Azure Function Mocker

Service used to mock Azure Functions in testing environment. Built to complement the Jest library, but should not be dependant on it.

Installation

npm install --save-dev azure-function-mocker

API-reference

Request Mocker

Creates a mocked HttpRequest, which is accepted 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('azure-function-mocker');

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

Simple request with non-GET method

const { mockRequest } = require('azure-function-mocker');

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

Function Mocker

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('azure-function-mocker');

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('azure-function-mocker');

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('azure-function-mocker');

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

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('azure-function-mocker');

// 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

Submitting issues

Add a new issue in the issues tab, and write as detailed as you can

Known issues

List of known issues, more details exists in the issues tab.

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.

mockRequest()

FunctionMocker