Improve tests, add two methods to ElementCollection

Author: d-kad

src/games/game.h

@@ -62,7 +62,6 @@ template <class P, class T> class ElementCollection {
 
 public:
   class iterator {
-    friend class GameRep;
 
     P m_owner{nullptr};
     const std::vector<T *> *m_container{nullptr};
@@ -106,6 +105,7 @@ template <class P, class T> class ElementCollection {
       return *this;
     }
     value_type operator*() const { return m_container->at(m_index); }
+    P GetOwner() const { return m_owner; }
   };
 
   ElementCollection() = default;
@@ -121,6 +121,8 @@ template <class P, class T> class ElementCollection {
   {
     return m_owner == p_other.m_owner && m_container == p_other.m_container;
   }
+
+  bool empty() const { return size() == 0; }
   size_t size() const { return m_container->size(); }
   GameObjectPtr<T> front() const { return m_container->front(); }
   GameObjectPtr<T> back() const { return m_container->back(); }
@@ -566,7 +568,7 @@ class GameRep : public BaseGameRep {
 
         while (!m_stack.empty()) {
           auto &top_it = m_stack.top();
-          auto end_it = top_it.m_owner->GetChildren().end();
+          auto end_it = top_it.GetOwner()->GetChildren().end();
           if (top_it != end_it) {
             m_current_node = *top_it;
             ++top_it;

tests/test_node.py

@@ -803,15 +803,11 @@ def test_node_plays():
     ],
 )
 def test_nodes_iteration_order(game_obj: gbt.Game):
-    """
-    Verify that the C++ `game.nodes` iterator produces the DFS traversal.
-
+    """Verify that the C++ `game.nodes` iterator produces the DFS traversal.
     """
     def dfs(node: gbt.Node) -> typing.Iterator[gbt.Node]:
         yield node
         for child in node.children:
             yield from dfs(child)
 
-    zipped_nodes = itertools.zip_longest(game_obj.nodes, dfs(game_obj.root))
-
-    assert all(a == b for a, b in zipped_nodes)
+    assert all(a == b for a, b in itertools.zip_longest(game_obj.nodes, dfs(game_obj.root)))