Frederick W. Taylor was a bastard, but it is helpful to keep track of the amount of time you spend on an activity if you're doing it for your own benefit. timestudy is here to help you in this endeavor.
timestudy intends to be an activity tracker similar to Timewarrior. It is mostly a project to help me expand my Rust skills, so you probably actually want Timewarrior, not this. (There are far fewer features at the moment, and probably far more bugs.) But perhaps someday it will be a decent alternative. A front-end GUI is currently being built in tandem: https://codeberg.org/kdwarn/ts-gui, and I also hope to build a CLI as well.
Features, enhancements, bugs, questions, and similar are tracked in issues. These are then distilled into milestones. I intend to regularly update the next two milestones as a way to think about and plan the next immediate things to do.
The library uses a feature that enables sharing of code between the integration tests and unit tests. To include the integration tests in a test run, use cargo test --features inttests.