diff --git a/internal/backends/memory/rooms_test.go b/internal/backends/memory/rooms_test.go
index 0d3543e..ea0029a 100644
--- a/internal/backends/memory/rooms_test.go
+++ b/internal/backends/memory/rooms_test.go
@@ -1,7 +1,6 @@
 package memory
 
 import (
-	"strings"
 	"testing"
 
 	"github.com/nxshock/signaller/internal/models/createroom"
@@ -9,23 +8,6 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func TestRegisterUser(t *testing.T) {
-	backend := NewBackend("localhost")
-
-	var (
-		username = "user1"
-		password = "password1"
-		device   = "device1"
-	)
-
-	user, token, err := backend.Register(username, password, device)
-	assert.Nil(t, err)
-	assert.Equal(t, username, user.Name())
-	assert.Equal(t, password, user.Password())
-	assert.NotEmpty(t, token)
-	assert.True(t, strings.HasSuffix(user.ID(), backend.hostname))
-}
-
 func TestCreateRoom(t *testing.T) {
 	backend := NewBackend("localhost")
 
diff --git a/internal/backends/memory/user_test.go b/internal/backends/memory/user_test.go
new file mode 100644
index 0000000..11673fe
--- /dev/null
+++ b/internal/backends/memory/user_test.go
@@ -0,0 +1,37 @@
+package memory
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRegisterUser(t *testing.T) {
+	backend := NewBackend("localhost")
+
+	var (
+		username = "user1"
+		password = "password1"
+		device   = "device1"
+	)
+
+	user, token, err := backend.Register(username, password, device)
+	assert.Nil(t, err)
+	assert.Equal(t, username, user.Name())
+	assert.Equal(t, password, user.Password())
+	assert.NotEmpty(t, token)
+}
+
+func TestUserID(t *testing.T) {
+	var (
+		userName       = "user1"
+		hostName       = "localhost"
+		expectedUserID = "@user1:localhost"
+	)
+
+	backend := NewBackend(hostName)
+	user, _, err := backend.Register(userName, "", "")
+	assert.Nil(t, err)
+
+	assert.Equal(t, expectedUserID, user.ID())
+}