From 93810790ae6f5336902a07675a0537a726e66739 Mon Sep 17 00:00:00 2001
From: Gene Harvey <gharveymn@gmail.com>
Date: Sat, 30 Nov 2024 17:42:26 -0600
Subject: [PATCH] Add verification of proper usage of
 `select_on_container_copy_construction` to unit tests

---
 source/test/test_allocators.hpp               | 99 ++++++++++++++++++-
 source/test/unit/member/assign/test-copy.cpp  |  4 +
 source/test/unit/member/assign/test-move.cpp  |  4 +
 .../unit/member/constructor/test-copy.cpp     |  2 +
 .../unit/member/constructor/test-move.cpp     |  2 +
 5 files changed, 110 insertions(+), 1 deletion(-)

diff --git a/source/test/test_allocators.hpp b/source/test/test_allocators.hpp
index b9a6dfb..6ae3fe3 100644
--- a/source/test/test_allocators.hpp
+++ b/source/test/test_allocators.hpp
@@ -399,7 +399,8 @@ namespace gch
       template <typename U>
       constexpr GCH_IMPLICIT_CONVERSION
       verifying_allocator (const verifying_allocator<U, PartialTraits>& other) noexcept
-        : base (other)
+        : base (other),
+          created_by_container_copy_construction (other.created_by_container_copy_construction)
       { }
 
       GCH_NODISCARD
@@ -452,8 +453,44 @@ namespace gch
         remove_object (p);
         alloc_traits::destroy (*this, p);
       }
+
+      verifying_allocator
+      select_on_container_copy_construction () const
+      {
+        verifying_allocator ret (*this);
+        ret.created_by_container_copy_construction = true;
+        return ret;
+      }
+
+      bool created_by_container_copy_construction = false;
     };
 
+    template <typename A>
+    constexpr void
+    verify_created_by_container_copy_construction (const A& a)
+    { }
+
+    template <typename T, typename Traits>
+    constexpr void
+    verify_created_by_container_copy_construction (const verifying_allocator<T, Traits>& a)
+    {
+      assert (a.created_by_container_copy_construction
+          &&  "select_on_container_copy_construction unexpectedly invoked");
+    }
+
+    template <typename A>
+    constexpr void
+    verify_not_created_by_container_copy_construction (const A& a)
+    { }
+
+    template <typename T, typename Traits>
+    constexpr void
+    verify_not_created_by_container_copy_construction (const verifying_allocator<T, Traits>& a)
+    {
+      assert (! a.created_by_container_copy_construction
+            &&  "select_on_container_copy_construction unexpectedly not invoked");
+    }
+
     template <typename T, typename Traits>
     constexpr
     bool
@@ -489,6 +526,12 @@ namespace gch
       using propagate_on_container_move_assignment = std::false_type;
       using propagate_on_container_copy_assignment = std::false_type;
       using propagate_on_container_swap = std::false_type;
+
+      non_propagating_verifying_allocator
+      select_on_container_copy_construction () const
+      {
+        return non_propagating_verifying_allocator {};
+      }
     };
 
     template <typename T, typename Traits>
@@ -604,6 +647,60 @@ namespace gch
       return ! (lhs == rhs);
     }
 
+    template <typename Allocator>
+    class allocator_testing_traits
+    {
+      template <typename, typename = void>
+      struct has_created_by_container_copy_construction_field
+        : std::false_type
+      { };
+
+      template <typename A>
+      struct has_created_by_container_copy_construction_field<A,
+            decltype((void) A::created_by_container_copy_construction, void ())>
+        : std::true_type
+      { };
+
+    public:
+      template <typename A = Allocator,
+        typename std::enable_if<
+          has_created_by_container_copy_construction_field<A>::value
+        >::type * = nullptr>
+      constexpr void
+      verify_created_by_container_copy_construction (const A& a)
+      {
+        assert (a.created_by_container_copy_construction
+                &&  "select_on_container_copy_construction unexpectedly not invoked");
+      }
+
+      template <typename A = Allocator,
+        typename std::enable_if<
+          ! has_created_by_container_copy_construction_field<A>::value
+        >::type * = nullptr>
+      constexpr void
+      verify_created_by_container_copy_construction (const A&)
+      { }
+
+      template <typename A = Allocator,
+        typename std::enable_if<
+          has_created_by_container_copy_construction_field<A>::value
+        >::type * = nullptr>
+      constexpr void
+      verify_not_created_by_container_copy_construction (const A& a)
+      {
+        assert (! a.created_by_container_copy_construction
+                &&  "select_on_container_copy_construction unexpectedly not invoked");
+      }
+
+      template <typename A = Allocator,
+        typename std::enable_if<
+          ! has_created_by_container_copy_construction_field<A>::value
+        >::type * = nullptr>
+      constexpr void
+      verify_not_created_by_container_copy_construction (const A&)
+      { }
+    };
+
   }
 
