diff --git a/gramps/gen/display/test/name_test.py b/gramps/gen/display/test/name_test.py
index b23692f59..ef1480abc 100644
--- a/gramps/gen/display/test/name_test.py
+++ b/gramps/gen/display/test/name_test.py
@@ -21,6 +21,7 @@
 import unittest
 
 from gramps.gen.display.name import NameDisplay
+from gramps.gen.lib import Name
 
 
 class NameTest(unittest.TestCase):
@@ -142,8 +143,100 @@ class NameTest(unittest.TestCase):
         ]
         self.assertEqual(expected_name_format, actual_name_format)
 
+    def test_clear_custom_formats(self):
+        self.add_custom_name_format('Surname, Name|Common Suffix')
+        self.add_inactive_custom_name_format('SURNAME, Given Suffix (Call)')
+
+        self.name_display.clear_custom_formats()
+
+        actual_name_format = self.name_display.get_name_format(also_default=False, only_custom=True, only_active=False)
+
+        self.assertEqual([], actual_name_format)
+
+    def test_do_not_clear_default_formats(self):
+        self.add_custom_name_format('Surname, Name|Common Suffix')
+        self.add_inactive_custom_name_format('SURNAME, Given Suffix (Call)')
+
+        self.name_display.clear_custom_formats()
+
+        actual_name_format = self.name_display.get_name_format(also_default=True, only_custom=False, only_active=False)
+
+        expected_name_format = [
+            (0, 'Default format (defined by Gramps preferences)', '', True),
+            (1, 'Surname, Given Suffix', '%l, %f %s', True),
+            (2, 'Given Surname Suffix', '%f %l %s', True),
+            (3, 'Patronymic, Given', '%y, %s %f', False),
+            (4, 'Given', '%f', True),
+            (5, 'Main Surnames, Given Patronymic Suffix Prefix', '%1m %2m %o, %f %1y %s %0m', True),
+        ]
+
+        self.assertEqual(expected_name_format, actual_name_format)
+
+    def test_set_name_format(self):
+        standard_formats_overrides = [
+            (0, "Default", '', True),
+            (1, "Surname", '%l', True),
+            (2, "Suffix", '%s', True),
+            (3, "Given", '%s', False),
+            (4, "Patronymic", '%y', True),
+            (5, "Prefix", '%0m', True),
+        ]
+
+        self.name_display.set_name_format(standard_formats_overrides)
+
+        actual_name_format = self.name_display.get_name_format(also_default=True, only_custom=False, only_active=False)
+
+        self.assertEqual(standard_formats_overrides, actual_name_format)
+
+    def test_add_existing_name_format(self):
+        self.assertEqual(
+            self.add_custom_name_format('Surname, Name|Common Suffix'),
+            self.add_custom_name_format('Surname, Name|Common Suffix')
+        )
+
+    def test_delete_name_format(self):
+        index = self.add_custom_name_format('Surname, Name|Common Suffix')
+        self.name_display.del_name_format(index)
+
+        actual_name_format = self.name_display.get_name_format(also_default=True, only_custom=True, only_active=True)
+
+        self.assertEqual([], actual_name_format)
+
+    def test_set_default_format_to_custom_format(self):
+        index = self.add_custom_name_format('Surname, Name|Common Suffix')
+        self.name_display.set_default_format(index)
+        self.assertEqual(index, self.name_display.get_default_format())
+
+    def test_set_default_format_to_non_existing_format(self):
+        index = self.name_display.get_default_format()
+        self.name_display.set_default_format(-100)
+        self.assertEqual(index, self.name_display.get_default_format())
+
+    def test_display_name_with_valid_format(self):
+        name = Name()
+        name.set_first_name('William')
+        name.set_call_name('Will')
+        name.set_display_as(4)
+
+        actual_display_name = self.name_display.display_name(name)
+
+        self.assertEqual('William', actual_display_name)
+
+    def test_display_name_with_invalid_format(self):
+        name = Name()
+        name.set_first_name('William')
+        name.set_call_name('Will')
+        name.set_display_as(-100)
+
+        display_name = self.name_display.display_name(name)
+
+        self.assertEqual(', William', display_name)
+
+    def test_display_no_name(self):
+        self.assertEqual('', self.name_display.display_name(None))
+
     def add_custom_name_format(self, name_format):
-        self.name_display.add_name_format(name_format, name_format)
+        return self.name_display.add_name_format(name_format, name_format)
 
     def add_inactive_custom_name_format(self, name_format):
         index = self.name_display.add_name_format(name_format, name_format)