Fix filtering on date.

accountant/api/models/operations.py

@@ -101,8 +101,6 @@ class Operation(db.Model):
 
     @classmethod
     def query(cls, session, begin=None, end=None):
-        end = arrow.now().ceil('month').date() if not end else end
-
         # We have to use a join because the sold is not computed from the
         # begining.
         base_query = session.query(
@@ -124,15 +122,18 @@ class Operation(db.Model):
             cls.canceled
         ).join(
             base_query, base_query.c.id == cls.id
-        ).filter(
-            cls.operation_date >= str(begin),
-            cls.operation_date <= str(end)
         ).order_by(
             desc(cls.operation_date),
             cls.value,
             cls.label,
         )
 
+        if begin:
+            query = query.filter(cls.operation_date >= str(begin))
+
+        if end:
+            query = query.filter(cls.operation_date <= str(end))
+
         return query
 
     @classmethod