Cargo subcommand to easily use LLVM source-based code coverage.
This is a wrapper around rustc -C instrument-coverage
and provides:
- Generate very precise coverage data. (line coverage and region coverage)
- Support both
cargo test
andcargo run
. - Support for proc-macro, including coverage of UI tests.
- Support for doc tests. (this is currently optional and requires nightly, see #2 for more)
- Command-line interface compatible with cargo.
Table of Contents:
Click to show a complete list of options
$ cargo llvm-cov --help
cargo-llvm-cov
Cargo subcommand to easily use LLVM source-based code coverage (-C instrument-coverage).
Use -h for short descriptions and --help for more details.
USAGE:
cargo llvm-cov [OPTIONS] [-- <ARGS>...] [SUBCOMMAND]
ARGS:
<ARGS>...
Arguments for the test binary
OPTIONS:
--json
Export coverage data in "json" format
If --output-path is not specified, the report will be printed to stdout.
This internally calls `llvm-cov export -format=text`. See
<https://llvm.org/docs/CommandGuide/llvm-cov.html#llvm-cov-export> for more.
--lcov
Export coverage data in "lcov" format
If --output-path is not specified, the report will be printed to stdout.
This internally calls `llvm-cov export -format=lcov`. See
<https://llvm.org/docs/CommandGuide/llvm-cov.html#llvm-cov-export> for more.
--text
Generate coverage report in “text” format
If --output-path or --output-dir is not specified, the report will be printed to stdout.
This internally calls `llvm-cov show -format=text`. See
<https://llvm.org/docs/CommandGuide/llvm-cov.html#llvm-cov-show> for more.
--html
Generate coverage report in "html" format
If --output-dir is not specified, the report will be generated in `target/llvm-cov/html`
directory.
This internally calls `llvm-cov show -format=html`. See
<https://llvm.org/docs/CommandGuide/llvm-cov.html#llvm-cov-show> for more.
--open
Generate coverage reports in "html" format and open them in a browser after the
operation.
See --html for more.
--summary-only
Export only summary information for each file in the coverage data
This flag can only be used together with either --json or --lcov.
--output-path <PATH>
Specify a file to write coverage data into.
This flag can only be used together with --json, --lcov, or --text. See --output-dir for
--html and --open.
--output-dir <DIRECTORY>
Specify a directory to write coverage report into (default to `target/llvm-cov`).
This flag can only be used together with --text, --html, or --open. See also --output-
path.
--failure-mode <any|all>
Fail if `any` or `all` profiles cannot be merged (default to `any`)
--ignore-filename-regex <PATTERN>
Skip source code files with file paths that match the given regular expression
--hide-instantiations
Hide instantiations from report
--no-cfg-coverage
Unset cfg(coverage)
--no-report
Run tests, but don't generate coverage report
--fail-under-lines <MIN>
Exit with a status of 1 if the total line coverage is less than MIN percent
--show-missing-lines
Show lines with no coverage
--doctests
Including doc tests (unstable)
This flag is unstable. See <https://github.com/taiki-e/cargo-llvm-cov/issues/2> for
more.
--no-run
Generate coverage report without running tests
--no-fail-fast
Run all tests regardless of failure
-q, --quiet
Display one character per test instead of one line
--lib
Test only this package's library unit tests
--bin <NAME>
Test only the specified binary
--bins
Test all binaries
--example <NAME>
Test only the specified example
--examples
Test all examples
--test <NAME>
Test only the specified test target
--tests
Test all tests
--bench <NAME>
Test only the specified bench target
--benches
Test all benches
--all-targets
Test all targets
--doc
Test only this library's documentation (unstable)
This flag is unstable because it automatically enables --doctests flag. See
<https://github.com/taiki-e/cargo-llvm-cov/issues/2> for more.
-p, --package <SPEC>
Package to run tests for
--workspace
Test all packages in the workspace
[aliases: all]
--exclude <SPEC>
Exclude packages from both the test and report
--exclude-from-test <SPEC>
Exclude packages from the test (but not from the report)
--exclude-from-report <SPEC>
Exclude packages from the report (but not from the test)
-j, --jobs <N>
Number of parallel jobs, defaults to # of CPUs
--release
Build artifacts in release mode, with optimizations
--profile <PROFILE-NAME>
Build artifacts with the specified profile
--features <FEATURES>
Space or comma separated list of features to activate
--all-features
Activate all available features
--no-default-features
Do not activate the `default` feature
--target <TRIPLE>
Build for the target triple
When this option is used, coverage for proc-macro and build script will not be displayed
because cargo does not pass RUSTFLAGS to them.
-v, --verbose
Use verbose output
Use -vv (-vvv) to propagate verbosity to cargo.
--color <WHEN>
Coloring
[possible values: auto, always, never]
--remap-path-prefix
Use --remap-path-prefix for workspace root
Note that this does not fully compatible with doctest.
