diff --git a/tests/test_books_loader.py b/tests/test_books_loader.py
new file mode 100644
index 0000000000000000000000000000000000000000..fb92e4ac1f68528d0d1eb95ec75453a952a88612
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+++ b/tests/test_books_loader.py
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+"""test_books_loader - Unit tests for books Loader 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/>.
+
+from datetime import date
+from pathlib import Path
+
+import pytest
+
+from . import testutil
+
+from conservancy_beancount import books
+
+books_path = testutil.test_path('booksroot')
+
+@pytest.fixture(scope='module')
+def conservancy_loader():
+    return books.Loader(books_path, books.FiscalYear(3))
+
+def format_include(year, subdir=''):
+    path = Path(books_path, subdir, f'{year}.beancount')
+    return f'include "{path}"'
+
+def format_plugin(name, optstring=None):
+    if optstring is None:
+        return f'plugin "{name}"'
+    else:
+        return f'plugin "{name}" "{optstring}"'
+
+def expect_string(years, plugins={'conservancy_beancount.plugin': None}):
+    years = iter(years)
+    year1_s = format_include(next(years), 'books')
+    return '\n'.join([
+        *(format_plugin(name, opts) for name, opts in plugins.items()),
+        year1_s,
+        *(format_include(year) for year in years),
+    ])
+
+@pytest.mark.parametrize('range_start,range_stop,expect_years', [
+    (2019, 2020, [2019, 2020]),
+    (-1, 2020, [2019, 2020]),
+    (date(2019, 1, 1), date(2020, 6, 1), range(2018, 2021)),
+    (-1, date(2020, 2, 1), [2018, 2019]),
+])
+def test_fy_range_string(conservancy_loader, range_start, range_stop, expect_years):
+    expected = expect_string(expect_years)
+    assert conservancy_loader.fy_range_string(range_start, range_stop) == expected
+
+@pytest.mark.parametrize('year_offset', range(-3, 1))
+def test_fy_range_string_one_offset(conservancy_loader, year_offset):
+    this_year = date.today().year
+    expected = expect_string(range(this_year + year_offset, this_year + 1))
+    assert conservancy_loader.fy_range_string(year_offset) == expected
+
+@pytest.mark.parametrize('plugins', [
+    {},
+    {'conservancy_beancount.plugin': '-all'},
+])
+def test_fy_range_string_plugins_override(conservancy_loader, plugins):
+    expected = expect_string([2019, 2020], plugins)
+    assert conservancy_loader.fy_range_string(2019, 2020, plugins) == expected
+
+def test_fy_range_string_empty_range(conservancy_loader):
+    assert conservancy_loader.fy_range_string(2020, 2019) == ''