diff --git a/crates/kumod/src/smtp_server.rs b/crates/kumod/src/smtp_server.rs
index b3541080..1d875ef4 100644
--- a/crates/kumod/src/smtp_server.rs
+++ b/crates/kumod/src/smtp_server.rs
@@ -303,14 +303,11 @@ mod test {
         );
         assert_equal!(
             Command::parse("MAIL From:<>").unwrap(),
-            Command::Mail(EnvelopeAddress::Null)
+            Command::Mail(EnvelopeAddress::null_sender())
         );
         assert_equal!(
             Command::parse("MAIL From:<user@example.com>").unwrap(),
-            Command::Mail(EnvelopeAddress::Mailbox {
-                user: "user".to_string(),
-                domain: "example.com".to_string()
-            })
+            Command::Mail(EnvelopeAddress::parse("user@example.com").unwrap())
         );
         assert_equal!(
             Command::parse("rcpt to:<>").unwrap_err().to_string(),
@@ -318,10 +315,7 @@ mod test {
         );
         assert_equal!(
             Command::parse("rcpt TO:<user@example.com>").unwrap(),
-            Command::Rcpt(EnvelopeAddress::Mailbox {
-                user: "user".to_string(),
-                domain: "example.com".to_string()
-            })
+            Command::Rcpt(EnvelopeAddress::parse("user@example.com").unwrap())
         );
     }
 }
diff --git a/crates/message/src/address.rs b/crates/message/src/address.rs
index f7ccca82..c11a7cce 100644
--- a/crates/message/src/address.rs
+++ b/crates/message/src/address.rs
@@ -8,7 +8,7 @@ pub struct EnvelopeAddress(String);
 impl EnvelopeAddress {
     pub fn parse(text: &str) -> anyhow::Result<Self> {
         if text.is_empty() {
-            Ok(Self("".to_string()))
+            Ok(Self::null_sender())
         } else {
             let fields: Vec<&str> = text.split('@').collect();
             anyhow::ensure!(fields.len() == 2, "expected user@domain");
@@ -30,6 +30,10 @@ impl EnvelopeAddress {
             None => "",
         }
     }
+
+    pub fn null_sender() -> Self {
+        Self("".to_string())
+    }
 }
 
 impl UserData for EnvelopeAddress {
diff --git a/crates/message/src/lib.rs b/crates/message/src/lib.rs
index 35999410..64dc7dc7 100644
--- a/crates/message/src/lib.rs
+++ b/crates/message/src/lib.rs
@@ -1,5 +1,5 @@
 pub mod address;
 pub mod message;
 
-pub use address::EnvelopeAddress;
-pub use message::Message;
+pub use crate::address::EnvelopeAddress;
+pub use crate::message::Message;