--manifest-path <PATH>
Path to Cargo.toml
--frozen
Require Cargo.lock and cache are up to date
--locked
Require Cargo.lock is up to date
--offline
Run without accessing the network
-Z <FLAG>
Unstable (nightly-only) flags to Cargo
-h, --help
Print help information
-V, --version
Print version information
SUBCOMMANDS:
run
Run a binary or example and generate coverage report
show-env
Output the environment set by cargo-llvm-cov to build Rust projects
clean
Remove artifacts that cargo-llvm-cov has generated in the past
nextest
Run tests with cargo nextest
help
Print this message or the help of the given subcommand(s)
By default, run tests (via cargo test
), and print the coverage summary to stdout.
cargo llvm-cov
To run cargo run
instead of cargo test
, use run
subcommand.
cargo llvm-cov run
With html report (the report will be generated to target/llvm-cov/html
directory):
cargo llvm-cov --html
open target/llvm-cov/html/index.html
or
cargo llvm-cov --open
With plain text report (if --output-path
is not specified, the report will be printed to stdout):
cargo llvm-cov --text | less -R
With json report (if --output-path
is not specified, the report will be printed to stdout):
cargo llvm-cov --json --output-path cov.json
With lcov report (if --output-path
is not specified, the report will be printed to stdout):
cargo llvm-cov --lcov --output-path lcov.info
You can get a coverage report in a different format based on the results of a previous run by using --no-run
.
cargo llvm-cov --html # run tests and generate html report
cargo llvm-cov --no-run --lcov # generate lcov report
You can merge the coverages generated under different test conditions by using --no-report
and --no-run
.
cargo llvm-cov clean --workspace # remove artifacts that may affect the coverage results
cargo llvm-cov --no-report --features a
cargo llvm-cov --no-report --features b
cargo llvm-cov --no-run --lcov
In combination with the show-env
subcommand, coverage can also be produced from arbitrary binaries:
source <(cargo llvm-cov show-env --export-prefix)
cargo llvm-cov clean --workspace # remove artifacts that may affect the coverage results
cargo build # build rust binaries
# commands using binaries in target/debug/*, including `cargo test`
# ...
cargo llvm-cov --no-run --lcov # generate report without tests
To exclude specific file patterns from the report, use the --ignore-filename-regex
option.
cargo llvm-cov --open --ignore-filename-regex build
Here is an example of GitHub Actions workflow that uploads coverage to Codecov.
name: Coverage
on: [pull_request, push]
jobs:
coverage:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v2
- name: Install Rust
run: rustup toolchain install stable --component llvm-tools-preview
- name: Install cargo-llvm-cov
uses: taiki-e/install-action@cargo-llvm-cov
- name: Generate code coverage
run: cargo llvm-cov --all-features --workspace --lcov --output-path lcov.info
- name: Upload coverage to Codecov
uses: codecov/codecov-action@v1
with:
token: ${{ secrets.CODECOV_TOKEN }} # not required for public repos
files: lcov.info
fail_ci_if_error: true
Note: Currently, only line coverage is available on Codecov. This is because -C instrument-coverage
does not support branch coverage and Codecov does not support region coverage. See also #8, #12, and #20.
To exclude the specific function from coverage, use the #[no_coverage]
attribute.
Since #[no_coverage]
is unstable, it is recommended to use it together with cfg(coverage)
set by cargo-llvm-cov.
#![cfg_attr(coverage, feature(no_coverage))]
#[cfg_attr(coverage, no_coverage)]
fn exclude_from_coverage() {
// ...
}
cargo-llvm-cov requires llvm-tools-preview:
rustup component add llvm-tools-preview
Running cargo-llvm-cov requires rustc 1.60+.
cargo install cargo-llvm-cov
Currently, installing cargo-llvm-cov requires rustc 1.54+.
You can download prebuilt binaries from the Release page. Prebuilt binaries are available for macOS, Linux (gnu and musl), and Windows (static executable).
You can use taiki-e/install-action to install prebuilt binaries on Linux, macOS, and Windows. This makes the installation faster and may avoid the impact of problems caused by upstream changes.
- uses: taiki-e/install-action@cargo-llvm-cov
When used with nextest:
- uses: taiki-e/install-action@cargo-llvm-cov
- uses: taiki-e/install-action@nextest
You can install cargo-llvm-cov using Homebrew tap on macOS and Linux:
brew install taiki-e/tap/cargo-llvm-cov
You can install cargo-llvm-cov from AUR:
paru -S cargo-llvm-cov
Note: AUR package is maintained by community, not maintainer of cargo-llvm-cov.
- Branch coverage is not supported yet. See #8 and rust-lang/rust#79649 for more.
- Support for doc tests is unstable and has known issues. See #2 and rust-lang/rust#79417 for more.
See also the code-coverage-related issues reported in rust-lang/rust.
- cargo-hack: Cargo subcommand to provide various options useful for testing and continuous integration.
- cargo-minimal-versions: Cargo subcommand for proper use of
-Z minimal-versions
.
Licensed under either of Apache License, Version 2.0 or MIT license at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.