refactor: changed some UTs and JSdocs

TICKET: WP-5443

Author: danielzhao122

modules/express/src/typedRoutes/api/v2/ofcSignPayload.ts

@@ -9,11 +9,11 @@ import { BitgoExpressError } from '../../schemas/error';
 export const OfcSignPayloadBody = {
   /** The ID of the OFC wallet to sign the payload with. */
   walletId: NonEmptyString,
-  /** The payload to sign. Will always decode into a JSON object. */
+  /** The payload to sign. The input can either be a stringified JSON, or a JSON object. */
   payload: t.union([Json, t.string.pipe(JsonFromString)]),
   /** The passphrase to decrypt the user key. */
   walletPassphrase: optional(t.string),
-};
+} as const;
 
 export const OfcSignPayloadResponse200 = t.type({
   /** The string form of the JSON payload that was signed. */

modules/express/test/unit/clientRoutes/signPayload.ts

@@ -61,7 +61,10 @@ describe('Sign an arbitrary payload with trading account key', function () {
       },
       query: {},
     } as unknown as ExpressApiRouteRequest<'express.ofc.signPayload', 'post'>;
-    await handleV2OFCSignPayload(req).should.be.resolvedWith(expectedResponse);
+    const result = await handleV2OFCSignPayload(req).should.be.resolvedWith(expectedResponse);
+    decodeOrElse('OfcSignPayloadResponse200', OfcSignPayloadResponse[200], result, (_) => {
+      throw new Error(`Response did not match expected codec`);
+    });
   });
   it('should return a signed payload with type as json string', async function () {
     const expectedResponse = {
@@ -80,7 +83,10 @@ describe('Sign an arbitrary payload with trading account key', function () {
       },
       query: {},
     } as unknown as ExpressApiRouteRequest<'express.ofc.signPayload', 'post'>;
-    await handleV2OFCSignPayload(req).should.be.resolvedWith(expectedResponse);
+    const result = await handleV2OFCSignPayload(req).should.be.resolvedWith(expectedResponse);
+    decodeOrElse('OfcSignPayloadResponse200', OfcSignPayloadResponse[200], result, (_) => {
+      throw new Error(`Response did not match expected codec`);
+    });
   });
   it('should decode handler response with OfcSignPayloadResponse codec', async function () {
     const expected = {