ci: Add coverage collection configuration

.github/workflows/ci.yml

@@ -20,8 +20,22 @@ jobs:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: stable
+          toolchain: nightly
+          override: true
       - uses: actions-rs/cargo@v1
         with:
           command: test
-          args: --all-features
+          args: --all-features --no-fail-fast
+        env:
+          CARGO_INCREMENTAL: '0'
+          RUSTFLAGS: '-Zprofile -Ccodegen-units=1 -Cinline-threshold=0 -Clink-dead-code -Coverflow-checks=off -Cpanic=abort -Zpanic_abort_tests'
+          RUSTDOCFLAGS: '-Zprofile -Ccodegen-units=1 -Cinline-threshold=0 -Clink-dead-code -Coverflow-checks=off -Cpanic=abort -Zpanic_abort_tests'
+      - uses: actions-rs/[email protected]
+        id: coverage
+        with:
+          config: grcov.yml
+      - name: Coveralls upload
+        uses: coverallsapp/github-action@master
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          path-to-lcov: ${{ steps.coverage.outputs.report }}

README.md

@@ -1,5 +1,6 @@
 # generic-merge
 
 [![CI](https://github.com/jpedroh/generic-merge/actions/workflows/ci.yml/badge.svg)](https://github.com/jpedroh/generic-merge/actions/workflows/ci.yml)
+[![Coverage Status](https://coveralls.io/repos/github/jpedroh/generic-merge/badge.svg)](https://coveralls.io/github/jpedroh/generic-merge)
 
 An experiment to build a generic semi-structure merge algorithm

grcov.yml

@@ -0,0 +1,6 @@
+branch: true
+ignore-not-existing: true
+llvm: true
+filter: covered
+output-type: lcov
+output-path: ./lcov.info