bpo-34783: Add test_cmd_line_script.test_nonexisting_script() (pythonGH-9535)

Make sure that "./python script.py" does not crash if the script file doesn't exist.

Author: vstinner

Lib/test/test_cmd_line_script.py

@@ -630,6 +630,25 @@ def test_consistent_sys_path_for_module_execution(self):
  traceback_lines = stderr.decode().splitlines()
  self.assertIn("No module named script_pkg", traceback_lines[-1])
 
+ def test_nonexisting_script(self):
+ # bpo-34783: "./python script.py" must not crash
+ # if the script file doesn't exist.
+ script = 'nonexistingscript.py'
+ self.assertFalse(os.path.exists(script))
+ # Only test the base name, since the error message can use
+ # a relative path, whereas sys.executable can be an asolution path.
+ program = os.path.basename(sys.executable)
+
+ proc = spawn_python(script, text=True,
+ stdout=subprocess.PIPE,
+ stderr=subprocess.PIPE)
+ out, err = proc.communicate()
+ # "./python" must be in the error message:
+ # "./python: can't open file (...)"
+ self.assertIn(program, err)
+ self.assertNotEqual(proc.returncode, 0)
+
+
 def test_main():
  support.run_unittest(CmdLineTest)
  support.reap_children()