Account: Add is_opening_balance method.

conservancy_beancount/data.py

@@ -78,6 +78,9 @@ class Account(str):
     def is_credit_card(self) -> bool:
         return self.is_under('Liabilities:CreditCard') is not None
 
+    def is_opening_equity(self) -> bool:
+        return self.is_under('Equity:Funds', 'Equity:OpeningBalance') is not None
+
     def is_under(self, *acct_seq: str) -> Optional[str]:
         """Return a match if this account is "under" a part of the hierarchy
 

tests/test_data_account.py

@@ -98,3 +98,20 @@ def test_is_checking(acct_name, expected):
 ])
 def test_is_credit_card(acct_name, expected):
     assert data.Account(acct_name).is_credit_card() == expected
+
+@pytest.mark.parametrize('acct_name,expected', [
+    ('Assets:Cash', False),
+    ('Assets:Prepaid:Expenses', False),
+    ('Assets:Receivable:Accounts', False),
+    ('Expenses:Other', False),
+    ('Equity:Funds:Restricted', True),
+    ('Equity:Funds:Unrestricted', True),
+    ('Equity:OpeningBalance', True),
+    ('Equity:Retained:Costs', False),
+    ('Income:Other', False),
+    ('Liabilities:CreditCard', False),
+    ('Liabilities:Payable:Accounts', False),
+    ('Liabilities:UnearnedIncome:Donations', False),
+])
+def test_is_opening_equity(acct_name, expected):
+    assert data.Account(acct_name).is_opening_equity() == expected