTML.
const FINAL_HTML = this.getHtmlString()
compilation.assets['index.html'] = {
source: () => FINAL_HTML,
size: () => FINAL_HTML.length,
}
done()
}
async tapBeforeRun(compiler, done) {
this.parseTemplate()
// Add assets to the compilation.
for (let {context, path} of this.extractAssetPaths()) {
new PrefetchPlugin(context, path)
.apply(compiler)
}
done()
}
}
Found the answer, after I loaded the dependencies, I can access the generated module's source:
// Index the modules generated in the child compiler by raw request.
let byRawRequest = new Map
for (let asset of compilation.modules)
byRawRequest.set(asset.rawRequest, asset)
// Replace the template requests with the result from modules generated in
// the child compiler.
for (let {node, request} of this._getAssetRequests()) {
if (!byRawRequest.has(request))
continue
const ASSET = byRawRequest.get(request)
const SOURCE = ASSET.originalSource().source()
const NEW_REQUEST = execAssetModule(SOURCE)
setResourceRequest(node, NEW_REQUEST)
log(`Changed: ${prettyFormat({from: request, to: NEW_REQUEST})}`)
}
And execute the module's source with a VM:
function execAssetModule(code, path) {
let script = new Script(code)
let exports = {}
let sandbox = {
__webpack_public_path__: '',
module: {exports},
exports,
}
script.runInNewContext(sandbox)
return sandbox.module.exports
}

vue.js unit testing with Jest : Should I mock the HTLL5 audio element?

Testing an AudioPlayer vue component, which contains the HTML5 element , I wonder how to write my specs with Jest .
template
<audio id="player" ref="player" #ended="ended" #canplay="canPlay" :src="file"></audio>
If I use the following wrapper
const wrapper = mount(AudioPlayer, {
propsData: {
autoPlay: false,
file,
ended,
canPlay
}
});
How should I set the file property ? ( I want to pass an audio file from src/assets/audio/mysong.mp3 )
If I use shallowMount instead, should I mock the audio element ? which way ... as the audio element handles play(), pause(), mute() ... I am a little bit lost and I cannot find any post related to testing such component...
You can use an empty sound file to initialize the component, you can inline it using base64 data uri
const file = 'data:audio/wave;base64,UklGRjIAAABXQVZFZm10IBIAAAABAAEAQB8AAEAfAAABAAgAAABmYWN0BAAAAAAAAABkYXRhAAAAAA==';
const wrapper = mount(AudioPlayer, {
propsData: {
autoPlay: false,
file,
ended,
canPlay
}
});
see also:
Silent sound data uri?
i check how the Heading.vue parent component is setting up the file property, it's not a string or a file it's an Object from a computed method :
data() {
return {
file: "ultimo_desejo",
....
computed: {
<audioplayer id="audioplayer" v-if="listening" v-show="showAudioPlayer" :autoPlay="autoPlay" :file="audioFile" :canPlay="audioReady" :ended="switchAudioPlayer" #ended="switchAudioPlayer"></audioplayer>
....
and in the AudioPlayer child component
props: {
file: {
type: Object,
default: null
},
So I can set the props in my AudioPlayer.spec file
const file = require("#/assets/audio/ultimo_desejo.mp3");
const wrapper = mount(AudioPlayer, {
propsData: {
autoPlay: false,
file: file,
ended,
canPlay
}
});

mocking a require()'d imported object with jest/sinon

here's my code:
const Config = require('Config');
export const getPayments = (username: string) => {
if (username === undefined) {
throw new Error('username is undefined');
}
const envEndpoint = Config.paymentsEndpoint;
const endpoint: string = `${envEndpoint}/${username}`;
return fetch(endpoint);
};
What I want to mock is the Config object. I basically want to intercept that require call in my test file and replace it with a an object with that paymentsEndpoint value. I am using jest, but also have sinon as an option for mocking.
I am still fairly new to unit tests and jest, so forgive me if I used incorrect terminology
In your test file before you import your getPayments module, you can use jest.mock to mock the Config module.
So it would look something like
/* getPayments.test.js */
jest.mock('Config', () => {
return { paymentsEndpoint: 'y' }; // return your fake Config obj here
});
import getPayments from './getPayments'; // or whatever the correct file path is
describe(() => {
[ ... your tests ]
});
here are the jest.mock docs: https://facebook.github.io/jest/docs/en/jest-object.html#jestmockmodulename-factory-options