Revert "Try without cover"

This reverts commit e91b1e8.

.github/workflows/go-test.yml

@@ -40,8 +40,10 @@ jobs:
       - name: Run tests
         uses: protocol/multiple-go-modules@v1.2
         with:
-          # I know this is autogenerated, I'm running an experiment
-          run: go test -v -shuffle=on ./...
+          # Use -coverpkg=./..., so that we include cross-package coverage.
+          # If package ./A imports ./B, and ./A's tests also cover ./B,
+          # this means ./B's coverage will be significantly higher than 0%.
+          run: go test -v -shuffle=on -coverprofile=module-coverage.txt -coverpkg=./... ./...
       - name: Run tests (32 bit)
         if: ${{ matrix.os != 'macos' }} # can't run 32 bit tests on OSX.
         uses: protocol/multiple-go-modules@v1.2
@@ -56,3 +58,11 @@ jobs:
         uses: protocol/multiple-go-modules@v1.2
         with:
           run: go test -v -race ./...
+      - name: Collect coverage files
+        shell: bash
+        run: echo "COVERAGES=$(find . -type f -name 'module-coverage.txt' | tr -s '\n' ',' | sed 's/,$//')" >> $GITHUB_ENV
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@81cd2dc8148241f03f5839d295e000b8f761e378 # v3.1.0
+        with:
+          files: '${{ env.COVERAGES }}'
+          env_vars: OS=${{ matrix.os }}, GO=${{ matrix.go }}