refactor getMi for better not found handling

Author: RossFaulds171

lambdas/api-handler/src/services/mi-operations.ts

@@ -1,6 +1,15 @@
 import { MIRepository } from "@internal/datastore/src/mi-repository";
 import { GetMIResponse, IncomingMI, PostMIResponse } from "../contracts/mi";
 import { mapToGetMIResponse, mapToPostMIResponse } from "../mappers/mi-mapper";
+import { ApiErrorDetail } from "../contracts/errors";
+import NotFoundError from "../errors/not-found-error";
+
+function isNotFoundError(error: any) {
+  return (
+    error instanceof Error &&
+    /^Management Information with id \w+ not found for supplier \w+$/.test(error.message)
+  );
+}
 
 export const postMI = async (
   incomingMi: IncomingMI,
@@ -14,5 +23,15 @@ export const getMI = async (
   supplierId: string,
   miRepo: MIRepository,
 ): Promise<GetMIResponse> => {
-  return mapToGetMIResponse(await miRepo.getMI(miId, supplierId));
+  let mi;
+
+  try {
+    mi = await miRepo.getMI(miId, supplierId);
+  } catch (error) {
+    if (isNotFoundError(error)) {
+      throw new NotFoundError(ApiErrorDetail.NotFoundId);
+    }
+    throw error;
+  }
+  return mapToGetMIResponse(mi);
 };