From da3a7963c3cdc3e9def36cdb25e735cd3950c261 Mon Sep 17 00:00:00 2001
From: vinicius-remote <vinicius@remote.com>
Date: Tue, 11 Jun 2024 14:52:51 -0300
Subject: [PATCH] feat: allow formatted date cells to be empty (#2)

* feat: allow formatted date cells to be empty

* add oracle test

* remove dbg

* Update test/oracle_test.exs
---
 lib/elixlsx/util.ex  |  4 ++++
 test/oracle_test.exs | 10 ++++++++++
 2 files changed, 14 insertions(+)

diff --git a/lib/elixlsx/util.ex b/lib/elixlsx/util.ex
index a2a73be..f9fa99c 100644
--- a/lib/elixlsx/util.ex
+++ b/lib/elixlsx/util.ex
@@ -231,6 +231,10 @@ defmodule Elixlsx.Util do
     {:formula, value}
   end
 
+  @spec to_excel_datetime(binary() | nil) :: binary()
+  def to_excel_datetime(""), do: ""
+  def to_excel_datetime(nil), do: ""
+
   @doc ~S"""
   Replace_all(input, [{search, replace}]).
 
diff --git a/test/oracle_test.exs b/test/oracle_test.exs
index b521ac1..b25f8fb 100644
--- a/test/oracle_test.exs
+++ b/test/oracle_test.exs
@@ -44,4 +44,14 @@ defmodule OracleTest do
 
     assert check(bin)
   end
+
+  test "empty date cells" do
+    s = Sheet.with_name("1") |> Sheet.set_cell("A4", "", yyyymmdd: true)
+
+    wk = %Workbook{} |> Workbook.append_sheet(s)
+
+    assert {:ok, {_, bin}} = Elixlsx.write_to_memory(wk, "")
+
+    assert check(bin)
+  end
 end