diff --git a/config/letsencrypt/storage.go b/config/letsencrypt/storage.go
index 54a89599f..ca4405a8d 100644
--- a/config/letsencrypt/storage.go
+++ b/config/letsencrypt/storage.go
@@ -79,6 +79,8 @@ func emailUsername(email string) string {
 	at := strings.Index(email, "@")
 	if at == -1 {
 		return email
+	} else if at == 0 {
+		return email[1:]
 	}
 	return email[:at]
 }
diff --git a/config/letsencrypt/storage_test.go b/config/letsencrypt/storage_test.go
new file mode 100644
index 000000000..812f55010
--- /dev/null
+++ b/config/letsencrypt/storage_test.go
@@ -0,0 +1,66 @@
+package letsencrypt
+
+import "testing"
+
+func TestStorage(t *testing.T) {
+	storage = Storage("./letsencrypt")
+
+	if expected, actual := "letsencrypt/sites", storage.Sites(); actual != expected {
+		t.Errorf("Expected Sites() to return '%s' but got '%s'", expected, actual)
+	}
+	if expected, actual := "letsencrypt/sites/test.com", storage.Site("test.com"); actual != expected {
+		t.Errorf("Expected Site() to return '%s' but got '%s'", expected, actual)
+	}
+	if expected, actual := "letsencrypt/sites/test.com/test.com.crt", storage.SiteCertFile("test.com"); actual != expected {
+		t.Errorf("Expected SiteCertFile() to return '%s' but got '%s'", expected, actual)
+	}
+	if expected, actual := "letsencrypt/sites/test.com/test.com.key", storage.SiteKeyFile("test.com"); actual != expected {
+		t.Errorf("Expected SiteKeyFile() to return '%s' but got '%s'", expected, actual)
+	}
+	if expected, actual := "letsencrypt/sites/test.com/test.com.json", storage.SiteMetaFile("test.com"); actual != expected {
+		t.Errorf("Expected SiteMetaFile() to return '%s' but got '%s'", expected, actual)
+	}
+	if expected, actual := "letsencrypt/users", storage.Users(); actual != expected {
+		t.Errorf("Expected Users() to return '%s' but got '%s'", expected, actual)
+	}
+	if expected, actual := "letsencrypt/users/me@example.com", storage.User("me@example.com"); actual != expected {
+		t.Errorf("Expected User() to return '%s' but got '%s'", expected, actual)
+	}
+	if expected, actual := "letsencrypt/users/me@example.com/me.json", storage.UserRegFile("me@example.com"); actual != expected {
+		t.Errorf("Expected UserRegFile() to return '%s' but got '%s'", expected, actual)
+	}
+	if expected, actual := "letsencrypt/users/me@example.com/me.key", storage.UserKeyFile("me@example.com"); actual != expected {
+		t.Errorf("Expected UserKeyFile() to return '%s' but got '%s'", expected, actual)
+	}
+}
+
+func TestEmailUsername(t *testing.T) {
+	for i, test := range []struct {
+		input, expect string
+	}{
+		{
+			input:  "username@example.com",
+			expect: "username",
+		},
+		{
+			input:  "plus+addressing@example.com",
+			expect: "plus+addressing",
+		},
+		{
+			input:  "me+plus-addressing@example.com",
+			expect: "me+plus-addressing",
+		},
+		{
+			input:  "not-an-email",
+			expect: "not-an-email",
+		},
+		{
+			input:  "@foobar.com",
+			expect: "foobar.com",
+		},
+	} {
+		if actual := emailUsername(test.input); actual != test.expect {
+			t.Errorf("Test %d: Expected username to be '%s' but was '%s'", i, test.expect, actual)
+		}
+	}
+}