fix: getUploadUrl testing woe

lib/lambda/getUploadUrl.test.ts

@@ -1,4 +1,4 @@
-import { describe, it, expect, vi, beforeEach } from "vitest";
+import { describe, it, expect, vi, beforeEach, Mock } from "vitest";
 import { APIGatewayEvent } from "aws-lambda";
 import { handler } from "./getUploadUrl";
 import { response } from "libs/handler-lib";
@@ -27,7 +27,7 @@ describe("Handler for generating signed URL", () => {
     vi.clearAllMocks();
     process.env.attachmentsBucketName = "test-bucket";
     process.env.attachmentsBucketRegion = "test-region";
-    (uuidv4 as vi.Mock).mockReturnValue("123e4567-e89b-12d3-a456-426614174000");
+    (uuidv4 as Mock).mockReturnValue("123e4567-e89b-12d3-a456-426614174000");
   });
 
   it("should return 400 if event body is missing", async () => {
@@ -43,7 +43,7 @@ describe("Handler for generating signed URL", () => {
 
   it("should return 200 with signed URL, bucket, and key", async () => {
     const mockUrl = "https://example.com/signed-url";
-    (getSignedUrl as vi.Mock).mockResolvedValueOnce(mockUrl);
+    (getSignedUrl as Mock).mockResolvedValueOnce(mockUrl);
 
     const event = {
       body: JSON.stringify({ fileName: "test-file.pdf" }),
@@ -63,7 +63,7 @@ describe("Handler for generating signed URL", () => {
   });
 
   it("should return 500 if an error occurs during processing", async () => {
-    (getSignedUrl as vi.Mock).mockRejectedValueOnce(new Error("Test error"));
+    (getSignedUrl as Mock).mockRejectedValueOnce(new Error("Test error"));
 
     const event = {
       body: JSON.stringify({ fileName: "test-file.pdf" }),
@@ -77,9 +77,14 @@ describe("Handler for generating signed URL", () => {
     });
   });
 
-  it("should throw an error if required environment variables are missing", () => {
+  it("should throw an error if required environment variables are missing", async () => {
     delete process.env.attachmentsBucketName;
 
-    expect(() => handler({} as APIGatewayEvent)).toThrowError();
+    await handler({} as APIGatewayEvent);
+
+    expect(response).toHaveBeenCalledWith({
+      statusCode: 500,
+      body: { message: "Internal server error" },
+    });
   });
 });

lib/lambda/getUploadUrl.ts

@@ -11,9 +11,10 @@ const s3 = new S3Client({
 });
 
 export const handler = async (event: APIGatewayEvent) => {
-  validateEnvVariable("attachmentsBucketName");
-  validateEnvVariable("attachmentsBucketRegion");
   try {
+    validateEnvVariable("attachmentsBucketName");
+    validateEnvVariable("attachmentsBucketRegion");
+
     if (!event.body) {
       return response({
         statusCode: 400,