Locust is really focused on load tests (rather than acceptance tests). It's an alternative to ab rather than one to a headless browser.

You definitely wouldn't use Locust to test a UI, or even to test your API responds correctly, but you'd use it to know how many requests per second that API can serve without falling over.

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Two key differentiators (advantages?) Locust has over ab are:

+ It's scriptable, so you can design complex interactions like described in the blog post (or even something as simple as logging in prior to hitting the app).

+ It supports clustering. It's easy to setup a multi-host Locust cluster, and results are aggregated to your locust master.

I don't have an affiliation with Locust, but I did find it extremely easy to setup and use when I needed it (for HTTP load tests with ~20K RPS).

I do recall a few scale issues (e.g. running out of client ports would break the clustering), but with a bit of fine-tuning, it runs like a charm.

> What is the advantage of this over the variety of headless browsers and acceptance testing frameworks that currently exist?

Locust is a loadtesting tool. I have been using it for years now and from what I can see there is no reasonable alternative. If there is one, I would love to hear about it.

This was my thought as well. I guess it's a nice class for existing Python users to dive into performance testing with. Guys who have used Load Runner or something for years wouldn't use this but I might play with it since I am on the devops side and know Python.

For me it was the fact that it was python, relatively light, designed specifically for load testing, and was able to scale the number of users out of the box with minimal configuration.