diff --git a/lib/mailex/render.ex b/lib/mailex/render.ex
index e825452..026e3fc 100644
--- a/lib/mailex/render.ex
+++ b/lib/mailex/render.ex
@@ -109,13 +109,13 @@ defmodule Mailex.Render do
   def headers_for(email) do
     headers = []
 
-    if  email.reply_to, do:
+    if email.reply_to && (length(email.reply_to) > 0), do:
       headers = [ { "Reply-To", email.reply_to |> stringify_addresses } ]
 
-    if email.bcc, do:
+    if email.bcc && (length(email.bcc) > 0), do:
       headers = [ { "Bcc", email.bcc |> stringify_addresses } | headers ]
 
-    if email.cc, do:
+    if email.cc && (length(email.cc) > 0), do:
       headers = [ { "Cc", email.cc |> stringify_addresses } | headers ]
 
     [ { "From",    email.from |> stringify_addresses },
@@ -124,6 +124,9 @@ defmodule Mailex.Render do
   end
 
 
+  def stringify_addresses(nil), do: ""
+  def stringify_addresses([]),  do: ""
+
   def stringify_addresses(addresses) do
     addresses = addresses |> Address.rfc_822_format
     if is_list(addresses) do
diff --git a/test/mailex_test.exs b/test/mailex_test.exs
index 81491e3..c285108 100644
--- a/test/mailex_test.exs
+++ b/test/mailex_test.exs
@@ -2,7 +2,47 @@ defmodule MailexTest do
   use ExUnit.Case
   doctest Mailex
 
-  test "the truth" do
-    assert 1 + 1 == 2
+  defp email_minimal do
+    %Mailex.Email{
+      from: %Mailex.Address{ address: "test_a@gmail.com" },
+      to:   [%Mailex.Address{ address: "test_b@gmail.com" }]
+    }
   end
+
+  defp email_with_reply_to do
+    %Mailex.Email{
+      from:     %Mailex.Address{ address: "test_a@gmail.com" },
+      to:       [%Mailex.Address{ address: "test_b@gmail.com" }],
+      reply_to: [%Mailex.Address{ address: "test_aa@gmail.com" }, %Mailex.Address{ address: "test_a@gmx.com" }],
+      subject:  "You've got mail",
+      text:     "Hello World!"
+    }
+  end
+
+  defp email_without_attachments do
+    %Mailex.Email{
+      from:    %Mailex.Address{ name: "Yankee", address: "test_a@gmail.com" },
+      to:      [%Mailex.Address{ address: "test_c@gmail.com" }],
+      subject: "You've got mail",
+      text:    "Hello World!"
+    }
+  end
+
+  defp email_with_attachments do
+    %Mailex.Email{
+      from:        %Mailex.Address{ name: "Yankee", address: "test_a@gmail.com" },
+      to:          [%Mailex.Address{ address: "test_c@gmail.com" }],
+      subject:     "You've got mail",
+      text:        "Hello World",
+      attachments: [Mailex.Attachment.inline!("test/data/logo.gif")]
+    }
+  end
+
+  test "Messages render" do
+    assert email_minimal |> Mailex.Render.render
+    assert email_with_reply_to |> Mailex.Render.render
+    assert email_without_attachments |> Mailex.Render.render
+    assert email_with_attachments |> Mailex.Render.render
+  end
+
 end