Update CI to run tests with coverage collection

We updated the way we collect the test coverage, so the CI workflow
should reflect this as well.

.github/workflows/qa.yaml

@@ -90,17 +90,33 @@ jobs:
         run: |
           set -eu
           cargo install grcov
-      - name: Run tests
+      - name: Run tests (with coverage collection)
         run: |
           set -eu
 
-          go test -coverpkg=./... -coverprofile=/tmp/coverage.out -covermode=set ./... -shuffle=on
+          # The coverage is not written if the output directory does not exist, so we need to create it.
+          raw_cov_dir="/tmp/raw_files"
+          rm -fr "${raw_cov_dir}"
+          mkdir -p "${raw_cov_dir}"
+
+          # Overriding the default coverage directory is not an exported flag of go test (yet), so
+          # we need to override it using the test.gocoverdir flag instead.
+          #TODO: Update when https://go-review.googlesource.com/c/go/+/456595 is merged.
+          go test -cover -covermode=set ./... -shuffle=on -args -test.gocoverdir="${raw_cov_dir}"
+
+          # Convert the raw coverage data into textfmt so we can merge the Rust one into it
+          go tool covdata textfmt -i="${raw_cov_dir}" -o="/tmp/coverage.out"
+
+          # Append the Rust coverage data to the Go one
+          cat "${raw_cov_dir}/rust-cov/rust2go_coverage" >>"/tmp/coverage.out"
+
+          # Filter out the testutils package and the pb.go file
+          grep -v -e "testutils" -e "pb.go" "/tmp/coverage.out" >"/tmp/coverage.out.filtered"
+
       - name: Run tests (with race detector)
         run: |
           go test -race ./...
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@v3
         with:
-          file: /tmp/coverage.combined
-
-  # TODO: rust-tests:
+          file: /tmp/coverage.out.filtered