bpo-34228: Allow PYTHONTRACEMALLOC=0 (GH-8467)

PYTHONTRACEMALLOC=0 environment variable and -X tracemalloc=0 command
line option are now allowed to disable explicitly tracemalloc at
startup.

1 files changed, 10 insertions, 2 deletions

diff --git a/Lib/test/test_tracemalloc.py b/Lib/test/test_tracemalloc.py
index b0a0e1b..491cd05 100644
--- a/Lib/test/test_tracemalloc.py
+++ b/Lib/test/test_tracemalloc.py
@@ -15,6 +15,7 @@ except ImportError:
 
 
 EMPTY_STRING_SIZE = sys.getsizeof(b'')
+INVALID_NFRAME = (-1, 2**30)
 
 
 def get_frames(nframe, lineno_delta):
@@ -833,6 +834,13 @@ class TestCommandLine(unittest.TestCase):
         stdout = stdout.rstrip()
         self.assertEqual(stdout, b'False')
 
+    def test_env_var_disabled(self):
+        # tracing at startup
+        code = 'import tracemalloc; print(tracemalloc.is_tracing())'
+        ok, stdout, stderr = assert_python_ok('-c', code, PYTHONTRACEMALLOC='0')
+        stdout = stdout.rstrip()
+        self.assertEqual(stdout, b'False')
+
     def test_env_var_enabled_at_startup(self):
         # tracing at startup
         code = 'import tracemalloc; print(tracemalloc.is_tracing())'
@@ -861,7 +869,7 @@ class TestCommandLine(unittest.TestCase):
 
 
     def test_env_var_invalid(self):
-        for nframe in (-1, 0, 2**30):
+        for nframe in INVALID_NFRAME:
             with self.subTest(nframe=nframe):
                 self.check_env_var_invalid(nframe)
 
@@ -889,7 +897,7 @@ class TestCommandLine(unittest.TestCase):
         self.fail(f"unexpeced output: {stderr!a}")
 
     def test_sys_xoptions_invalid(self):
-        for nframe in (-1, 0, 2**30):
+        for nframe in INVALID_NFRAME:
             with self.subTest(nframe=nframe):
                 self.check_sys_xoptions_invalid(nframe)