diff --git a/test/net/addr/ether.cpp b/test/net/addr/ether.cpp
index 012e1b0..8005906 100644
--- a/test/net/addr/ether.cpp
+++ b/test/net/addr/ether.cpp
@@ -1,3 +1,5 @@
+#include <fmt/format.h>
+
 #include <stdplus/net/addr/ether.hpp>
 
 #include <gtest/gtest.h>
@@ -13,6 +15,20 @@
     std::hash<EtherAddr>{}(EtherAddr{});
 }
 
+TEST(ToStr, EthAddr)
+{
+    ToStrHandle<ToStr<EtherAddr>> tsh;
+    EXPECT_EQ("11:22:33:44:55:66",
+              tsh(EtherAddr{0x11, 0x22, 0x33, 0x44, 0x55, 0x66}));
+    EXPECT_EQ("01:02:03:04:05:67",
+              tsh(EtherAddr{0x01, 0x02, 0x03, 0x04, 0x05, 0x67}));
+    EXPECT_EQ("00:00:00:00:00:00",
+              tsh(ether_addr{0x00, 0x00, 0x00, 0x00, 0x00, 0x00}));
+    EXPECT_EQ(
+        "a 01:02:03:04:05:67 b",
+        fmt::format("a {} b", EtherAddr{0x01, 0x02, 0x03, 0x04, 0x05, 0x67}));
+}
+
 TEST(FromStr, EtherAddr)
 {
     EXPECT_THROW(fromStr<EtherAddr>("0x:00:00:00:00:00"),