diff --git a/state/service_test.go b/state/service_test.go
new file mode 100644
index 0000000..2c089ad
--- /dev/null
+++ b/state/service_test.go
@@ -0,0 +1,28 @@
+package state
+
+import (
+	"encoding/json"
+	"expvar"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestEncodeVariables(t *testing.T) {
+	dump := make(map[string]interface{})
+
+	expvar.NewString("test1").Set("test1")
+	expvar.NewString("test2").Set("test2")
+
+	res := EncodeVariables()
+
+	require.NoError(t, json.Unmarshal(res.Variables, &dump))
+	require.NotEmpty(t, dump)
+
+	// dump should contains keys `test1` and `test2`
+	require.Contains(t, dump, "test1")
+	require.Equal(t, "test1", dump["test1"])
+
+	require.Contains(t, dump, "test2")
+	require.Equal(t, "test2", dump["test2"])
+}