diff --git a/Lib/test/string_tests.py b/Lib/test/string_tests.py
index ef995e2..4345687 100644
--- a/Lib/test/string_tests.py
+++ b/Lib/test/string_tests.py
@@ -1179,7 +1179,8 @@
         self.checkraises(TypeError, 'abc', '__mod__')
         self.checkraises(TypeError, '%(foo)s', '__mod__', 42)
         self.checkraises(TypeError, '%s%s', '__mod__', (42,))
-        self.checkraises(TypeError, '%c', '__mod__', (None,))
+        with self.assertWarns(DeprecationWarning):
+            self.checkraises(TypeError, '%c', '__mod__', (None,))
         self.checkraises(ValueError, '%(foo', '__mod__', {})
         self.checkraises(TypeError, '%(foo)s %(bar)s', '__mod__', ('foo', 42))
         self.checkraises(TypeError, '%d', '__mod__', "42") # not numeric
diff --git a/Lib/test/test_format.py b/Lib/test/test_format.py
index 29330f9..015d68e 100644
--- a/Lib/test/test_format.py
+++ b/Lib/test/test_format.py
@@ -142,7 +142,8 @@
         testformat("%#+027.23X", big, "+0X0001234567890ABCDEF12345")
         # same, except no 0 flag
         testformat("%#+27.23X", big, " +0X001234567890ABCDEF12345")
-        testformat("%x", float(big), "123456_______________", 6)
+        with self.assertWarns(DeprecationWarning):
+            testformat("%x", float(big), "123456_______________", 6)
         big = 0o12345670123456701234567012345670  # 32 octal digits
         testformat("%o", big, "12345670123456701234567012345670")
         testformat("%o", -big, "-12345670123456701234567012345670")
@@ -182,7 +183,8 @@
         testformat("%034.33o", big, "0012345670123456701234567012345670")
         # base marker shouldn't change that
         testformat("%0#34.33o", big, "0o012345670123456701234567012345670")
-        testformat("%o", float(big), "123456__________________________", 6)
+        with self.assertWarns(DeprecationWarning):
+            testformat("%o", float(big), "123456__________________________", 6)
         # Some small ints, in both Python int and flavors).
         testformat("%d", 42, "42")
         testformat("%d", -42, "-42")
@@ -193,7 +195,8 @@
         testformat("%#x", 1, "0x1")
         testformat("%#X", 1, "0X1")
         testformat("%#X", 1, "0X1")
-        testformat("%#x", 1.0, "0x1")
+        with self.assertWarns(DeprecationWarning):
+            testformat("%#x", 1.0, "0x1")
         testformat("%#o", 1, "0o1")
         testformat("%#o", 1, "0o1")
         testformat("%#o", 0, "0o0")
@@ -210,12 +213,14 @@
         testformat("%x", -0x42, "-42")
         testformat("%x", 0x42, "42")
         testformat("%x", -0x42, "-42")
-        testformat("%x", float(0x42), "42")
+        with self.assertWarns(DeprecationWarning):
+            testformat("%x", float(0x42), "42")
         testformat("%o", 0o42, "42")
         testformat("%o", -0o42, "-42")
         testformat("%o", 0o42, "42")
         testformat("%o", -0o42, "-42")
-        testformat("%o", float(0o42), "42")
+        with self.assertWarns(DeprecationWarning):
+            testformat("%o", float(0o42), "42")
         testformat("%r", "\u0378", "'\\u0378'")  # non printable
         testformat("%a", "\u0378", "'\\u0378'")  # non printable
         testformat("%r", "\u0374", "'\u0374'")   # printable