HTTP test fixture helper

Usage no npm install needed!

<script type="module">
  import mapboxAssertHttp from 'https://cdn.skypack.dev/@mapbox/assert-http';


Assert HTTP

Test helpers for testing a HTTP interface. This library contains two primary interfaces; a test runner which executes a set of HTTP calls as described by files in a directory, and a extension to the assert module.

Build Status

HTTP testing inferface

With mocha, usage looks like;

describe('api server', function(done) {
    fixtures.load('/path/to/tests/').forEach(function(test) {
        it(test.name, function(done) {
            fixtures.runtest(test, {handlers: handlers, clean: clean}, done);


Syncronous function that loads text fixtures from a directory. Returns an array of test objects.

assertHTTP.runtest(test, options, callback)

Runs an individual test. Requires a test object (from assertHTTP.load), options object and callback function. The options object may contain the keys;

  • handlers; an object of keys and replacer methods for populating http requests. Handlers are async and have the function signature function(req, value, next)
  • clean; an object of keys and replacer methods for sanitizing http response headers and body. Replacer methodes have the signature function(key, value, context)


Call this method to notify assertHTTP to update fixtures as it runs.


Sync version of mkdirp


md5 helper.

assertHTTP.imageEquals(buffer, buffer, options)

A pixel-by-pixel comparison of two image buffers using the node-mapnik Image.compare() API. The options object may contain the keys:

  • threshold; tolerance level of RGB value difference between two pixels. Defaults to 16.
  • diffsize; a float between 0-1 expressing the max allowed difference between buffer lengths. Defaults to 0.1.
  • diffpx; a float between 0-1 expressing the max number of pixels allowed to exceed the threshold option. Defaults to 0.02.

Assertion module extension

assert.response(req, res, callback)

If res.clean is present it is expected to be a method that json.stringify can use to sanitize the response headers.