add code coverage (#53)

* add code coverage

* use update comment

* add rpc for integ

.github/workflows/coverage.yml

@@ -0,0 +1,89 @@
+name: code coverage
+
+on: 
+  pull_request:
+    branches:
+    - main
+
+jobs:
+  comment-forge-coverage:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v3
+      with:
+        token: ${{ secrets.GITHUB_TOKEN }}
+
+    - name: Install foundry
+      uses: foundry-rs/foundry-toolchain@v1
+      with:
+          version: nightly
+    - name: Run Forge build
+      run: |
+          forge --version
+          forge build --sizes
+      id: build
+    - name: Run forge coverage
+      id: coverage
+      run: |
+        {
+        echo 'COVERAGE<<EOF'
+        forge coverage | grep -v 'test/' | tail -n +6
+        echo EOF
+        } >> "$GITHUB_OUTPUT"
+      env:
+        FOUNDRY_RPC_URL: '${{ secrets.RPC_URL }}'
+
+    - name: Check coverage is updated
+      uses: actions/github-script@v5
+      with:
+        github-token: ${{ secrets.GITHUB_TOKEN }}
+        script: |
+          const fs = require('fs');
+          const file = "coverage.txt"
+          if(!fs.existsSync(file)) {
+            console.log("Nothing to check");
+            return
+          }
+          const currentCoverage = fs.readFileSync(file, "utf8").trim();
+          const newCoverage = (`${{ steps.coverage.outputs.COVERAGE }}`).trim();
+          if (newCoverage != currentCoverage) {
+            core.setFailed(`Code coverage not updated. Run : forge coverage | grep -v 'test/' | tail -n +6  > coverage.txt`);
+          }
+
+    - name: Comment on PR
+      id: comment
+      uses: actions/github-script@v5
+      with:
+        github-token: ${{ secrets.GITHUB_TOKEN }}
+        script: |
+          const {data: comments} = await github.rest.issues.listComments({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: context.issue.number, 
+            })
+
+          const botComment = comments.find(comment => comment.user.id === 41898282)
+
+          const output = `${{ steps.coverage.outputs.COVERAGE }}`;
+          const commentBody = `Forge code coverage:\n${output}\n`;
+
+          if (botComment) {
+            github.rest.issues.updateComment({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              comment_id: botComment.id,
+              body: commentBody
+            })
+          } else {
+            github.rest.issues.createComment({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              body: commentBody
+            });
+          }