 }
diff --git a/source/test/unit/member/assign/test-copy.cpp b/source/test/unit/member/assign/test-copy.cpp
index 98eb044..a3643be 100644
--- a/source/test/unit/member/assign/test-copy.cpp
+++ b/source/test/unit/member/assign/test-copy.cpp
@@ -211,6 +211,7 @@ struct tester
 
       n.assign (m);
       CHECK (n == m_cmp);
+      gch::test_types::verify_not_created_by_container_copy_construction (n.get_allocator ());
     }
     {
       // vector_type<N> (ni) -> vector_type<M> (mi)
@@ -222,6 +223,7 @@ struct tester
 
       m.assign (n);
       CHECK (m == n_cmp);
+      gch::test_types::verify_not_created_by_container_copy_construction (m.get_allocator ());
     }
     {
       // vector_type<M> (ni) -> vector_type<N> (mi)
@@ -233,6 +235,7 @@ struct tester
 
       n.assign (m);
       CHECK (n == n_cmp);
+      gch::test_types::verify_not_created_by_container_copy_construction (n.get_allocator ());
     }
     {
       // vector_type<N> (mi) -> vector_type<M> (ni)
@@ -244,6 +247,7 @@ struct tester
 
       m.assign (n);
       CHECK (m == m_cmp);
+      gch::test_types::verify_not_created_by_container_copy_construction (m.get_allocator ());
     }
   }
 
diff --git a/source/test/unit/member/assign/test-move.cpp b/source/test/unit/member/assign/test-move.cpp
index b5bca52..8b41ee8 100644
--- a/source/test/unit/member/assign/test-move.cpp
+++ b/source/test/unit/member/assign/test-move.cpp
@@ -318,6 +318,7 @@ struct tester
 
       n.assign (std::move (m));
       CHECK (n == m_cmp);
+      gch::test_types::verify_not_created_by_container_copy_construction (n.get_allocator ());
     }
     {
       // vector_type<N> (ni) -> vector_type<M> (mi)
@@ -329,6 +330,7 @@ struct tester
 
       m.assign (std::move (n));
       CHECK (m == n_cmp);
+      gch::test_types::verify_not_created_by_container_copy_construction (m.get_allocator ());
     }
     {
       // vector_type<M> (ni) -> vector_type<N> (mi)
@@ -340,6 +342,7 @@ struct tester
 
       n.assign (std::move (m));
       CHECK (n == n_cmp);
+      gch::test_types::verify_not_created_by_container_copy_construction (n.get_allocator ());
     }
     {
       // vector_type<N> (mi) -> vector_type<M> (ni)
@@ -351,6 +354,7 @@ struct tester
 
       m.assign (std::move (n));
       CHECK (m == m_cmp);
+      gch::test_types::verify_not_created_by_container_copy_construction (m.get_allocator ());
     }
   }
 
diff --git a/source/test/unit/member/constructor/test-copy.cpp b/source/test/unit/member/constructor/test-copy.cpp
index 9955189..bfd971a 100644
--- a/source/test/unit/member/constructor/test-copy.cpp
+++ b/source/test/unit/member/constructor/test-copy.cpp
@@ -118,6 +118,7 @@ struct tester
 
       vector_type<N> v (m);
       CHECK (v == m_cmp);
+      gch::test_types::verify_created_by_container_copy_construction (v.get_allocator ());
     }
     {
       vector_type<M> m (mi.begin (), mi.end (), m_alloc);
@@ -125,6 +126,7 @@ struct tester
 
       vector_type<N> v (m, m_alloc);
       CHECK (v == m_cmp);
+      gch::test_types::verify_not_created_by_container_copy_construction (v.get_allocator ());
     }
   }
 
diff --git a/source/test/unit/member/constructor/test-move.cpp b/source/test/unit/member/constructor/test-move.cpp
index 621a520..7c2bb4f 100644
--- a/source/test/unit/member/constructor/test-move.cpp
+++ b/source/test/unit/member/constructor/test-move.cpp
@@ -119,6 +119,7 @@ struct tester
 
       vector_type<N> v (std::move (m));
       CHECK (v == m_cmp);
+      gch::test_types::verify_not_created_by_container_copy_construction (v.get_allocator ());
     }
     {
       vector_type<M> m (mi.begin (), mi.end (), m_alloc);
@@ -126,6 +127,7 @@ struct tester
 
       vector_type<N> v (std::move (m), m_init_alloc);
       CHECK (v == m_cmp);
+      gch::test_types::verify_not_created_by_container_copy_construction (v.get_allocator ());
     }
   }