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nuntius is an Erlang/OTP library to mock registered processes. Its main use case is to intercept messages sent to specific processes and to allow the consumer to act upon them.

usage

Usage

nuntius is best used via rebar3's test profile and using Erlang/OTP's Common Test framework:

1. change your rebar.config to include:

{profiles, [{test, [{deps, [nuntius]}]}]}.

2. run your nuntius-enabled tests with:

rebar3 ct

features

Features

  • places mock processes in front of previously registered processes; these mock processes will intercept (and optionally handle) every message that was supposed to go to the latter ones, then
    • allows mock processes to decide on letting the messages pass through, or not,
    • allows mock processes to run one or many pre-processing functions on each received message,
    • allows mock processes to discard intercepted messages entirely,
    • allows history collection of messages received by the mock processes for further analysis.

options-for-the-mock-process

Options for the mock process

The following parameters allow you to configure the interaction between the mock and mocked processes, as well as other elements for debugging:

  • passthrough: when true (default: true) all messages received by the mock process are passed through to the mocked process,
  • history: when true (default: true) all messages received by the mock process are classified as per Understanding the message history.

understanding-the-message-history

Understanding the message history

History elements are classified with 4 keys:

  • timestamp: an integer representing Erlang system time in native time unit,
  • message: the message that was received and/or potentially handled by expectations (or passed through),
  • mocked: an indication of whether or not any of the expecations you declared handled the message,
  • passed_through: an indication of whether or not the received message was passed through to the mocked process.

caveats

Caveats

nuntius tries to execute your expectations by simply calling their declarations inside a try-catch expression. Because of this, non-matching expectations will return a function_clause, that is caught. Since it's not possible (at this moment) to distinguish a function_clause provoked by nuntius' internal code or your own, we propose you to make sure your functions don't fail with a function_clause. You can also check the message history to understand if a given message was mocked and/or passed through.

documentation

Documentation

Documentation is generated with:

rebar3 edoc

after which you can use your favorite Web browser to open doc/index.html.

It is also available, online, at hexdocs.pm/nuntius.

examples

Examples

Examples are found at examples.

versioning

Versioning

This project adheres to Semantic Versioning.

readme

Readme

We get inspiration for our README's format/content from Make a README.

changelog

Changelog

All notable changes to this project will be referenced from the CHANGELOG.

contributing

Contributing

Though this project is maintained by 2Latinos contributions are accepted and welcome. Check CONTRIBUTING.md for more.

license

License

Check LICENSE.