diff --git a/tests/partition.c b/tests/partition.c
index 4688845..83df4ee 100644
--- a/tests/partition.c
+++ b/tests/partition.c
@@ -421,8 +421,12 @@ akerr_ErrorContext *test_reset_and_empty(char *name)
 	TEST_ASSERT(errctx, (rec.count == 0), "%s reported %d proxies in an empty world",
 		    name, rec.count);
 
-	CATCH(errctx, spawn(&world, &shape, 0.0f, 0.0f, &proxy));
+	// Build the shape before spawning from it, not after. Spawning first
+	// initializes the proxy from an uninitialized stack struct -- the sync
+	// below overwrites it, so the test still passed, and valgrind still
+	// reported eighteen uninitialised reads inside grid_cellrect.
 	CATCH(errctx, akgl_collision_shape_box(&shape, &body, 0.0f));
+	CATCH(errctx, spawn(&world, &shape, 0.0f, 0.0f, &proxy));
 	CATCH(errctx, akgl_collision_proxy_sync(proxy, &shape, 0.0f, 0.0f, 0.0f));
 	CATCH(errctx, world.partitioner.move(&world.partitioner, proxy));