diff --git a/unit-tests/space_map_t.cc b/unit-tests/space_map_t.cc
index 1e002a1..daeef10 100644
--- a/unit-tests/space_map_t.cc
+++ b/unit-tests/space_map_t.cc
@@ -254,6 +254,15 @@ namespace {
 		test_set_affects_nr_allocated,
 		test_high_ref_counts
 	};
+
+	void
+	copy_space_maps(space_map::ptr lhs, space_map::ptr rhs) {
+		for (block_address b = 0; b < rhs->get_nr_blocks(); b++) {
+			uint32_t count = rhs->get_count(b);
+			if (count > 0)
+				lhs->set_count(b, rhs->get_count(b));
+		}
+	}
 }
 
 //----------------------------------------------------------------
@@ -285,4 +294,17 @@ TEST(SpaceMapTests, test_sm_metadata)
 	test_sm_reopen<sm_metadata_creator>();
 }
 
+TEST(SpaceMapTests, test_metadata_and_disk)
+{
+	block_manager<>::ptr bm(
+		new block_manager<>("./test.data", NR_BLOCKS, MAX_LOCKS, block_io<>::READ_WRITE));
+	space_map::ptr core_sm(new core_map(NR_BLOCKS));
+	transaction_manager::ptr tm(new transaction_manager(bm, core_sm));
+	persistent_space_map::ptr metadata_sm = persistent_data::create_metadata_sm(tm, NR_BLOCKS);
+	copy_space_maps(metadata_sm, core_sm);
+	tm->set_sm(metadata_sm);
+
+	persistent_space_map::ptr data_sm_ = create_disk_sm(tm, NR_BLOCKS * 2);
+}
+
 //----------------------------------------------------------------
diff --git a/unit-tests/thin_metadata_t.cc b/unit-tests/thin_metadata_t.cc
index a7c69b4..f28fb33 100644
--- a/unit-tests/thin_metadata_t.cc
+++ b/unit-tests/thin_metadata_t.cc
@@ -17,6 +17,7 @@ using namespace thin_provisioning;
 //----------------------------------------------------------------
 
 namespace {
+	// FIXME: duplication with block.tcc, factor out a file_utils unit
 	void rm_f(string path) {
 		struct stat info;
 		int r = ::stat(path.c_str(), &info);
@@ -37,7 +38,6 @@ namespace {
 		::unlink(path.c_str());
 	}
 
-	// FIXME: duplication with block.tcc, factor out a file_utils unit
 	void create_sized_file(string const &path, uint64_t file_size) {
 		int fd = ::open(path.c_str(), O_CREAT | O_TRUNC | O_RDWR, 0666);
 		if (fd < 0)
@@ -68,3 +68,5 @@ TEST(ThinMetadataTests, create)
 	create_sized_file(path, 4096 * 1024);
 	metadata::ptr md(new metadata(path, metadata::CREATE, 128, 102400));
 }
+
+//----------------------------------------------------------------