tests: Add test for rename/delete budget exception.

tests/test_api.py

@@ -1,7 +1,7 @@
 import pytest
 
 from actual import Actual
-from actual.exceptions import ActualError
+from actual.exceptions import ActualError, UnknownFileId
 from actual.protobuf_models import Message
 
 
@@ -16,3 +16,12 @@ def test_api_apply(mocker):
     m.dataset = "accounts"
     with pytest.raises(ActualError, match="column 'bar' at table 'accounts' not found"):
         actual.apply_changes([m])
+
+
+def test_rename_delete_budget_without_file():
+    actual = Actual.__new__(Actual)
+    actual._file = None
+    with pytest.raises(UnknownFileId, match="No current file loaded"):
+        actual.delete_budget()
+    with pytest.raises(UnknownFileId, match="No current file loaded"):
+        actual.rename_budget("foo")