Add code coverage CI job

.github/workflows/unit-test-on-pull-request.yml

@@ -71,3 +71,50 @@ jobs:
       - name: Run Benchmarks
         run: |
           GOMAXPROCS=100 make bench
+
+  coverage:
+    name: Coverage
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: true
+      max-parallel: 2
+      matrix:
+        go: ["stable"]
+    permissions:
+      contents: write
+    steps:
+      - name: Set up Go ${{matrix.go}}
+        uses: actions/setup-go@v4
+        with:
+          go-version: ${{matrix.go}}
+          check-latest: true
+        id: go
+      - name: Check out
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.head_ref }}
+      - name: Build
+        run: |
+          go install
+      - name: Run Coverage
+        run: |
+          go test -v -cover ./... -coverprofile coverage.out -coverpkg ./...
+          go tool cover -func coverage.out -o coverage.out  # Replaces coverage.out with the analysis of coverage.out
+
+      - name: Go Coverage Badge
+        uses: tj-actions/coverage-badge-go@v1
+        # if: ${{ runner.os == 'Linux' && matrix.go == '1.17' }} # Runs this on only one of the ci builds.
+        with:
+          green: 80
+          filename: coverage.out
+
+#      - name: Pull in remote changes
+#        run: git pull --rebase
+
+      - uses: stefanzweifel/git-auto-commit-action@v5
+        id: auto-commit-action
+        with:
+          commit_message: Apply Code Coverage Badge
+          skip_fetch: true
+          skip_checkout: true
+          file_pattern: ./README.md

README.md

@@ -1,4 +1,5 @@
 [![Go Reference](https://pkg.go.dev/badge/github.com/elastic/go-freelru.svg)](https://pkg.go.dev/github.com/elastic/go-freelru)
+![Coverage](https://img.shields.io/badge/Coverage-93.5%25-brightgreen)
 [![Go Report Card](https://goreportcard.com/badge/github.com/elastic/go-freelru)](https://goreportcard.com/report/github.com/elastic/go-freelru)
 
 # FreeLRU - A GC-less, fast and generic LRU hashmap library for Go