# Tarpaulin
[](https://travis-ci.org/xd009642/tarpaulin)[](https://crates.io/crates/cargo-tarpaulin)[](https://opensource.org/licenses/MIT)[](https://hub.docker.com/r/xd009642/tarpaulin/)
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_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.
It can also be run in Docker, which is useful for when you don't use Linux but
want to run it locally, e.g. during development. See below for how to do that.
**Due to unstable features in syn and issues with not packaging tarpaulin with
the Cargo.lock file tarpaulin is now a nightly only crate. If you don't run
nightly by default replace all calls to `cargo tarpaulin` with
`cargo +nightly tarpaulin`**
## Features
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).
* Line coverage
* Uploading coverage to https://coveralls.io or https://codecov.io
## Usage
### Installation
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. For example for Debian/Ubuntu:
```text
apt-get update && apt-get install libssl-dev pkg-config cmake zlib1g-dev
```
Tarpaulin is a command-line program, you install it into your linux development
environment with cargo install:
```text
RUSTFLAGS="--cfg procmacro2_semver_exempt" cargo install cargo-tarpaulin
```
Because of the `syn` dependency you need the following `RUSTFLAGS` to enable
the semver exempt functionality to report positions in the source code.
Alternatively, you can use the docker develop images or the prebuilt github releases
for travis-ci.
### Command line
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
Cleaning project
Building project
Compiling simple_project v0.1.0 (/home/xd009642/code/rust/tarpaulin/tests/data/simple_project)
Finished dev [unoptimized + debuginfo] target(s) in 0.31s
Processing simple_project
Launching test
running /home/xd009642/code/rust/tarpaulin/tests/data/simple_project/target/debug/deps/simple_project-a387d41cf984eb4b
running 1 test
test tests::bad_test ... ok
test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
Coverage Results
Uncovered Lines:
src/lib.rs: 6
src/unused.rs: 4-6
Tested/Total Lines:
src/lib.rs: 5/6
src/unused.rs: 0/3
55.56% coverage, 5/9 lines covered
Tarpaulin finished
```
Hint: if using coveralls.io with travis-ci run with the options
`--ciserver travis-ci --coveralls $TRAVIS_JOB_ID`. The coveralls.io repo-token
is mainly designed for private repos and it won't generate a badge for the
coverage results submitted (although you can still see them on the coveralls
web interface). For an example of a project using Tarpaulin, you can check out
my crate [keygraph-rs](https://github.com/xd009642/keygraph-rs).
### Ignoring code in files.
Tarpaulin now allows you to ignore modules or functions using config attributes.
Below is an example of ignoring the main function in a project:
```Rust
#[cfg_attr(tarpaulin, skip)]
fn main() {
println!("I won't be included in results");
}
```
### Travis-ci and Coverage Sites
The expected most common usecase is launching coverage via a CI service to
upload to a site like codecov or coveralls. Given the built in support and
ubiquity of travis-ci it seems prudent to document the required steps here for
new users. To follow these steps you'll first need a travis-ci and a project setup
for your coverage reporting site of choice.
We recommend taking the minimal rust .travis.yml, installing the libssl-dev
dependency tarpaulin has and then running Tarpaulin with the version of
rustc you require. Tarpaulin is installed in `before_cache` to allow it to be cached
and prevent having to reinstall every Travis run. You can also replace `cargo test`
with a verbose run of tarpaulin to see the test results as well as coverage output.
For codecov.io you'll need to export CODECOV_TOKEN are instructions on this in
the settings of your codecov project.
```yml
language: rust
sudo: required
dist: trusty
addons:
apt:
packages:
- libssl-dev
cache: cargo
rust:
- stable
- beta
- nightly
matrix:
allow_failures:
- rust: nightly
before_cache: |
if [[ "$TRAVIS_RUST_VERSION" == nightly ]]; then
RUSTFLAGS="--cfg procmacro2_semver_exempt" cargo install cargo-tarpaulin
fi
script:
- cargo clean
- cargo build
- cargo test
after_success: |
if [[ "$TRAVIS_RUST_VERSION" == nightly ]]; then
# Uncomment the following line for coveralls.io
# cargo tarpaulin --ciserver travis-ci --coveralls $TRAVIS_JOB_ID
# Uncomment the following two lines create and upload a report for codecov.io
# cargo tarpaulin --out Xml
# bash <(curl -s https://codecov.io/bash)
fi
```
Alternative, there is the travis-install shell script will install the latest tagged
release built on travis to your travis instance and significantly speeds up the travis
builds. You can install via that script using
`bash <(curl https://raw.githubusercontent.com/xd009642/tarpaulin/master/travis-install.sh)`.
**Warning** due to the proc_macro2 dependency, the github releases are now tied
to a specific version of rust so are no longer recommended. Instead use cargo or docker to
install tarpaulin.
### Docker
Tarpaulin has builds deployed to [docker-hub](https://hub.docker.com/r/xd009642/tarpaulin/),
to run Tarpaulin on any system that has Docker, run this in your project directory:
```text
docker run --security-opt seccomp=unconfined -v "$PWD:/volume" xd009642/tarpaulin
```
This builds your project inside Docker and runs Tarpaulin without any arguments. There are
also tags available for the latest version on the develop branch in stable or nightly. And
versions after 0.5.6 will have the latest release built with the rust stable and nightly
compilers. To get the latest development version built with rustc-nightly run the following:
```text
docker run --security-opt seccomp=unconfined -v "$PWD:/volume" xd009642/tarpaulin:develop-nightly
```
Note that the build might fail if the Docker image doesn't contain any necessary
dependencies. In that case, you can install dependencies before, like this:
```text
docker run --security-opt seccomp=unconfined -v "$PWD:/volume" xd009642/tarpaulin sh -c "apt-get install xxx && cargo tarpaulin"
```
## Extending Tarpaulin.
There are some tools available which can extend tarpaulin functionality for
other potential user needs.
### Procedural Macros
Normally, Tarpaulin can't report on code coverage within the code for a
procedural macro. You'll need to add a test that expands the macro at run-time
in order to get those stats. The
[`runtime-macros` crate](https://crates.io/crates/runtime-macros) was made for
this purpose, and its documentation describes how to use it with Tarpaulin.
### Pycobertura
[`pycobertura`](https://pypi.python.org/pypi/pycobertura) is a python library
for working with cobertura reports. It offers a report diffing tool as well as
it's own report implementations.
To generate a `cobertura.xml` simply run the following tarpaulin command:
```text
cargo tarpaulin --out Xml
```
Then install `pycobertura` with pip and execute the desired command.
As tarpaulin doesn't allow you to change the name of the generated cobertura
report be mindful of this if diffing reports between multiple commits.
## Issues and Contributing
Issues, feature requests and pull requests are always welcome! For a guide on
how to approach bugs found in Tarpaulin and adding features please check
[CONTRIBUTING](CONTRIBUTING.md).
Rust 1.23 introduced a regression in the compiler affecting tarpaulin's
accuracy. If you see missing lines or files, check your compiler version.
## Roadmap
- [x] Line coverage for tests
- [ ] Branch coverage for tests
- [ ] Condition coverage for tests
- [ ] Annotated coverage reports
- [x] Coverage reports in the style of existing tools (i.e. kcov)
- [x] Integration with 3rd party tools like coveralls or codecov
- [ ] Optional coverage statistics for doctests
- [ ] MCDC coverage reports
## License
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.
## Thanks
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](http://system.joekain.com/debugger/).