Add arbotree interface wrapper

treeinterface/arbotree/wrapper_test.go

@@ -0,0 +1,22 @@
+package arbotree
+
+import (
+	"testing"
+
+	"go.vocdoni.io/dvote/censustree"
+)
+
+func TestInterface(t *testing.T) {
+	storage := t.TempDir()
+	tree := &Tree{}
+	err := tree.Init("test", storage)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	var i interface{} = tree
+	_, ok := i.(censustree.Tree)
+	if !ok {
+		t.Fatal("censustree interface not matched by arbotree wrapper")
+	}
+}