Use more permissive checks in release

Compilers are allowed and able to optimise heap allocations, even if it means this has an observable effect when using a custom operator new(). This is true since C++17 and N3664.

Author: cschreib

tests/runtime_tests_make_observable.cpp

@@ -10,9 +10,9 @@ TEMPLATE_LIST_TEST_CASE("make observable", "[make_observable][owner]", owner_typ
             TestType ptr = oup::make_observable<get_object<TestType>, get_policy<TestType>>();
 
             if constexpr (is_sealed<TestType>) {
-                CHECK(mem_track.allocated() == 1u);
+                CHECK_MAX_ALLOC(1u);
             } else {
-                CHECK(mem_track.allocated() == 2u);
+                CHECK_MAX_ALLOC(2u);
             }
             CHECK(ptr.get() != nullptr);
             CHECK(ptr->state_ == test_object::state::default_init);
@@ -35,9 +35,9 @@ TEMPLATE_LIST_TEST_CASE("make observable with arguments", "[make_observable][own
                 test_object::state::special_init);
 
             if constexpr (is_sealed<TestType>) {
-                CHECK(mem_track.allocated() == 1u);
+                CHECK_MAX_ALLOC(1u);
             } else {
-                CHECK(mem_track.allocated() == 2u);
+                CHECK_MAX_ALLOC(2u);
             }
             CHECK(ptr.get() != nullptr);
             CHECK(ptr->state_ == test_object::state::special_init);
@@ -84,7 +84,7 @@ TEST_CASE("make observable unique", "[make_observable][owner]") {
     {
         TestType ptr = oup::make_observable_unique<test_object>();
 
-        CHECK(mem_track.allocated() == 2u);
+        CHECK_MAX_ALLOC(2u);
         CHECK(ptr.get() != nullptr);
         CHECK(ptr->state_ == test_object::state::default_init);
         CHECK_INSTANCES(1, 1);
@@ -100,7 +100,7 @@ TEST_CASE("make observable sealed", "[make_observable][owner]") {
     {
         TestType ptr = oup::make_observable_sealed<test_object>();
 
-        CHECK(mem_track.allocated() == 1u);
+        CHECK_MAX_ALLOC(1u);
         CHECK(ptr.get() != nullptr);
         CHECK(ptr->state_ == test_object::state::default_init);
         CHECK_INSTANCES(1, 1);

tests/tests_common.hpp

@@ -630,6 +630,16 @@ using owner_types = snatch::type_list<
         CHECK(mem_track.double_delete() == 0u);                                                    \
     } while (0)
 
+#if defined(NDEBUG)
+// When not in debug (hence, assuming optimisations are turned on),
+// some compilers manage to optimise-out some heap allocations, so use a looser
+// check.
+#    define CHECK_MAX_ALLOC(MAX_ALLOC) CHECK(mem_track.allocated() <= MAX_ALLOC)
+#else
+// In debug, allocations must be exactly as expected.
+#    define CHECK_MAX_ALLOC(MAX_ALLOC) CHECK(mem_track.allocated() == MAX_ALLOC)
+#endif
+
 // clang-format off
 #if defined(__clang__)
 #    define SNATCH_WARNING_DISABLE_SELF_ASSIGN _Pragma("clang diagnostic ignored \"-Wself-assign-overloaded\"")