python
diff --git a/‎Lib/test/test_faulthandler.py
Copy file name to clipboardExpand all lines: Lib/test/test_faulthandler.py
+40-5Lines changed: 40 additions & 5 deletions b/‎Lib/test/test_faulthandler.py
Copy file name to clipboardExpand all lines: Lib/test/test_faulthandler.py
+40-5Lines changed: 40 additions & 5 deletions
@@ -45,6 +45,13 @@ def temporary_filename():
     finally:
         os_helper.unlink(filename)
 
+
+ADDRESS_EXPR = "0x[0-9a-f]+"
+C_STACK_REGEX = [
+    r"Current thread's C stack trace \(most recent call first\):",
+    fr"  ((\/.+)+\(.*\+{ADDRESS_EXPR}\) \[{ADDRESS_EXPR}\])|(<.+>)"
+]
+
 class FaultHandlerTests(unittest.TestCase):
 
     def get_output(self, code, filename=None, fd=None):
@@ -101,16 +108,15 @@ def check_error(self, code, lineno, fatal_error, *,
 
         Raise an error if the output doesn't match the expected format.
         """
-        address_expr = "0x[0-9a-f]+"
         all_threads_disabled = (
             all_threads
             and (not sys._is_gil_enabled())
         )
         if all_threads and not all_threads_disabled:
             if know_current_thread:
-                header = f'Current thread {address_expr}'
+                header = f'Current thread {ADDRESS_EXPR}'
             else:
-                header = f'Thread {address_expr}'
+                header = f'Thread {ADDRESS_EXPR}'
         else:
             header = 'Stack'
         regex = [f'^{fatal_error}']
@@ -129,8 +135,7 @@ def check_error(self, code, lineno, fatal_error, *,
                 regex.append('  Garbage-collecting')
             regex.append(fr'  File "<string>", line {lineno} in {function}')
         if c_stack:
-            regex.append("Current thread's C stack (most recent call first):")
-            regex.append(fr"  (\/.+\(\+.+\) \[{address_expr}\])|(<.+>)")
+            regex.extend(C_STACK_REGEX)
         regex = '\n'.join(regex)
 
         if other_regex:
@@ -941,5 +946,35 @@ def run(self):
         _, exitcode = self.get_output(code)
         self.assertEqual(exitcode, 0)
 
+    def check_c_stack(self, output):
+        starting_line = output.pop(0)
+        self.assertRegex(starting_line, C_STACK_REGEX[0])
+        self.assertGreater(len(output), 0)
+
+        for line in output:
+            with self.subTest(line=line):
+                if line != '':  # Ignore trailing or leading newlines
+                    self.assertRegex(line, C_STACK_REGEX[1])
+
+
+    def test_dump_c_stack(self):
+        code = dedent("""
+        import faulthandler
+        faulthandler.dump_c_stack()
+        """)
+        output, exitcode = self.get_output(code)
+        self.assertEqual(exitcode, 0)
+        self.check_c_stack(output)
+
+
+    def test_dump_c_stack_file(self):
+        import tempfile
+
+        with tempfile.TemporaryFile("w+") as tmp:
+            faulthandler.dump_c_stack(file=tmp)
+            tmp.flush()  # Just in case
+            tmp.seek(0)
+            self.check_c_stack(tmp.read().split("\n"))
+
 if __name__ == "__main__":
     unittest.main()