diff --git a/tests/test_dates.py b/tests/test_dates.py
new file mode 100644
index 0000000..1060e7a
--- /dev/null
+++ b/tests/test_dates.py
@@ -0,0 +1,152 @@
+"""Unit tests for the `dates` module."""
+
+import datetime as dt
+from unittest import mock
+
+import pytest
+from hypothesis import assume, given
+from hypothesis import strategies as st
+
+from parliai_public import dates
+
+from .common import ST_DATES, TODAY
+
+
+def check_date_list(date_list, start, end):
+    """Check the properties of the date list itself."""
+
+    assert isinstance(date_list, list)
+    assert all(isinstance(date, dt.date) for date in date_list)
+    assert min(date_list) == start
+    assert max(date_list) == end
+
+    for i, date in enumerate(date_list[:-1]):
+        assert (date_list[i + 1] - date).days == 1
+
+
+def check_mocked_components(
+    formatter, checker, start=None, end=None, window=None
+):
+    """Check the formatter and checker mocked objects."""
+
+    assert formatter.call_count == 2
+    assert formatter.call_args_list == [
+        mock.call(limit, "%Y-%m-%d") for limit in (start, end)
+    ]
+
+    checker.assert_called_once_with(start, end, window)
+
+
+@given(
+    st.tuples(ST_DATES, ST_DATES).map(sorted),
+    st.one_of(st.just(None), st.integers(1, 14)),
+)
+def test_list_dates_with_endpoints(endpoints, window):
+    """
+    Check the date lister works for start and end points.
+
+    We also check that the end points are always used even when a window
+    is also provided.
+    """
+
+    start, end = endpoints
+
+    with (
+        mock.patch("parliai_public.dates._format_date") as formatter,
+        mock.patch("parliai_public.dates._check_date_parameters") as checker,
+    ):
+        formatter.side_effect = [start, end]
+        date_list = dates.list_dates(start, end, window)
+
+    check_date_list(date_list, start, end)
+    check_mocked_components(formatter, checker, start, end, window)
+
+
+@given(ST_DATES, st.integers(1, 14))
+def test_list_dates_with_look_behind(end, window):
+    """Check the date lister works for looking back from an endpoint."""
+
+    with (
+        mock.patch("parliai_public.dates._format_date") as formatter,
+        mock.patch("parliai_public.dates._check_date_parameters") as checker,
+    ):
+        formatter.side_effect = [None, end]
+        date_list = dates.list_dates(end=end, window=window)
+
+    check_date_list(date_list, end - dt.timedelta(window - 1), end)
+    check_mocked_components(formatter, checker, end=end, window=window)
+
+
+@given(ST_DATES)
+def test_list_dates_with_single_date(end):
+    """Check the date lister works for a single date."""
+
+    with (
+        mock.patch("parliai_public.dates._format_date") as formatter,
+        mock.patch("parliai_public.dates._check_date_parameters") as checker,
+    ):
+        formatter.side_effect = [None, end]
+        date_list = dates.list_dates(end=end)
+
+    check_date_list(date_list, end, end)
+    check_mocked_components(formatter, checker, end=end)
+
+
+@given(st.one_of(st.just(None), ST_DATES))
+def test_format_date_with_none_or_date(date):
+    """Check the date formatter does nothing with `None` or a date."""
+
+    assert dates._format_date(date) is date
+
+
+@given(st.datetimes(min_value=dt.datetime(2000, 1, 1)))
+def test_format_date_with_datetime(datetime):
+    """Check the date formatter works for datetime objects."""
+
+    assert dates._format_date(datetime) == datetime.date()
+
+
+@given(ST_DATES, st.sampled_from(("%Y-%m-%d", "%d/%m/%Y", "%a, %d %b %Y")))
+def test_format_date_with_date_string(date, form):
+    """Check the date formatter works for date strings."""
+
+    assert dates._format_date(date.strftime(form), form) == date
+
+
+@given(ST_DATES, st.integers(1, 14))
+def test_check_date_parameters_warns_for_start_and_window(start, window):
+    """Check the date parameter checker warns given start and window."""
+
+    with pytest.warns(UserWarning, match="Ignoring window"):
+        dates._check_date_parameters(start, TODAY, window)
+
+
+@given(st.dates(min_value=TODAY + dt.timedelta(days=1)))
+def test_check_date_parameters_raises_for_end_in_the_future(end):
+    """Check the date parameter checker raises given a future end."""
+
+    message = "End date must not be in the future."
+    with pytest.raises(ValueError, match=message):
+        dates._check_date_parameters(None, end, None)
+
+
+@given(st.dates(min_value=TODAY + dt.timedelta(days=1)))
+def test_check_date_parameters_raises_for_start_in_the_future(start):
+    """Check the date parameter checker raises given a future start."""
+
+    message = "Start date must not be in the future."
+    with pytest.raises(ValueError, match=message):
+        dates._check_date_parameters(start, TODAY, None)
+
+
+@given(st.tuples(ST_DATES, ST_DATES).map(sorted))
+def test_check_date_parameters_raises_for_start_after_end(endpoints):
+    """Check the checker raises given a start later than its end."""
+
+    end, start = endpoints
+
+    assume(start != end)
+
+    message = "Start date must not be after end date."
+    with pytest.raises(ValueError, match=message):
+        dates._check_date_parameters(start, end, None)