diff --git a/.github/workflows/go.yml b/.github/workflows/go.yml
index b3e6746..59863e7 100644
--- a/.github/workflows/go.yml
+++ b/.github/workflows/go.yml
@@ -16,9 +16,10 @@ jobs:
       uses: actions/setup-go@v2
       with:
         go-version: 1.16
-
-    - name: Build
-      run: go build -v ./...
-
     - name: Test
-      run: go test -v ./...
\ No newline at end of file
+      run: go test -race -coverprofile="coverage.txt" -covermode=atomic ./...
+
+    - name: upload coverage
+      uses: codecov/codecov-action@v1
+      with:
+        token: ${{ secrets.CODECOV_TOKEN }}
diff --git a/utils.go b/utils.go
index c061020..520157b 100644
--- a/utils.go
+++ b/utils.go
@@ -62,7 +62,10 @@ func GetRRSetOrCreate(n NameNodeInterface, rrtype uint16, ttl uint32) RRSetInter
 
 func GetRDATA(rr dns.RR) string {
 	v := strings.SplitN(rr.String(), "\t", 5)
-	return v[5]
+	if len(v) != 5 {
+		return "<nil>"
+	}
+	return v[4]
 }
 
 func MakeRR(r RRSetInterface, rdata string) (dns.RR, error) {