diff --git a/tests/test_opening_balances.py b/tests/test_opening_balances.py
new file mode 100644
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+++ b/tests/test_opening_balances.py
@@ -0,0 +1,150 @@
+"""test_tools_opening_balances.py - Unit tests for opening balance generation"""
+# 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 collections
+import copy
+import datetime
+import io
+
+import pytest
+
+from . import testutil
+
+from beancount import loader as bc_loader
+from conservancy_beancount.tools import opening_balances as openbalmod
+
+from decimal import Decimal
+from typing import NamedTuple, Optional
+
+A_CHECKING = 'Assets:Checking'
+A_EUR = 'Assets:EUR'
+A_PREPAID = 'Assets:Prepaid:Expenses'
+A_RECEIVABLE = 'Assets:Receivable:Accounts'
+A_RESTRICTED = 'Equity:Funds:Restricted'
+A_UNRESTRICTED = 'Equity:Funds:Unrestricted'
+A_CURRCONV = 'Equity:Realized:CurrencyConversion'
+A_CREDITCARD = 'Liabilities:CreditCard'
+A_PAYABLE = 'Liabilities:Payable:Accounts'
+A_UNEARNED = 'Liabilities:UnearnedIncome'
+
+class FlatPosting(NamedTuple):
+    account: str
+    units_number: Decimal
+    units_currency: str
+    cost_number: Optional[Decimal]
+    cost_currency: Optional[str]
+    cost_date: Optional[datetime.date]
+    project: Optional[str]
+
+    def __repr__(self):
+        cost_s = f' {{{self.cost_number} {self.cost_currency}, {self.cost_date}}}'
+        if cost_s == ' {None None, None}':
+            cost_s = ''
+        return f'<{self.account}  {self.units_number} {self.units_currency}{cost_s}>'
+
+    @classmethod
+    def make(cls,
+             account,
+             units_number,
+             units_currency='USD',
+             cost_number=None,
+             cost_date=None,
+             project=None,
+             cost_currency=None,
+    ):
+        if cost_number is not None:
+            cost_number = Decimal(cost_number)
+            if cost_currency is None:
+                cost_currency = 'USD'
+            if isinstance(cost_date, str):
+                cost_date = datetime.datetime.strptime(cost_date, '%Y-%m-%d').date()
+        return cls(account, Decimal(units_number), units_currency,
+                   cost_number, cost_currency, cost_date, project)
+
+    @classmethod
+    def from_beancount(cls, posting):
+        units_number, units_currency = posting.units
+        if posting.cost is None:
+            cost_number = cost_currency = cost_date = None
+        else:
+            cost_number, cost_currency, cost_date, _ = posting.cost
+        try:
+            project = posting.meta['project']
+        except (AttributeError, KeyError):
+            project = None
+        return cls(posting.account, units_number, units_currency,
+                   cost_number, cost_currency, cost_date, project)
+
+    @classmethod
+    def from_output(cls, output):
+        entries, _, _ = bc_loader.load_string(output.read())
+        return (cls.from_beancount(post) for post in entries[-1].postings)
+
+
+def run_main(arglist, config=None):
+    if config is None:
+        config = testutil.TestConfig(
+            books_path=testutil.test_path('books/fund.beancount'),
+        )
+    output = io.StringIO()
+    errors = io.StringIO()
+    retcode = openbalmod.main(arglist, output, errors, config)
+    output.seek(0)
+    return retcode, output, errors
+
+@pytest.mark.parametrize('arg', ['2018', '2018-03-01'])
+def test_2018_opening(arg):
+    retcode, output, errors = run_main([arg])
+    assert not errors.getvalue()
+    assert retcode == 0
+    assert list(FlatPosting.from_output(output)) == [
+        FlatPosting.make(A_CHECKING, 10000),
+        FlatPosting.make(A_RESTRICTED, -3000, project='Alpha'),
+        FlatPosting.make(A_RESTRICTED, -2000, project='Bravo'),
+        FlatPosting.make(A_RESTRICTED, -1000, project='Charlie'),
+        FlatPosting.make(A_UNRESTRICTED, -4000, project='Conservancy'),
+    ]
+
+@pytest.mark.parametrize('arg', ['2019', '2019-03-01'])
+def test_2019_opening(arg):
+    retcode, output, errors = run_main([arg])
+    assert not errors.getvalue()
+    assert retcode == 0
+    assert list(FlatPosting.from_output(output)) == [
+        FlatPosting.make(A_CHECKING, 10050),
+        FlatPosting.make(A_PREPAID, 20, project='Alpha'),
+        FlatPosting.make(A_RECEIVABLE, 32, 'EUR', '1.25', '2018-03-03', 'Conservancy'),
+        FlatPosting.make(A_RESTRICTED, -3060, project='Alpha'),
+        FlatPosting.make(A_RESTRICTED, -1980, project='Bravo'),
+        FlatPosting.make(A_RESTRICTED, -1000, project='Charlie'),
+        FlatPosting.make(A_UNRESTRICTED, -4036, project='Conservancy'),
+        FlatPosting.make(A_PAYABLE, -4, project='Conservancy'),
+        FlatPosting.make(A_UNEARNED, -30, project='Alpha'),
+    ]
+
+@pytest.mark.parametrize('arg', ['2020', '2020-12-31'])
+def test_2020_opening(arg):
+    retcode, output, errors = run_main([arg])
+    assert not errors.getvalue()
+    assert retcode == 0
+    assert list(FlatPosting.from_output(output)) == [
+        FlatPosting.make(A_CHECKING, 10276),
+        FlatPosting.make(A_EUR, 32, 'EUR', '1.5', '2019-03-03'),
+        FlatPosting.make(A_RESTRICTED, -3064, project='Alpha'),
+        FlatPosting.make(A_RESTRICTED, -2180, project='Bravo'),
+        FlatPosting.make(A_RESTRICTED, -1000, project='Charlie'),
+        FlatPosting.make(A_UNRESTRICTED, -4080, project='Conservancy'),
+    ]