Use multiple date formats in DateRange validator

tests/domain/test_date.py

@@ -0,0 +1,21 @@
+import pytest
+import pendulum
+
+from atst.domain.date import parse_date
+
+
+def test_date_with_slashes():
+    date_str = "1/2/2020"
+    assert parse_date(date_str) == pendulum.date(2020, 1, 2)
+
+
+def test_date_with_dashes():
+    date_str = "2020-1-2"
+    assert parse_date(date_str) == pendulum.date(2020, 1, 2)
+
+
+def test_invalid_date():
+    date_str = "This is not a valid data"
+    with pytest.raises(ValueError):
+        parse_date(date_str)
+