data: Start Account class.

conservancy_beancount/data.py

@@ -16,6 +16,8 @@
 
 import collections.abc
 
+from beancount.core import account as bc_account
+
 from typing import (
     Iterable,
     Iterator,
@@ -29,6 +31,17 @@ from .beancount_types import (
     Transaction,
 )
 
+class Account(str):
+    SEP = bc_account.sep
+
+    def is_under(self, acct_s: str) -> bool:
+        return self.startswith(acct_s) and (
+            acct_s.endswith(self.SEP)
+            or self == acct_s
+            or self[len(acct_s)] == self.SEP
+        )
+
+
 class PostingMeta(collections.abc.MutableMapping):
     def __init__(self, txn: Transaction, index: int, post: Optional[Posting]=None) -> None:
         if post is None:

tests/test_data_account.py

@@ -0,0 +1,32 @@
+"""Test Account class"""
+# Copyright © 2020  Brett Smith
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+import pytest
+
+from conservancy_beancount import data
+
+@pytest.mark.parametrize('acct_name,under_arg,expected', [
+    ('Expenses:Tax:Sales', 'Expenses:Tax:Sales:', False),
+    ('Expenses:Tax:Sales', 'Expenses:Tax:Sales', True),
+    ('Expenses:Tax:Sales', 'Expenses:Tax:', True),
+    ('Expenses:Tax:Sales', 'Expenses:Tax', True),
+    ('Expenses:Tax:Sales', 'Expenses:', True),
+    ('Expenses:Tax:Sales', 'Expenses', True),
+    ('Expenses:Tax:Sales', 'Accrued:', False),
+    ('Expenses:Tax:Sales', 'Accrued', False),
+])
+def test_is_under(acct_name, under_arg, expected):
+    assert data.Account(acct_name).is_under(under_arg) == expected