mbtest

Opinionated Python wrapper & utils for the Mountebank over the wire test double tool.

Includes pytest fixture and PyHamcrest matchers.

Setup

Install with pip:

pip install mbtest

(As usual, use of a venv or virtualenv is recommended.) Also requires Mountebank to have been installed:

npm install mountebank@2.9 --omit=dev

(Alternatively, you can attach to an instance of Mountebank running elsewhere, perhaps in docker.)

Basic example

import requests
from hamcrest import assert_that
from brunns.matchers.response import is_response
from mbtest.matchers import had_request
from mbtest.imposters import Imposter, Predicate, Response, Stub

def test_request_to_mock_server(mock_server):
    # Set up mock server with required behavior
    imposter = Imposter(Stub(Predicate(path="/test"), 
                             Response(body="sausages")))

    with mock_server(imposter):
        # Make request to mock server - exercise code under test here
        response = requests.get(f"{imposter.url}/test")

        assert_that("We got the expected response", 
                    response, is_response().with_status_code(200).and_body("sausages"))
        assert_that("The mock server recorded the request", 
                    imposter, had_request().with_path("/test").and_method("GET"))

Needs a pytest fixture, most easily defined in conftest.py:

import pytest
from mbtest import server

@pytest.fixture(scope="session")
def mock_server(request):
    return server.mock_server(request)

This will take care of starting and stopping the Mountebank server for you. Examples of more complex predicates can be found in the integration tests.

See the Documentation for more.

Contributing

Requires make, uv, and Node.js (for Mountebank). Integration tests run against an instance of Mountebank running in Docker.

brew install colima docker uv node
colima status || colima start
uv sync --all-groups
npm install mountebank@2.9 --omit=dev

(mbtest is tested against Mountebank versions back as far as 1.16, but obviously only features supported by the Mountebank version you're using will work.)

After that, you should be ready to roll; running make test will let you know if your setup is correct.

Running make precommit tells you if you're OK to commit. For more options, run:

make help

Releasing

Update the version number in pyproject.toml and SECURITY.md, commit, then:

version="n.n.n"
git checkout -b "release-$version"
make precommit && git commit -am"Release $version" && git push --set-upstream origin "release-$version"
git tag "v$version" && git push origin "v$version"

Pushing the tag triggers the release workflow, which builds, tests, publishes to PyPI via OIDC, and creates the GitHub release automatically.

PyPI trusted publishing setup

Before the first automated release, a one-time setup is required.

On PyPI

1. Log in to pypi.org and navigate to the mbtest project.
2. Go to Manage → Publishing.
3. Under Add a new pending publisher, fill in:
   • PyPI project name: mbtest
   • Owner: brunns
   • Repository name: mbtest
   • Workflow name: release.yml
   • Environment name: pypi
4. Click Add.

On GitHub

In the repository Settings → Environments, create an environment named pypi. No secrets are needed — OIDC handles authentication automatically.