Tarpaulin is designed to be a code coverage reporting tool for the Cargo build system, named for a waterproof cloth used to cover cargo on a ship. Currently, tarpaulin provides working line coverage but is still in the early development stage and therefore may contain some bugs. A lot of work has been done to get it working on some example projects and smaller crates so please report anything you find that's wrong. Also, check out our roadmap for planned features.
Tarpaulin only supports x86/x86_64 processors running linux. This is because instrumenting breakpoints into executables and tracing their execution requires processor and OS specific code. It is a goal when greater stability is reached to add wider system support, however this is sufficient to run Tarpaulin on popular CI tools like Travis.
Below is a list of features currently implemented. As Tarpaulin loads binary files into memory and parses the debugging information, different setups could lead to coverage not working. In this instance, please raise an issue detailing your setup and an example project and I'll attempt to fix it (please link us to a repo and the commit containing your project and paste the verbose output).
Tarpaulin depends on cargo which depends on SSL. Make sure you've installed your distros ssl development libraries and they are on your path before attempting to install tarpaulin.
To get detailed help on available arguments when running tarpaulin call:
text
cargo tarpaulin --help
Currently no options are required, if no root directory is defined Tarpaulin will run in the current working directory.
Below is a Tarpaulin run utilising one of our example projects. This is a relatively simple project to test and if you check the test, you can see the output correctly reports the lines the test hits.
```text cargo tarpaulin -v Running Tarpaulin Finished dev [unoptimized + debuginfo] target(s) in 0.0 secs Processing simple_project Launching test
running 1 test test tests::bad_test ... ok
test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured
Coverage Results src/unused.rs:4 - hits: 0 src/unused.rs:5 - hits: 0 src/unused.rs:6 - hits: 0 src/unused.rs:7 - hits: 0 src/lib.rs:4 - hits: 1 src/lib.rs:5 - hits: 1 src/lib.rs:6 - hits: 0 src/lib.rs:8 - hits: 1 src/lib.rs:10 - hits: 1 src/lib.rs:21 - hits: 1 src/lib.rs:22 - hits: 1 src/lib.rs:23 - hits: 1
src/lib.rs: 7/8 src/unused.rs: 0/4
58.33% coverage, 7/12 lines covered ```
Hint: if using coveralls.io with travis-ci run with the options "--ciserver travis-ci --coveralls $TRAVISJOBID". The coveralls.io repo-token is mainly designed for private repos and it won't generate a badge for the coverage results submitted (although you can still see them on the coveralls web interface). For an example of a project using Tarpaulin, you can check out my crate keygraph-rs.
The expected most common usecase is launching coverage via a CI service to upload to a site like codecov or coveralls. Given the built in support and ubiquity of travis-ci it seems prudent to document the required steps here for new users. To follow these steps you'll first need a travis-ci and coveralls project for your repo.
We recommend taking the minimal rust .travis.yml, installing the libssl-dev dependency tarpaulin has and then after the clean, build and test with the stable compiler installing tarpaulin and running it on the cleaned project. The clean step shouldn't be necessary but it's just to make sure for people who may have more complicated build steps (i.e. code generation).
```text language: rust dist: trusty addons: apt: packages: - libssl-dev cache: cargo rust: - stable - beta - nightly matrix: allow_failures: - rust: nightly script: - cargo clean - cargo build - cargo test
aftersuccess: | if [[ "$TRAVISRUSTVERSION" == stable ]]; then cargo install cargo-tarpaulin cargo tarpaulin --ciserver travis-ci --coveralls $TRAVISJOB_ID fi ```
Tarpaulin has currently only been tested on small crates or projects. It is entirely possible issues could occur with larger or more complicated projects. Please raise any issues you find to help improve tarpaulin for everyone.
Tarpaulin is currently licensed under the terms of both the MIT license and the Apache License (Version 2.0). See LICENSE-MIT and LICENSE-APACHE for more details.
I wouldn't have been able to make progress as quickly in this project without Joseph Kain's blog on writing a debugger in Rust and C. It's a great read, so I recommend you check it out here.