diff --git a/include/xo/gc/X1CollectorConfig.hpp b/include/xo/gc/X1CollectorConfig.hpp
index 5bbc377..4b889ef 100644
--- a/include/xo/gc/X1CollectorConfig.hpp
+++ b/include/xo/gc/X1CollectorConfig.hpp
@@ -8,7 +8,6 @@
 #include "GCObjectStoreConfig.hpp"
 #include "MutationLogConfig.hpp"
 #include "object_age.hpp"
-//#include "Generation.hpp"
 #include <xo/arena/ArenaConfig.hpp>
 #include <array>
 #include <cstdint>
diff --git a/utest/CMakeLists.txt b/utest/CMakeLists.txt
index 0f3c967..5ffcac8 100644
--- a/utest/CMakeLists.txt
+++ b/utest/CMakeLists.txt
@@ -7,6 +7,7 @@ set(UTEST_SRCS
     Collector.test.cpp
     X1Collector.test.cpp
     DX1CollectorIterator.test.cpp
+    GCObjectStore.test.cpp
     Object2.test.cpp
     random_allocs.cpp
 )
diff --git a/utest/GCObjectStore.test.cpp b/utest/GCObjectStore.test.cpp
new file mode 100644
index 0000000..399a7ae
--- /dev/null
+++ b/utest/GCObjectStore.test.cpp
@@ -0,0 +1,94 @@
+/** @file GCObjectStore.test.cpp
+ *
+ *  @author Roland Conybeare, Apr 2026
+ **/
+
+#include <xo/object2/List.hpp>
+#include <xo/object2/Integer.hpp>
+#include <xo/gc/GCObjectStore.hpp>
+#include <xo/alloc2/GCObject.hpp>
+#include <xo/indentlog/scope.hpp>
+#include <catch2/catch.hpp>
+
+namespace ut {
+    using xo::scm::DList;
+    using xo::scm::DInteger;
+    using xo::mm::GCObjectStoreConfig;
+    using xo::mm::GCObjectStore;
+    using xo::mm::AGCObject;
+    using xo::mm::ArenaConfig;
+    using xo::facet::typeseq;
+    using xo::facet::impl_for;
+    using xo::scope;
+    using std::size_t;
+    using std::uint32_t;
+
+    namespace {
+        struct Testcase {
+            explicit Testcase(uint32_t n_gen, uint32_t n_survive,
+                              size_t gc_z, uint32_t type_z)
+                : n_gen_{n_gen},
+                  n_survive_{n_survive},
+                  gc_size_{gc_z},
+                  object_type_z_{type_z}
+                {}
+
+            /** number of generations in gco store **/
+            uint32_t n_gen_ = 0;
+            /** object promotes on surviving this many gc cycles **/
+            uint32_t n_survive_ = 0;
+            /** size of each generation's half-space, in bytes **/
+            size_t gc_size_ = 0;
+            /** Storage for object type array, in bytes.
+             *  (need to allow 1 pointer per type)
+             **/
+            uint32_t object_type_z_ = 0;
+
+        };
+
+        static std::vector<Testcase> s_testcase_v = {
+            /** n_gen, n_survive, gc_size, object_type_z **/
+            Testcase(2, 4, 16 * 1024, 8 * 128),
+        };
+    }
+
+    TEST_CASE("GCObjectStore-1", "[GCObjectStore]")
+    {
+        constexpr bool c_debug_flag = false;
+        scope log(XO_DEBUG(c_debug_flag));
+
+        for (size_t i_tc = 0, n_tc = s_testcase_v.size(); i_tc < n_tc; ++i_tc) {
+            const Testcase & tc = s_testcase_v[i_tc];
+
+            /** config for each half-space **/
+            ArenaConfig arena_config
+                = (ArenaConfig()
+                   .with_name("arena-name-not-used")
+                   .with_size(tc.gc_size_)
+                   .with_store_header_flag(true));
+
+            GCObjectStoreConfig gcos_config(arena_config,
+                                            tc.n_gen_,
+                                            tc.n_survive_,
+                                            tc.object_type_z_,
+                                            c_debug_flag);
+
+            // object type storage will be empty unless we install a type.
+            GCObjectStore gcos(gcos_config);
+
+            REQUIRE(gcos.is_type_installed(typeseq::id<DList>()) == false);
+
+            //REQUIRE(nullptr == gcos.lookup_type(typeseq::id<DList>()));
+
+#ifdef NOT_YET
+
+
+//            // Usual path would be via ACollector interface; that's inconvenient here
+//
+#endif
+        }
+    }
+
+} /*namespace ut*/
+
+/* end GCObjectStore.test.cpp */
diff --git a/utest/Object2.test.cpp b/utest/Object2.test.cpp
index fa0baec..4bda353 100644
--- a/utest/Object2.test.cpp
+++ b/utest/Object2.test.cpp
@@ -63,7 +63,7 @@ namespace ut {
 
     TEST_CASE("printable1", "[pp][x1][list]")
     {
-        constexpr bool c_debug_flag = true;
+        constexpr bool c_debug_flag = false;
         scope log(XO_DEBUG(c_debug_flag));
 
         bool ok = SetupObject2::register_facets();
diff --git a/utest/X1Collector.test.cpp b/utest/X1Collector.test.cpp
index bfea2eb..04e5c45 100644
--- a/utest/X1Collector.test.cpp
+++ b/utest/X1Collector.test.cpp
@@ -11,13 +11,13 @@
 #include "DArray.hpp"
 
 #include <xo/object2/Float.hpp>
-//#include "number/IGCObject_DFloat.hpp"
-#include "number/IGCObject_DInteger.hpp"
-#include "list/IGCObject_DList.hpp"
+#include <xo/object2/Integer.hpp>
+#include <xo/object2/List.hpp>
+//#include "list/IGCObject_DList.hpp"
 
-#include <xo/alloc2/CollectorTypeRegistry.hpp>
-#include <xo/alloc2/Collector.hpp>
 #include <xo/gc/X1Collector.hpp>
+//#include <xo/alloc2/Collector.hpp>
+#include <xo/alloc2/CollectorTypeRegistry.hpp>
 
 #include <xo/arena/AllocInfo.hpp>
 #include <xo/arena/padding.hpp>
diff --git a/utest/gc_utest_main.cpp b/utest/gc_utest_main.cpp
index 8c42600..cb1a31f 100644
--- a/utest/gc_utest_main.cpp
+++ b/utest/gc_utest_main.cpp
@@ -1,6 +1,32 @@
 /* file gc_utest_main.cpp */
 
-#define CATCH_CONFIG_MAIN
-#include "catch2/catch.hpp"
+#include <xo/gc/init_gc.hpp>
+#include <xo/subsys/Subsystem.hpp>
+
+#define CATCH_CONFIG_RUNNER
+#include <catch2/catch.hpp>
+
+using xo::S_gc_tag;
+using xo::InitSubsys;
+using xo::InitEvidence;
+
+// ensure xo-gc properly initialized when Subsystem::initialize_all() runs
+static InitEvidence s_init = (InitSubsys<S_gc_tag>::require());
+
+int
+main(int argc, char* argv[])
+{
+    using xo::Subsystem;
+
+    // Your custom initialization code here
+    Subsystem::initialize_all();
+
+    // Run Catch2's test session
+    int result = Catch::Session().run(argc, argv);
+
+    // cleanup here, if any
+
+    return result;
+}
 
 /* end gc_utest_main.cpp */