test: add problemDetails test code

__tests__/unit/models/problemDetails.test.ts

@@ -0,0 +1,71 @@
+import { expect, test } from "vitest";
+import {
+  isProblemDetails,
+  ProblemDetails
+} from "../../../src/models/problemDetails";
+
+test("should return true when value is a ProblemDetails object", () => {
+  const value: ProblemDetails = {
+    title: "Internal Server Error",
+    status: 500,
+    detail: "An unexpected error occurred.",
+    instance: "/api/users",
+    errors: ["500", "Internal Server Error"]
+  };
+  const result = isProblemDetails(value);
+
+  expect(result).toBe(true);
+});
+
+test("should return false when value is not an object", () => {
+  const value = "Invalid input";
+  const result = isProblemDetails(value);
+
+  expect(result).toBe(false);
+});
+
+test("should return false when value is null", () => {
+  const value = null;
+  const result = isProblemDetails(value);
+
+  expect(result).toBe(false);
+});
+
+test("should return false when status is not a number", () => {
+  const value = {
+    title: "Bad Request",
+    status: "400",
+    detail: "Invalid request.",
+    instance: "/api/users",
+    errors: ["400", "Bad Request"]
+  };
+  const result = isProblemDetails(value);
+
+  expect(result).toBe(false);
+});
+
+test("should return true when errors is an array", () => {
+  const value: ProblemDetails = {
+    title: "Not Found",
+    status: 404,
+    detail: "Resource not found.",
+    instance: "/api/users",
+    errors: ["", ""]
+  };
+  const result = isProblemDetails(value);
+
+  expect(result).toBe(true);
+});
+
+test("should return false when errors is not an array", () => {
+  const value = {
+    title: "Unauthorized",
+    status: 401,
+    detail: "Access denied.",
+    instance: "/api/users",
+    errors: "401"
+  };
+  const result = isProblemDetails(value);
+
+  expect(result).toBe(false);
+});

src/models/problemDetails.ts

@@ -7,7 +7,6 @@ export interface ProblemDetails {
   errors: [code: string, message: string];
 }
 
-// TODO: Write test code
 export function isProblemDetails(value: unknown): value is ProblemDetails {
   if (typeof value !== "object" || value === null) {
     return false;