Fix graph volume V()

test/graph_test.cc

@@ -45,13 +45,13 @@ TEST_SUITE("Graph") {
     CHECK_EQ(R, X);
   }
 
-  TEST_CASE("Digraph::V and Digraph::E") {
+  TEST_CASE("Graph::V and Graph::E") {
     // 1 --> 2 --> 3 --> 1
     //             3 --> 4 --> 5 --> 3
     //       2 --> 6 --> 7 --> 8 --> 6
     //             6 --> 9 --> 10 --> 11 --> 12 --> 13 --> 9
     //                                       12 --> 10
-    Digraph<std::uint16_t> G;
+    Graph<std::uint16_t> G;
     G.insert(1, 2);
     G.insert(2, 3);
     G.insert(3, 1);