feat(admission): add group VPN exceptions

apps/web/src/lib/admission-settings.test.ts

@@ -0,0 +1,33 @@
+import { describe, expect, it } from "vitest";
+import { admissionDenialMessage, DEFAULT_ADMISSION_MESSAGES, parseAdmissionMessages } from "./admission-settings";
+
+describe("admission message settings", () => {
+  it("normalizes three independently configured denial messages", () => {
+    const formData = new FormData();
+    formData.set("registrationMessage", "  Register your account before joining.  ");
+    formData.set("groupAccessDeniedMessage", "This group cannot access the server right now.");
+    formData.set("vpnDeniedMessage", "VPN access requires a host-approved exception.");
+
+    expect(parseAdmissionMessages(formData)).toEqual({
+      registrationMessage: "Register your account before joining.",
+      groupAccessDeniedMessage: "This group cannot access the server right now.",
+      vpnDeniedMessage: "VPN access requires a host-approved exception.",
+    });
+  });
+
+  it("selects the configured message for each admission denial reason", () => {
+    expect(admissionDenialMessage("not_registered", DEFAULT_ADMISSION_MESSAGES)).toBe(DEFAULT_ADMISSION_MESSAGES.registrationMessage);
+    expect(admissionDenialMessage("group_access_disabled", DEFAULT_ADMISSION_MESSAGES)).toBe(DEFAULT_ADMISSION_MESSAGES.groupAccessDeniedMessage);
+    expect(admissionDenialMessage("anonymized_network_disallowed", DEFAULT_ADMISSION_MESSAGES)).toBe(DEFAULT_ADMISSION_MESSAGES.vpnDeniedMessage);
+  });
+
+  it("rejects missing, short, overlong, or control-character messages", () => {
+    for (const invalid of ["short", "a".repeat(501), "Denied\nInjected"] as const) {
+      const formData = new FormData();
+      formData.set("registrationMessage", DEFAULT_ADMISSION_MESSAGES.registrationMessage);
+      formData.set("groupAccessDeniedMessage", DEFAULT_ADMISSION_MESSAGES.groupAccessDeniedMessage);
+      formData.set("vpnDeniedMessage", invalid);
+      expect(parseAdmissionMessages(formData)).toBeNull();
+    }
+  });
+});