[Dev] Unit test for tempfile alters test file in place

[DanielYang59]

Unit test for tempfile (test_tempfile.py) alters test file 3000_lines.txt.gz in place (because of re-gzip), could leadi to repeated commit of this file, for example in fd6b16d.

Triggered by the following test:

monty/tests/test_tempfile.py

Lines 47 to 66 in 09d3692

	def test_with_copy_gzip(self):
	# We write a pre-scratch file.
	with open("pre_scratch_text", "w") as f:
	f.write("write")
	init_gz = [f for f in os.listdir(os.getcwd()) if f.endswith(".gz")]
	with ScratchDir(
	self.scratch_root,
	copy_from_current_on_enter=True,
	copy_to_current_on_exit=True,
	gzip_on_exit=True,
	), open("scratch_text", "w") as f:
	f.write("write")
	files = os.listdir(os.getcwd())
	# Make sure the stratch_text.gz exists
	assert "scratch_text.gz" in files
	for f in files:
	if f.endswith(".gz") and f not in init_gz:
	os.remove(f)
	os.remove("pre_scratch_text")