diff --git a/codex/slotbuilder/slotbuilder.nim b/codex/slotbuilder/slotbuilder.nim
new file mode 100644
index 00000000..21ef9024
--- /dev/null
+++ b/codex/slotbuilder/slotbuilder.nim
@@ -0,0 +1,6 @@
+
+type
+  SlotBuilder* = object of RootObj
+
+proc aaa*(self: SlotBuilder): void =
+  echo "aaa"
diff --git a/tests/codex/slotbuilder/testslotbuilder.nim b/tests/codex/slotbuilder/testslotbuilder.nim
new file mode 100644
index 00000000..6eeb1971
--- /dev/null
+++ b/tests/codex/slotbuilder/testslotbuilder.nim
@@ -0,0 +1,17 @@
+import pkg/chronos
+import pkg/asynctest
+import pkg/questionable/results
+import pkg/codex/blocktype as bt
+import pkg/codex/stores/cachestore
+
+import ../helpers
+
+import codex/slotbuilder/slotbuilder
+
+asyncchecksuite "Slot builder":
+  test "a":
+    let builder = SlotBuilder()
+    builder.aaa()
+
+    check:
+      1 == 1