Separates policy for file operations

server/utils/__mocks__/s3.ts

@@ -1,3 +1,7 @@
 export const uploadToS3FromBuffer = jest.fn().mockReturnValue("/endpoint/key");
 
 export const publicS3Endpoint = jest.fn().mockReturnValue("http://mock");
+
+export const getSignedUrl = jest.fn().mockReturnValue("http://s3mock");
+
+export const getSignedUrlPromise = jest.fn().mockResolvedValue("http://s3mock");