diff --git a/tests/test_base.py b/tests/test_base.py
index efa1bc81..c9abe14d 100644
--- a/tests/test_base.py
+++ b/tests/test_base.py
@@ -62,3 +62,27 @@ def test_is_title(self):
             self.base.title("one"),
             "one"
             )
+
+    def test_set_high_numwords_not_implemented(self):
+        with self.assertRaises(NotImplementedError):
+            self.base.set_high_numwords()
+
+    def test_to_ordinal_num(self):
+        from num2words.base import Num2Word_Base
+        self.base = Num2Word_Base()
+        self.assertEqual(
+            self.base.to_ordinal_num(1),
+            1
+        )
+        self.assertEqual(
+            self.base.to_ordinal_num(100),
+            100
+        )
+        self.assertEqual(
+            self.base.to_ordinal_num(1000),
+            1000
+        )
+
+    def test_pluralize_not_implemented(self):
+        with self.assertRaises(NotImplementedError):
+            self.base.pluralize(n=None, forms=None)