diff --git a/tests/forms_tests/widget_tests/test_selectdatewidget.py b/tests/forms_tests/widget_tests/test_selectdatewidget.py
index 24294200c0..3365f11ab7 100644
--- a/tests/forms_tests/widget_tests/test_selectdatewidget.py
+++ b/tests/forms_tests/widget_tests/test_selectdatewidget.py
@@ -478,6 +478,24 @@ class SelectDateWidgetTest(WidgetTest):
             '13-08-1899',
         )
 
+    def test_format_value(self):
+        valid_formats = [
+            '2000-1-1', '2000-10-15', '2000-01-01',
+            '2000-01-0', '2000-0-01', '2000-0-0',
+        ]
+        for value in valid_formats:
+            year, month, day = (int(x) for x in value.split('-'))
+            with self.subTest(value=value):
+                self.assertEqual(self.widget.format_value(value), {'day': day, 'month': month, 'year': year})
+
+        invalid_formats = [
+            '2000-01-001', '2000-001-01', '2-01-01', '20-01-01', '200-01-01',
+            '20000-01-01',
+        ]
+        for value in invalid_formats:
+            with self.subTest(value=value):
+                self.assertEqual(self.widget.format_value(value), {'day': None, 'month': None, 'year': None})
+
     def test_value_omitted_from_data(self):
         self.assertIs(self.widget.value_omitted_from_data({}, {}, 'field'), True)
         self.assertIs(self.widget.value_omitted_from_data({'field_month': '12'}, {}, 'field'), False)