[3.14] gh-71339: Use new assertion methods in tests (GH-129046) (GH-134498)

(cherry picked from commit 2602d8ae981c4bae1cada2c174b367d97f712efb)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/Lib/test/test_cmd_line.py b/Lib/test/test_cmd_line.py
index f540973..c17d749 100644
--- a/Lib/test/test_cmd_line.py
+++ b/Lib/test/test_cmd_line.py
@@ -39,7 +39,8 @@ class CmdLineTest(unittest.TestCase):
 
     def verify_valid_flag(self, cmd_line):
         rc, out, err = assert_python_ok(cmd_line)
-        self.assertTrue(out == b'' or out.endswith(b'\n'))
+        if out != b'':
+            self.assertEndsWith(out, b'\n')
         self.assertNotIn(b'Traceback', out)
         self.assertNotIn(b'Traceback', err)
         return out
@@ -89,8 +90,8 @@ class CmdLineTest(unittest.TestCase):
         version = ('Python %d.%d' % sys.version_info[:2]).encode("ascii")
         for switch in '-V', '--version', '-VV':
             rc, out, err = assert_python_ok(switch)
-            self.assertFalse(err.startswith(version))
-            self.assertTrue(out.startswith(version))
+            self.assertNotStartsWith(err, version)
+            self.assertStartsWith(out, version)
 
     def test_verbose(self):
         # -v causes imports to write to stderr.  If the write to
@@ -380,7 +381,7 @@ class CmdLineTest(unittest.TestCase):
         p.stdin.flush()
         data, rc = _kill_python_and_exit_code(p)
         self.assertEqual(rc, 0)
-        self.assertTrue(data.startswith(b'x'), data)
+        self.assertStartsWith(data, b'x')
 
     def test_large_PYTHONPATH(self):
         path1 = "ABCDE" * 100
@@ -1039,7 +1040,7 @@ class CmdLineTest(unittest.TestCase):
                               stderr=subprocess.PIPE,
                               text=True)
         err_msg = "Unknown option: --unknown-option\nusage: "
-        self.assertTrue(proc.stderr.startswith(err_msg), proc.stderr)
+        self.assertStartsWith(proc.stderr, err_msg)
         self.assertNotEqual(proc.returncode, 0)
 
     def test_int_max_str_digits(self):