From 807f2da166fd5d0a13e76418b4b91838a4ac5ef8 Mon Sep 17 00:00:00 2001
From: lixueclaire <youli.lx@alibaba-inc.com>
Date: Sat, 6 May 2023 20:22:43 +0800
Subject: [PATCH] Implement the add-assign operator for VertexIter (#151)

---
 cpp/include/gar/graph.h |  6 ++++++
 cpp/test/test_graph.cc  | 11 +++++++++++
 2 files changed, 17 insertions(+)

diff --git a/cpp/include/gar/graph.h b/cpp/include/gar/graph.h
index ac3760192..965d75f23 100644
--- a/cpp/include/gar/graph.h
+++ b/cpp/include/gar/graph.h
@@ -213,6 +213,12 @@ class VertexIter {
     return ret;
   }
 
+  /** The add-assign operator. */
+  VertexIter& operator+=(IdType offset) {
+    cur_offset_ += offset;
+    return *this;
+  }
+
   /** The equality operator. */
   bool operator==(const VertexIter& rhs) const noexcept {
     return cur_offset_ == rhs.cur_offset_;
diff --git a/cpp/test/test_graph.cc b/cpp/test/test_graph.cc
index 55832c810..2bfa172e8 100644
--- a/cpp/test/test_graph.cc
+++ b/cpp/test/test_graph.cc
@@ -56,6 +56,17 @@ TEST_CASE("test_vertices_collection") {
             << ", id=" << it_last.property<int64_t>("id").value()
             << ", firstName="
             << it_last.property<std::string>("firstName").value() << std::endl;
+  auto it_begin = it_last + (1 - count);
+
+  auto it = vertices.begin();
+  it += (count - 1);
+  REQUIRE(it.id() == it_last.id());
+  REQUIRE(it.property<int64_t>("id").value() ==
+          it_last.property<int64_t>("id").value());
+  it += (1 - count);
+  REQUIRE(it.id() == it_begin.id());
+  REQUIRE(it.property<int64_t>("id").value() ==
+          it_begin.property<int64_t>("id").value());
 }
 
 TEST_CASE("test_edges_collection", "[Slow]") {