Fix error of empty string passed as parameter

Co-authored-by: Caio Felipe <[email protected]>

api/api/views.py

@@ -6,22 +6,25 @@
 from rest_framework import status
 
 MAXIMUM_RETURNED_DISCIPLINES = 5
+ERROR_MESSAGE = "no valid argument found for 'search', 'year' or 'period'"
+
 
 class Search(APIView):
     def get(self, request: Request, *args, **kwargs) -> Response:
         name = request.GET.get('search', None)
         year = request.GET.get('year', None)
         period = request.GET.get('period', None)
-        
-        if name is None or year is None or period is None:
+
+        if name is None or len(name) == 0 or year is None or len(year) == 0 or period is None or len(period) == 0:
             return Response(
                 {
-                    "errors": "no valid argument found for 'search', 'year' or 'period'"
+                    "errors": ERROR_MESSAGE
                 }, status.HTTP_400_BAD_REQUEST)
 
-        disciplines = filter_disciplines_by_name(name=name) | filter_disciplines_by_code(code=name)
-        filtered_disciplines = filter_disciplines_by_year_and_period(year=year, period=period, disciplines=disciplines)
+        disciplines = filter_disciplines_by_name(
+            name=name) | filter_disciplines_by_code(code=name)
+        filtered_disciplines = filter_disciplines_by_year_and_period(
+            year=year, period=period, disciplines=disciplines)
         data = DisciplineSerializer(filtered_disciplines, many=True).data
 
         return Response(data[:MAXIMUM_RETURNED_DISCIPLINES], status.HTTP_200_OK)
-