feat: add script to generate JaCoCo coverage badge and update workflow to commit badge on push

Author: brunoborges

.github/scripts/generate-coverage-badge.sh

@@ -0,0 +1,64 @@
+#!/usr/bin/env bash
+# Generates an SVG coverage badge from a JaCoCo CSV report.
+#
+# Usage: generate-coverage-badge.sh [jacoco.csv] [output-dir]
+#   jacoco.csv  - Path to JaCoCo CSV report (default: target/site/jacoco-coverage/jacoco.csv)
+#   output-dir  - Directory for the badge SVG (default: .github/badges)
+set -euo pipefail
+
+CSV="${1:-target/site/jacoco-coverage/jacoco.csv}"
+BADGES_DIR="${2:-.github/badges}"
+
+if [ ! -f "$CSV" ]; then
+  echo "⚠️ No JaCoCo CSV report found at $CSV"
+  exit 0
+fi
+
+# Sum INSTRUCTION_MISSED and INSTRUCTION_COVERED across all rows (skip header)
+read -r missed covered <<< "$(awk -F',' 'NR>1 { m+=$4; c+=$5 } END { print m, c }' "$CSV")"
+total=$((missed + covered))
+if [ "$total" -eq 0 ]; then
+  pct="0"
+else
+  pct=$(awk "BEGIN { printf \"%.1f\", ($covered / $total) * 100 }")
+  # Drop trailing .0
+  pct=$(echo "$pct" | sed 's/\.0$//')
+fi
+echo "Coverage: ${pct}%"
+
+# Choose badge color based on coverage
+color="#e05d44"  # red <60
+if   awk "BEGIN{exit!($pct>=100)}"; then color="#4c1"     # bright green
+elif awk "BEGIN{exit!($pct>=90)}";  then color="#97ca00"  # green
+elif awk "BEGIN{exit!($pct>=80)}";  then color="#a4a61d"  # yellow-green
+elif awk "BEGIN{exit!($pct>=70)}";  then color="#dfb317"  # yellow
+elif awk "BEGIN{exit!($pct>=60)}";  then color="#fe7d37"  # orange
+fi
+
+# Generate SVG badge
+mkdir -p "$BADGES_DIR"
+label="coverage"
+value="${pct}%"
+lw=62; vw=46; tw=$((lw + vw))
+cat > "${BADGES_DIR}/jacoco.svg" <<EOF
+<svg xmlns="http://www.w3.org/2000/svg" width="${tw}" height="20">
+  <linearGradient id="b" x2="0" y2="100%">
+    <stop offset="0" stop-color="#bbb" stop-opacity=".1"/>
+    <stop offset="1" stop-opacity=".1"/>
+  </linearGradient>
+  <mask id="a"><rect width="${tw}" height="20" rx="3" fill="#fff"/></mask>
+  <g mask="url(#a)">
+    <rect width="${lw}" height="20" fill="#555"/>
+    <rect x="${lw}" width="${vw}" height="20" fill="${color}"/>
+    <rect width="${tw}" height="20" fill="url(#b)"/>
+  </g>
+  <g fill="#fff" text-anchor="middle" font-family="DejaVu Sans,Verdana,Geneva,sans-serif" font-size="11">
+    <text x="$((lw/2))" y="15" fill="#010101" fill-opacity=".3">${label}</text>
+    <text x="$((lw/2))" y="14">${label}</text>
+    <text x="$((lw + vw/2))" y="15" fill="#010101" fill-opacity=".3">${value}</text>
+    <text x="$((lw + vw/2))" y="14">${value}</text>
+  </g>
+</svg>
+EOF
+
+echo "Badge generated at ${BADGES_DIR}/jacoco.svg"

.github/workflows/build-test.yml

@@ -19,7 +19,7 @@ on:
   merge_group:
 
 permissions:
-  contents: read
+  contents: write
   checks: write
 
 jobs:
@@ -86,6 +86,20 @@ jobs:
             target/surefire-reports/
           retention-days: 1
 
+      - name: Generate and commit JaCoCo badge
+        if: success() && github.event_name == 'push' && github.ref == 'refs/heads/main'
+        run: |
+          .github/scripts/generate-coverage-badge.sh
+
+          # Commit if changed
+          if [[ $(git status --porcelain .github/badges/) ]]; then
+            git config --global user.name 'github-actions[bot]'
+            git config --global user.email '41898282+github-actions[bot]@users.noreply.github.com'
+            git add .github/badges/
+            git commit -m "Update JaCoCo coverage badge"
+            git push
+          fi
+
       - name: Generate Test Report Summary
         if: always()
         uses: ./.github/actions/test-report

README.md

@@ -2,6 +2,7 @@
 
 [![Build](https://github.com/copilot-community-sdk/copilot-sdk-java/actions/workflows/build-test.yml/badge.svg)](https://github.com/copilot-community-sdk/copilot-sdk-java/actions/workflows/build-test.yml)
 [![Site](https://github.com/copilot-community-sdk/copilot-sdk-java/actions/workflows/deploy-site.yml/badge.svg)](https://github.com/copilot-community-sdk/copilot-sdk-java/actions/workflows/deploy-site.yml)
+[![Coverage](.github/badges/jacoco.svg)](https://copilot-community-sdk.github.io/copilot-sdk-java/snapshot/jacoco/index.html)
 [![Documentation](https://img.shields.io/badge/docs-online-brightgreen)](https://copilot-community-sdk.github.io/copilot-sdk-java/)
 [![Java 17+](https://img.shields.io/badge/Java-17%2B-blue)](https://openjdk.org/)
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)