`FileTestCase` in `test_lzma` can be improved

[sobolevn]

There are several tests that do not assert anything:

cpython/Lib/test/test_lzma.py

Lines 539 to 547 in 9649278

	def test_init(self):
	with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
	pass
	with LZMAFile(BytesIO(), "w") as f:
	pass
	with LZMAFile(BytesIO(), "x") as f:
	pass
	with LZMAFile(BytesIO(), "a") as f:
	pass

cpython/Lib/test/test_lzma.py

Lines 574 to 594 in 9649278

	def test_init_mode(self):
	with TempFile(TESTFN):
	with LZMAFile(TESTFN, "r"):
	pass
	with LZMAFile(TESTFN, "rb"):
	pass
	with LZMAFile(TESTFN, "w"):
	pass
	with LZMAFile(TESTFN, "wb"):
	pass
	with LZMAFile(TESTFN, "a"):
	pass
	with LZMAFile(TESTFN, "ab"):
	pass
	def test_init_with_x_mode(self):
	self.addCleanup(unlink, TESTFN)
	for mode in ("x", "xb"):
	unlink(TESTFN)
	with LZMAFile(TESTFN, mode) as f:
	pass

I propose to assert the context manager type and the mode.
I have a PR ready.

Linked PRs

• gh-131219: Improve tests in test_lzma.py by adding more asserts #131220
• [3.13] gh-131219: Improve tests in test_lzma.py by adding more asserts (GH-131220) #131231
• [3.12] gh-131219: Improve tests in test_lzma.py by adding more asserts (GH-131220) #131237