gh-115773: Add tests to exercise the _Py_DebugOffsets structure (#115774)

1 files changed, 84 insertions, 0 deletions

diff --git a/Lib/test/test_external_inspection.py b/Lib/test/test_external_inspection.py
new file mode 100644
index 0000000..86c07de
--- /dev/null
+++ b/Lib/test/test_external_inspection.py
@@ -0,0 +1,84 @@
+import unittest
+import os
+import textwrap
+import importlib
+import sys
+from test.support import os_helper, SHORT_TIMEOUT
+from test.support.script_helper import make_script
+
+import subprocess
+
+PROCESS_VM_READV_SUPPORTED = False
+
+try:
+    from _testexternalinspection import PROCESS_VM_READV_SUPPORTED
+    from _testexternalinspection import get_stack_trace
+except ImportError:
+    unittest.skip("Test only runs when _testexternalinspection is available")
+
+def _make_test_script(script_dir, script_basename, source):
+    to_return = make_script(script_dir, script_basename, source)
+    importlib.invalidate_caches()
+    return to_return
+
+class TestGetStackTrace(unittest.TestCase):
+
+    @unittest.skipIf(sys.platform != "darwin" and sys.platform != "linux", "Test only runs on Linux and MacOS")
+    @unittest.skipIf(sys.platform == "linux" and not PROCESS_VM_READV_SUPPORTED, "Test only runs on Linux with process_vm_readv support")
+    def test_remote_stack_trace(self):
+        # Spawn a process with some realistic Python code
+        script = textwrap.dedent("""\
+            import time, sys, os
+            def bar():
+                for x in range(100):
+                    if x == 50:
+                        baz()
+            def baz():
+                foo()
+
+            def foo():
+                fifo = sys.argv[1]
+                with open(sys.argv[1], "w") as fifo:
+                    fifo.write("ready")
+                time.sleep(1000)
+
+            bar()
+            """)
+        stack_trace = None
+        with os_helper.temp_dir() as work_dir:
+            script_dir = os.path.join(work_dir, "script_pkg")
+            os.mkdir(script_dir)
+            fifo = f"{work_dir}/the_fifo"
+            os.mkfifo(fifo)
+            script_name = _make_test_script(script_dir, 'script', script)
+            try:
+                p = subprocess.Popen([sys.executable, script_name,  str(fifo)])
+                with open(fifo, "r") as fifo_file:
+                    response = fifo_file.read()
+                self.assertEqual(response, "ready")
+                stack_trace = get_stack_trace(p.pid)
+            except PermissionError:
+                self.skipTest("Insufficient permissions to read the stack trace")
+            finally:
+                os.remove(fifo)
+                p.kill()
+                p.terminate()
+                p.wait(timeout=SHORT_TIMEOUT)
+
+
+            expected_stack_trace = [
+                'foo',
+                'baz',
+                'bar',
+                '<module>'
+            ]
+            self.assertEqual(stack_trace, expected_stack_trace)
+
+    @unittest.skipIf(sys.platform != "darwin" and sys.platform != "linux", "Test only runs on Linux and MacOS")
+    @unittest.skipIf(sys.platform == "linux" and not PROCESS_VM_READV_SUPPORTED, "Test only runs on Linux with process_vm_readv support")
+    def test_self_trace(self):
+        stack_trace = get_stack_trace(os.getpid())
+        self.assertEqual(stack_trace[0], "test_self_trace")
+
+if __name__ == "__main__":
+    unittest.main()