Add test for calculateLength()

Signed-off-by: Fred Boniface <fred@fjla.uk>

src/utils/translators/ldb/staffStation.ts

@@ -104,15 +104,15 @@ function transformLocation(input: any): ServiceLocation[] {
   return output
 }
 
-function calculateLength(input: TrainServices): number | undefined {
+export function calculateLength(input: any): number | undefined {
   let length: number;
   if (input?.length) {
     length = input.length
-    return length
+    return Number(length)
   }
   if (input?.formation?.coaches?.coach) {
     length = input.formation.coaches.coach.length
-    return length
+    return Number(length)
   }
   return undefined
 }