Track code coverage with cargo-llvm-cov and codecov.io (#277)

* Track code coverage with `cargo-llvm-cov`

* Add changelog entry

* Add coverage badge to the README

.changelog/unreleased/improvements/277-code-coverage.md

@@ -0,0 +1,2 @@
+- Track code coverage with `cargo-llvm-cov`
+  ([#277](https://github.com/cosmos/ibc-rs/issues/277))

.github/workflows/coverage.yml

@@ -0,0 +1,52 @@
+name: Coverage
+on:
+  pull_request:
+    paths:
+      - .github/workflows/rust.yml
+      - .github/workflows/coverage.yml
+      - Cargo.toml
+      - ci/**
+      - crates/**
+  push:
+    branches:
+      - master
+
+permissions:
+  contents: read
+
+concurrency:
+  group: rust-ci-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  CARGO_INCREMENTAL: 0
+  CARGO_PROFILE_DEV_DEBUG: 1
+  CARGO_PROFILE_RELEASE_DEBUG: 1
+  RUST_BACKTRACE: short
+  CARGO_NET_RETRY: 10
+  RUSTUP_MAX_RETRIES: 10
+  CARGO_TERM_COLOR: always
+
+jobs:
+  coverage:
+    name: Code Coverage
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Install Rust
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          override: true
+      - name: Install cargo-llvm-cov
+        uses: taiki-e/install-action@cargo-llvm-cov
+      - name: Install cargo-nextest
+        uses: taiki-e/install-action@nextest
+      - name: Generate code coverage
+        run: cargo llvm-cov nextest --all-features --lcov --output-path lcov.info
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v3
+        with:
+          files: lcov.info
+          fail_ci_if_error: true
+

README.md

@@ -4,6 +4,7 @@
 
 [![Docs][docs-image]][docs-link]
 [![Build Status][build-image]][build-link]
+[![Code Coverage][codecov-image]][codecov-link]
 [![Apache 2.0 Licensed][license-image]][license-link]
 ![Rust Stable][rustc-image]
 ![Rust 1.60+][rustc-version]
@@ -51,6 +52,8 @@ CONDITIONS OF ANY KIND, either express or implied. See the License for the speci
 [docs-link]: https://docs.rs/ibc/
 [build-image]: https://github.com/cosmos/ibc-rs/workflows/Rust/badge.svg
 [build-link]: https://github.com/cosmos/ibc-rs/actions?query=workflow%3ARust
+[codecov-image]: https://codecov.io/gh/cosmos/ibc-rs/branch/main/graph/badge.svg?token=wUm2aLCOu
+[codecov-link]: https://codecov.io/gh/cosmos/ibc-rs
 [license-image]: https://img.shields.io/badge/license-Apache2.0-blue.svg
 [license-link]: https://github.com/cosmos/ibc-rs/blob/main/LICENSE
 [rustc-image]: https://img.shields.io/badge/rustc-stable-blue.svg