docstr: Test PyUnicode_Format()
docstr_tok: ["Test","PyUnicode_Format","(",")"]
code: def test_format(self):
      """Test PyUnicode_Format()"""
      from _testcapi import unicode_format as format
  
      self.assertEqual(format("x=%d!", 42), "x=42!")
      self.assertEqual(format("x=%d!", (42,)), "x=42!")
      self.assertEqual(format("x=%d y=%s!", (42, [])), "x=42 y=[]!")
  
      self.assertRaises(SystemError, format, "x=%d!", NULL)
      self.assertRaises(SystemError, format, NULL, 42)
  
imports: import unittest
  import sys
  from test import support
  from test.support import import_helper
label_desc: Use image node_id 45 for calling the CAPITest obj's underlying member method code with example usage: obj.test_format() without return types