diff --git a/Makefile b/Makefile
index 9a69720..b5bd95d 100644
--- a/Makefile
+++ b/Makefile
@@ -8,7 +8,7 @@ lint:
 
 .PHONY: test
 test:
-	vusted ./lua
+	vusted --output=gtest ./lua
 
 .PHONY: pre-commit
 pre-commit:
diff --git a/README.md b/README.md
index a16ce92..b224465 100644
--- a/README.md
+++ b/README.md
@@ -63,7 +63,7 @@ lua <<EOF
       ['<C-Space>'] = cmp.mapping.complete(),
       ['<C-e>'] = cmp.mapping.close(),
       ['<CR>'] = cmp.mapping.confirm({
-        behavior = cmp.ConfirmBehavior.Replace,
+        behavior = cmp.ConfirmBehavior.Insert,
         select = true,
       })
     },
@@ -261,6 +261,10 @@ cmp.setup {
 }
 ```
 
+#### nvim-cmp is slow.
+
+I optimized nvim-cmp as much as possible but some reason exists maybe.
+
 
 Source creation
 ====================
diff --git a/lua/cmp/config/default.lua b/lua/cmp/config/default.lua
index ea82f94..d2e830a 100644
--- a/lua/cmp/config/default.lua
+++ b/lua/cmp/config/default.lua
@@ -30,7 +30,7 @@ return function()
     },
 
     confirmation = {
-      default_behavior = types.cmp.ConfirmBehavior.Replace,
+      default_behavior = types.cmp.ConfirmBehavior.Insert,
     },
 
     sorting = {