Address review comments.

Author: serhiy-storchaka

Lib/test/test_bytes.py

@@ -799,7 +799,7 @@ def __int__(self):
         ]
 
         for msg, format_bytes, value in exceptions_params:
-            with self.assertRaisesRegex(TypeError, msg):
+            with self.assertRaisesRegex(TypeError, 'format argument: ' + msg):
                 operator.mod(format_bytes, value)
 
     def test_memory_leak_gh_140939(self):

Lib/test/test_str.py

@@ -1578,17 +1578,40 @@ def __int__(self):
         self.assertEqual('%X' % letter_m, '6D')
         self.assertEqual('%o' % letter_m, '155')
         self.assertEqual('%c' % letter_m, 'm')
-        self.assertRaisesRegex(TypeError, '%x requires an integer, not float', operator.mod, '%x', 3.14)
-        self.assertRaisesRegex(TypeError, '%X requires an integer, not float', operator.mod, '%X', 2.11)
-        self.assertRaisesRegex(TypeError, '%o requires an integer, not float', operator.mod, '%o', 1.79)
-        self.assertRaisesRegex(TypeError, r'%x requires an integer, not .*\.PseudoFloat', operator.mod, '%x', pi)
-        self.assertRaisesRegex(TypeError, '%x requires an integer, not complex', operator.mod, '%x', 3j)
-        self.assertRaisesRegex(TypeError, '%X requires an integer, not complex', operator.mod, '%X', 2j)
-        self.assertRaisesRegex(TypeError, '%o requires an integer, not complex', operator.mod, '%o', 1j)
-        self.assertRaisesRegex(TypeError, '%u requires a real number, not complex', operator.mod, '%u', 3j)
-        self.assertRaisesRegex(TypeError, '%i requires a real number, not complex', operator.mod, '%i', 2j)
-        self.assertRaisesRegex(TypeError, '%d requires a real number, not complex', operator.mod, '%d', 1j)
-        self.assertRaisesRegex(TypeError, r'%c requires an integer or a unicode character, not .*\.PseudoFloat', operator.mod, '%c', pi)
+        with self.assertRaisesRegex(TypeError,
+                'format argument: %x requires an integer, not float'):
+            '%x' % 3.14
+        with self.assertRaisesRegex(TypeError,
+                'format argument: %X requires an integer, not float'):
+            '%X' % 2.11
+        with self.assertRaisesRegex(TypeError,
+                'format argument: %o requires an integer, not float'):
+            '%o' % 1.79
+        with self.assertRaisesRegex(TypeError,
+                r'format argument: %x requires an integer, not .*\.PseudoFloat'):
+            '%x' % pi
+        with self.assertRaisesRegex(TypeError,
+                'format argument: %x requires an integer, not complex'):
+            '%x' % 3j
+        with self.assertRaisesRegex(TypeError,
+                'format argument: %X requires an integer, not complex'):
+            '%X' % 2j
+        with self.assertRaisesRegex(TypeError,
+                'format argument: %o requires an integer, not complex'):
+            '%o' % 1j
+        with self.assertRaisesRegex(TypeError,
+                'format argument: %u requires a real number, not complex'):
+            '%u' % 3j
+        with self.assertRaisesRegex(TypeError,
+                'format argument: %i requires a real number, not complex'):
+            '%i' % 2j
+        with self.assertRaisesRegex(TypeError,
+                'format argument: %d requires a real number, not complex'):
+            '%d' % 1j
+        with self.assertRaisesRegex(TypeError,
+                r'format argument: %c requires an integer or a unicode character, '
+                r'not .*\.PseudoFloat'):
+            '%c' % pi
 
         class RaisingNumber:
             def __int__(self):

Objects/unicode_format.c

@@ -77,6 +77,7 @@ struct unicode_format_arg_t {
 };
 
 
+// Use FORMAT_ERROR("...%s", "") when there is no arguments.
 #define FORMAT_ERROR(EXC, FMT, ...) do {                                    \
     if (arg->key != NULL) {                                                 \
         PyErr_Format((EXC), "format argument %R: " FMT,                     \