test(chat): add test for defaulting nullable content to an empty string

src/data/dto/chat/__tests__/unlock_private_response.test.ts

@@ -61,4 +61,22 @@ describe("UnlockPrivateResponse", () => {
     expect(response.shortfallCredits).toBe(5);
     expect(response.lockDetail.showUpgrade).toBe(true);
   });
+
+  it("defaults nullable content to an empty string", () => {
+    const response = UnlockPrivateResponse.from({
+      unlocked: false,
+      content: null,
+      reason: "insufficient_balance",
+      lockDetail: {
+        locked: true,
+        showContent: false,
+        showUpgrade: true,
+        reason: "insufficient_balance",
+        hint: null,
+        detail: null,
+      },
+    });
+
+    expect(response.content).toBe("");
+  });
 });

src/data/schemas/chat/unlock_private_response.ts

@@ -1,5 +1,6 @@
 import { z } from "zod";
 
+import { stringOrEmpty } from "../nullable-defaults";
 import { ChatLockDetailSchema } from "./chat_payloads";
 
 /**
@@ -9,7 +10,7 @@ export const UnlockPrivateReasonSchema = z.string().default("");
 
 export const UnlockPrivateResponseSchema = z.object({
   unlocked: z.boolean(),
-  content: z.string().default(""),
+  content: stringOrEmpty,
   reason: UnlockPrivateReasonSchema,
   creditBalance: z.number().default(0),
   creditsCharged: z.number().default(0),