gha: collate and calculate coverage for all test runs

By combining the coverage from all platforms as well as privileged and
non-privileged Linux runs, the coverage is now 87.7% for the entire
project.

It was necessary to split the Windows CI scripts because mktemp doesn't
work in Powershell and it's necessary to reimplement the whole thing to
get what you need (not to mention that -test.gocoverdir needs to be
quoted in a particular way to not make Powershell angry).

Signed-off-by: Aleksa Sarai <[email protected]>

.github/workflows/ci.yml

@@ -11,14 +11,51 @@ on:
     - cron: "30 10 * * 0"
 
 jobs:
-  test:
+  test-windows:
+    strategy:
+      fail-fast: false
+      matrix:
+        go-version:
+          - "1.21"
+          - "1.22"
+          - "^1"
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-go@v4
+        with:
+          go-version: ${{ matrix.go-version }}
+      - name: mkdir gocoverdir
+        run: |
+          # mktemp --tmpdir -d gocoverdir.XXXXXXXX
+          function New-TemporaryDirectory {
+            param (
+              [string] $Prefix
+            )
+            $parent = [System.IO.Path]::GetTempPath()
+            do {
+              [string] $guid = [System.Guid]::NewGuid()
+              $item = New-Item -Path "$parent" -Name "$Prefix.$guid" -ItemType "directory" -ErrorAction SilentlyContinue
+            } while (-not "$item")
+            return $item.FullName
+          }
+          $GOCOVERDIR = (New-TemporaryDirectory -Prefix "gocoverdir")
+          echo "GOCOVERDIR=$GOCOVERDIR" >>"$env:GITHUB_ENV"
+      - name: unit tests
+        run: go test -v -cover '-test.gocoverdir' "$env:GOCOVERDIR" ./...
+      - name: upload coverage
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage-${{ runner.os }}-${{ github.job }}-${{ strategy.job-index }}
+          path: ${{ env.GOCOVERDIR }}
+
+  test-unix:
     strategy:
       fail-fast: false
       matrix:
         os:
           - ubuntu-latest
           - macos-latest
-          - windows-latest
         go-version:
           - "1.21"
           - "1.22"
@@ -33,9 +70,56 @@ jobs:
       - uses: actions/setup-go@v4
         with:
           go-version: ${{ matrix.go-version }}
+      - name: mkdir gocoverdir
+        run: |
+          GOCOVERDIR="$(mktemp --tmpdir -d gocoverdir.XXXXXXXX)"
+          echo "GOCOVERDIR=$GOCOVERDIR" >>"$GITHUB_ENV"
       - name: unit tests
-        run: go test -v -cover ./...
-      # TODO: Merge the code coverage stats from both runs...
-      - name: unit tests (root)
-        if: ${{ ! startsWith(matrix.os, 'windows-') }}
-        run: sudo go test -v -cover ./...
+        run: |
+          go test -v -cover -test.gocoverdir="$GOCOVERDIR" ./...
+          sudo go test -v -cover -test.gocoverdir="$GOCOVERDIR" ./...
+      - name: upload coverage
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage-${{ runner.os }}-${{ github.job }}-${{ strategy.job-index }}
+          path: ${{ env.GOCOVERDIR }}
+
+  coverage:
+    runs-on: ubuntu-latest
+    needs:
+      - test-windows
+      - test-unix
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-go@v4
+        with:
+          go-version: "^1"
+      - name: download all coverage
+        uses: actions/download-artifact@v4
+        with:
+          path: coverage
+      - name: generate coverage list
+        run: |
+          find coverage/
+          GOCOVERDIRS="$(printf '%s,' coverage/* | sed 's|,$||')"
+          echo "GOCOVERDIRS=$GOCOVERDIRS" >>"$GITHUB_ENV"
+          FULLCOVERAGE_FILE="$(mktemp --tmpdir fullcoverage.XXXXXXXX)"
+          echo "FULLCOVERAGE_FILE=$FULLCOVERAGE_FILE" >>"$GITHUB_ENV"
+      - name: compute coverage
+        run: go tool covdata percent -i "$GOCOVERDIRS"
+      - name: compute func coverage
+        run: go tool covdata func -i "$GOCOVERDIRS"
+      - name: merge coverage
+        run: |
+          go tool covdata textfmt -i "$GOCOVERDIRS" -o "$FULLCOVERAGE_FILE"
+          go tool cover -html="$FULLCOVERAGE_FILE" -o "$FULLCOVERAGE_FILE.html"
+      - name: upload merged coverage
+        uses: actions/upload-artifact@v4
+        with:
+          name: fullcoverage-${{ github.job }}
+          path: ${{ env.FULLCOVERAGE_FILE }}
+      - name: upload coverage html
+        uses: actions/upload-artifact@v4
+        with:
+          name: fullcoverage-${{ github.job }}.html
+          path: ${{ env.FULLCOVERAGE_FILE }}.html