cargo-cov: Source coverage for Rust

cargo-cov is a cargo subcommand which performs source coverage collection and reporting for Rust crates. cargo-cov utilizes LLVM's gcov-compatible profile generation pass, and supports a lot of platforms.

• ✓ FreeBSD, Linux, macOS, Windows (MSVC only)
• ✓ x86_64, x86

Usage: for Local Testing on nightly Rust

You may install cargo-cov via cargo.

cargo install cargo-cov

The typical workflow is like this:

# clean up previous coverage result
cargo cov clean

# test the code
cargo cov test

# open the coverage report
cargo cov report --open

Usage: for Testing on stable Rust (1.19+)

We strongly recommend you use nightly Rust since only the nightly toolchain has built-in instrumented profiling support via -Zprofile.

If you must use a stable toolchain, you may try the following:

1. Install the compiler-rt profile library.

   Target	Instruction
   Ubuntu, Debian	Install libclang-common-7-dev, or simply install clang
   Fedora	Install compiler-rt
   OpenSUSE	Install llvm-clang
   Windows (MSVC)	Install Clang for Windows Pre-Built Binary from LLVM
   macOS, iOS	Provided by the Xcode command line tools
   Android	Provided by Android NDK

2. Execute the doc-test separately from the normal tests. Run the doc-test before the normal tests.

   # Run --doc tests before other things before 1.19
   cargo cov test --doc
   cargo cov test --lib

We do not guarantee that a correct coverage profile will be generated using this method.