diff --git a/test/mainnet_test.go b/test/mainnet_test.go
new file mode 100644
index 0000000..2966b35
--- /dev/null
+++ b/test/mainnet_test.go
@@ -0,0 +1,57 @@
+package test
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"net/http"
+	"strings"
+	"testing"
+)
+
+func getDataFromTheGraph() (map[string]map[string][]struct {
+	ID    string
+	Key   string
+	Value string
+}, error) {
+	res, err := http.Post("https://api.thegraph.com/subgraphs/name/ramilexe/blocknumstorage", "application/json", strings.NewReader(`
+		{
+			"query": "{\n  syncs(first: 5) {\n    id\n    key\n    value\n  }\n  storageSets(first: 5) {\n    id\n    key\n    value\n  }\n}\n",
+			"variables": null
+		}
+	`))
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+
+	jsonData, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	var data map[string]map[string][]struct {
+		ID    string
+		Key   string
+		Value string
+	}
+	if err := json.Unmarshal(jsonData, &data); err != nil {
+		return nil, err
+	}
+
+	return data, nil
+}
+
+func TestMainnet(t *testing.T) {
+	t.Log("Get data from api.thegraph.com")
+	theGraphData, err := getDataFromTheGraph()
+	if err != nil {
+		t.Fatalf("  error: %s", err)
+	}
+	if theGraphData == nil || theGraphData["data"] == nil {
+		t.Fatalf("  data must not be empty")
+	}
+	if theGraphData["data"]["storageSets"] == nil || theGraphData["data"]["syncs"] == nil {
+		t.Fatalf("  'storageSets' and 'syncs' must not be empty")
+	}
+	t.Log("  ok")
+}