chore: track code coverage in PRs

.github/workflows/tests.yaml

@@ -7,7 +7,8 @@ on:
   pull_request:
 
 permissions:
-  contents: read  #  to fetch code (actions/checkout)
+  pull-requests: write   # required for posting comments
+  contents: write        # required for git push
 
 jobs:
   build:
@@ -16,7 +17,19 @@ jobs:
     container: golang:latest
     steps:
     - uses: actions/checkout@v3
+    - name: Verify Changed files
+      id: verify-changed-files
+      uses: tj-actions/verify-changed-files@v20
+      with:
+        files: |
+          !*.md
     - name: Get dependencies
       run: go get -v -t -d ./...
     - name: Run tests
-      run: go test main_test.go main.go
+      run: go test -coverprofile=cover.out main_test.go main.go
+    - name: Install Vim
+      if: steps.verify-changed-files.outputs.files_changed == 'true'
+      run: apt-get update; apt-get install -y vim;
+    - name: Go Beautiful HTML Coverage
+      if: steps.verify-changed-files.outputs.files_changed == 'true'
+      uses: gha-common/go-beautiful-html-coverage@v1