This project is a command line universal behavior testing tool inspired by rere.py. I was inspired by the simple, elegant solution presented in the original project to the problem of universal testing, but wanted a compiled binary for more ubiquitous and comprehensive usage. This project provides a significant extension on top of the original concept. The rere tool makes use of the bi format, a simple structured human readable binary format.

The project is split into two parts:

1. bi-parser: A library crate providing functionality for validating, reading, and writing bi formatted files.
2. rere-app: A binary crate which uses the bi-parser library to create the actual command line tool.

1. Download the release binary or build the crate from source.
2. From your project's root directory, run rere init, this will create:
   • A config at rere/rere.toml
   • A directory to store the record snapshots at rere/snapshots/
   • A test file at rere/test.list
3. Add some shell commands to the test file (i.e. echo "Hello World!).
4. Record the expected behavior with rere record. This will create the .bi snapshot file here: rere/snapshots/test.list.bi.
5. Later, you can run rere replay to replay the test file (the default fail_fast setting is true so the replay will report the first difference, if any, and exit).

Much more comprehensive usage documentation can be found here .

Note: All these features are configurable either through command line arguments or by manually building/editing the .toml config file.

Several features over the original project were built into the rere.rs app, including:

• Command line tool
• Config file for persisting and tracking testing configurations
• Init command functionality for easy test structure setup and cleanup
• Dedicated snapshot and recording directory
• Ability to version snapshot files for testing history
• Basic metadata tracking
• Fast fail options for snapshot replaying
• Single line comment (//) support in test files

In addition, this project supports a minor extension on original the bi format:

• A signed integer marker type (:s)

• Ability to capture file system changes (for testing scripts that write to log files instead of to stdout)
• Additional metadata tracking
• Warnings if significant deviation from previous processing times
• Standardized readme
• Tab completions