SM JavaScript test utilities

Package to help mock Endpoints, functions and middleware for Express and Azure Functions, without having to spin up a webserver.

This package was previously named azure-function-mocker. However, because we have added utilities for Express applications as well, has the package been renamed to sm-js-test-utils.

This package is maintained by the organization Studentmedia in Trondheim inc., hence the sm prefix in the name. Any feedback, questions or change-requests can be issued on the projects github page. However, feel free to open pull requests with the changes implemented.

Installation

npm install --save-dev sm-js-test-utils

API-reference

Since the module contains utilities for both express and azure functions, are their respective features grouped together.

• Azure Functions utilities are located in azfun
• Express utilities are located in express.

Request Mocker (azfun)

Creates a mocked HttpRequest, which is accepted as an argument by FunctionMocker.run.

Parameters

name	type	Null	description	legal values
method	string	Yes	The HTTP method to mock	POST, GET, PUT, PATCH, HEAD, OPTION
params	object	Yes	The URL parameters to include	All key-value objects
query	object	Yes	The Query parameteres to include	All key-value objects

Examples

Simple GET request

const { mockRequest } = require('sm-js-test-utils').azure;

const req = mockRequest(); // GET, could also be explicitt and write it in.

Simple request with non-GET method

const { mockRequest } = require('sm-js-test-utils').azure;

const req = mockRequest('POST'); // or 'PUT', 'PATCH', 'HEAD', 'OPTION', ...

Function Mocker (azfun)

Creates a mocked environment for which the function can run in. Simply said appends a mocked context to the first function parameter, and returns the updated context when the function has completed.

Examples

Simple HttpTriggered function

The most simple use-case to mock a function. getHelloWorld takes no other arguments than the required context-argument, and returns a simple HTTP 200 response with the body { message: 'Hello world' }

const { FunctionMocker } = require('sm-js-test-utils').azure;

function getHelloWorld(context) {
    context.res = {
        status: 200,
        body: { message: 'Hello world' }
    };
    context.done();
}

const func = new FunctionMocker(getHelloWorld);

const ctx = await func.run();

console.log(ctx.res.status); // 200
console.log(ctx.res.body); // { message: 'Hello world' }

HttpTriggered function with request object

A more complex version of the previous example, but yet quite simple.

const { FunctionMocker, mockRequest } = require('sm-js-test-utils').azure;

function postHelloWorld(context, req) {
    if (!req.params.name) {
        context.res = {
            status: 400,
            body: { error: 'Missing name!' }
        };
    } else {
        context.res = {
            status: 200,
            body: { message: `Hello ${req.params.name}`}
        };
    }

    context.done();
}

const req = mockRequest('POST', { name: 'Jon Snow' }); // Mocks a request with a POST-body

const func = new FunctionMocker(postHelloWorld);

const ctx = await func.run(req);

console.log(ctx.res.body); // { messsage: 'Hello Jon Snow' }

HttpTriggered function returning a Promise

An Azure Function also supports ending the function through Promise.resolve(). We will in this example use async/await, as it saves us syntax-space, the function will in reality return a promise (see ES2017 spec for more details).

const { FunctionMocker } = require('sm-js-test-utils').azure;

async function getHelloWorld(context) {
    context.res = {
        status: 200,
        body: { message: 'Hello Async World' }
    };
}

const func = new FunctionMocker(getHelloWorld);

const ctx = await func.run();

console.log(ctx.res.body); // { message: 'Hello Async World' }

As we see, there is no practical difference for the FunctionMocker, and what your output after func.run() is.

Context Mocker (azfun)

Function which takes an callback-function, that is called when the Azure Function completes by using context.done()

Note: Azure Functions also supports the use of promises, thus an function can complete by calling Promise.resolve(), which won't trigger the callback-function

const { mockContext } = require('sm-js-test-utils').azure;

// Alternative 1
mockContext((updatedContext) => {
    // Do some operation with the context.
});

// Alternative 2
// Usefull when working with async/await
const context = mockContext((updatedContext) => {
    // Do some operation with the context.
});

The last alternative is usefull when working with async/await, as the constant context will also contain the updated values.

You will however, rarelly need to work directly with mockContext() as FunctionMocker does this for you.

Contribution

1. Clone the repository
2. Run npm install
3. Write your code
4. Write tests to your changes
5. Lint your code
6. Open a pull request
7. Wait for feedback and QA
8. Merge and Glory!

Submitting issues

Add a new issue in the issues tab. Write as detailed as you can

Known issues

A list of known issues. More details can typically be found on github.

mockContext()

1. Problem with context.log() and context.log.info(). Having issues with properly mocking context.log, as it can be both an function context.log() and an object context.log = { info: ..., error: ..., warn: ..., verbose: ... }. Have therefore only included support for the "object" version of it, as it provides the most features.