test: add coveralls

Author: crazyscot

.github/workflows/ci.yml

@@ -91,6 +91,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+      - uses: taiki-e/install-action@cargo-llvm-cov
       - uses: Swatinem/rust-cache@v2
         with:
           cache-on-failure: true
@@ -102,7 +103,17 @@ jobs:
         run: scripts/install-ubuntu-packages
       # Checks begin here!
       - run: cargo fmt --all --check
-      - run: cargo test --locked
+      #- run: cargo test --locked # replaced by cargo llvm-cov to run with coverage tests
       - run: cargo clippy --locked --all-targets
       - run: cargo build --locked --all-targets
       - run: cargo doc --no-deps --locked
+      - name: unit tests with coverage
+        run: cargo llvm-cov --all-features --workspace --lcov --output-path lcov.info --locked
+      - name: Upload coverage artifact
+        uses: actions/upload-artifact@v4
+        with:
+          path: lcov.info
+      - name: Send to coveralls
+        uses: coverallsapp/github-action@v2.3.4
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}

CONTRIBUTING.md

@@ -14,6 +14,7 @@ If you're thinking of contributing something non-trivial, it might be best to ra
 * Changes should normally be based on the `dev` branch. _(Exception: hotfixes may be branched against `main`.)_
 * PRs must pass the full set of CI checks (see below). No exceptions.
 * Unit tests are encouraged, particularly those which fail before and pass after a fix.
+  * The CI workflow runs code coverage analysis.
 * Refactoring for its own sake is OK if driven by a feature or bugfix.
 * Clean commit histories are preferred, but don't be discouraged if you don't know how to do this. git can be a tricky tool.
 * Commit messages should follow [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/).
@@ -32,6 +33,7 @@ If you're thinking of contributing something non-trivial, it might be best to ra
 | Unit tests pass | `cargo test` |
 | Lints | `cargo clippy --all-targets` | This is a reasonably pedantic set of lints, which I make no apologies for |
 | Docs build | `cargo doc --no-deps` |
+| Code coverage | `./scripts/coverage`, then examine `target/coverage/html` |
 
 
 [issue]: https://github.com/crazyscot/qcp/issues/new/choose