added messages templates

internal/domain/login_welcome_template_test.go

@@ -0,0 +1,57 @@
+package domain
+
+import "testing"
+
+func TestResolveWelcomeMessageTemplatePrecedence(t *testing.T) {
+	const panel = "panel override"
+	const env = "env default"
+
+	if got := ResolveWelcomeMessageTemplate(LoginMethodPhone, panel, env); got != panel {
+		t.Fatalf("panel override should win, got %q", got)
+	}
+	if got := ResolveWelcomeMessageTemplate(LoginMethodPhone, "", env); got != env {
+		t.Fatalf("env default should win when panel unset, got %q", got)
+	}
+	if got := ResolveWelcomeMessageTemplate(LoginMethodPhone, "  ", env); got != env {
+		t.Fatalf("whitespace-only panel override should be treated as unset, got %q", got)
+	}
+	if got := ResolveWelcomeMessageTemplate(LoginMethodPhone, "", ""); got != DefaultWelcomeMessagePhoneTemplate {
+		t.Fatalf("built-in phone default should be the final fallback, got %q", got)
+	}
+	if got := ResolveWelcomeMessageTemplate(LoginMethodEmail, "", ""); got != DefaultWelcomeMessageEmailTemplate {
+		t.Fatalf("built-in email default should be the final fallback, got %q", got)
+	}
+}
+
+func TestLoginMethodFromLabel(t *testing.T) {
+	if LoginMethodFromLabel("email") != LoginMethodEmail {
+		t.Fatal("expected email label to map to LoginMethodEmail")
+	}
+	if LoginMethodFromLabel("phone number") != LoginMethodPhone {
+		t.Fatal("expected phone label to map to LoginMethodPhone")
+	}
+	if LoginMethodFromLabel("") != LoginMethodPhone {
+		t.Fatal("expected unknown label to default to LoginMethodPhone")
+	}
+}
+
+func TestRenderWelcomeMessageTemplateSubstitutesServerName(t *testing.T) {
+	SetOfficialSystemUserDisplayName("")
+	defer SetOfficialSystemUserDisplayName("")
+
+	got := RenderWelcomeMessageTemplate("Hello from {{server_name}}!")
+	if got != "Hello from OwpenGram!" {
+		t.Fatalf("expected default branding.ProductName substitution, got %q", got)
+	}
+
+	SetOfficialSystemUserDisplayName("Custom Server")
+	got = RenderWelcomeMessageTemplate("Hello from {{server_name}}!")
+	if got != "Hello from Custom Server!" {
+		t.Fatalf("expected custom display name substitution, got %q", got)
+	}
+
+	// No placeholder present -- must be a no-op.
+	if got := RenderWelcomeMessageTemplate("no placeholder here"); got != "no placeholder here" {
+		t.Fatalf("expected no-op when placeholder absent, got %q", got)
+	}
+}