apolitical/rust-kcov repository overview

⁠Rust-kcov

Provides coverage reports for your Rust projects using kcov.

⁠Usage:

⁠Running the container:

$ docker run --rm -it -v "$PWD":/app --security-opt seccomp=unconfined apolitical/rust-kcov

Explained:

• --rm to automatically remove the container when finished
• -it to bind the terminal (not needed if you're going tell the container what command to run)
• -v "$PWD":/app bind the current working directory of the host to the /app directory inside the container. Note: /app is the default working directory we've set in the Dockerfile. If you want to put your app somewhere else, you can use -v "$PWD":/elsewhere -w /elsewhere to change the working directory.
• --security-opt seccomp=unconfined allows kcov to change the personality of the file being run, this unfortunately seems to be required.

⁠Once you're in the container:

Build the tests but don't run them yet

$ cargo test --no-run

This will have to download all dependencies unless you've somehow included them in your project directory.

$ shopt -s extglob
$ kcov --include-pattern=src --verify target/cov target/debug/<your-app-name>-+([[:alnum:]])

Explained:

• shopt is for shell options, -s is to turn an option on, extglob is for extended pattern
• --include-pattern is used to limit which files will be included in the report (without it, it will report on all dependencies etc, which isn't useful information and will throw off coverage %)
• --verify checks for problems when the app was compiled, weirdly kcov doesn't work on Rust without it.
• You must then provide two locations:
  1. Where your coverage report to go, in this case target/cov
  2. The file to run. When cargo test runs it will create a file named after your project but with some random characters after it, but it creates a second file, almost the same but with a .d after it. This means you cannot use <your-app-name>-* because kcov will fail. Using extglob though, we're able to select a file with an alpha numeric suffix (i.e. no .).

⁠Contributing

This is a very loosely cobbled together project, I really hope you'll find it useful. If you have any problems with it, please open an issue. If you'd like to make a Pull Request please do! Checkout the Contributing⁠ guide and Code of Conduct⁠ for more information.