xo-alloc2 xo-gc: assorted utest-guided cleanup ++ coverage

utest/Role.test.cpp

@@ -0,0 +1,46 @@
+/** @file Role.test.cpp
+ *
+ *  @author Roland Conybeare, May 2026
+ **/
+
+#include "role.hpp"
+#include <catch2/catch.hpp>
+
+namespace xo {
+    using xo::mm::Role;
+
+    namespace ut {
+
+        TEST_CASE("Role-1", "[Role]")
+        {
+            /* 1. there are two distinct valid roles, 'to' and 'from',
+             * 2. valid roles fall in interval [begin, end)
+             */
+
+            REQUIRE(Role::to_space() == Role::to_space());
+            REQUIRE(Role::from_space() == Role::from_space());
+            REQUIRE(Role::to_space() != Role::from_space());
+
+            Role x0 = Role::begin();
+            {
+                bool ok = (x0 == Role::to_space() || x0 == Role::from_space());
+                REQUIRE(ok);
+            }
+            REQUIRE(x0 != Role::end());
+
+            Role x1 = x0.next();
+            REQUIRE(x1 != x0);
+            {
+                bool ok = (x1 == Role::to_space() || x1 == Role::from_space());
+                REQUIRE(ok);
+            }
+            REQUIRE(x1 != Role::end());
+
+            Role x2 = x1.next();
+            REQUIRE(x2 == Role::end());
+        }
+
+    }
+} /*namespace xo*/
+
+/* end Role.test.cpp */