Tests for `pathlib.Path.walk()` are a little fragile

[barneygale]

test_walk_topdown() attempts to handle all possible visitation orders, but the result is difficult to read. We can enforce a specific order by sorting dirnames.

cpython/Lib/test/test_pathlib.py

Lines 2680 to 2694 in a6f9594

	def test_walk_topdown(self):
	all = list(self.walk_path.walk())
	self.assertEqual(len(all), 4)
	# We can't know which order SUB1 and SUB2 will appear in.
	# Not flipped: TESTFN, SUB1, SUB11, SUB2
	# flipped: TESTFN, SUB2, SUB1, SUB11
	flipped = all[0][1][0] != "SUB1"
	all[0][1].sort()
	all[3 - 2 * flipped][-1].sort()
	all[3 - 2 * flipped][1].sort()
	self.assertEqual(all[0], (self.walk_path, ["SUB1", "SUB2"], ["tmp1"]))
	self.assertEqual(all[1 + flipped], (self.sub1_path, ["SUB11"], ["tmp2"]))
	self.assertEqual(all[2 + flipped], (self.sub11_path, [], []))
	self.assertEqual(all[3 - 2 * flipped], self.sub2_tree)

test_walk_bottom_up() suffers similar problems, and also makes unjustified assertions about the order that siblings are visited (which is arbitrary and cannot be influenced by the user, contrary to top-down mode). It can be simplified to ensure that children are yielded before parents.

cpython/Lib/test/test_pathlib.py

Lines 2717 to 2735 in a6f9594

	def test_walk_bottom_up(self):
	all = list(self.walk_path.walk( top_down=False))
	self.assertEqual(len(all), 4, all)
	# We can't know which order SUB1 and SUB2 will appear in.
	# Not flipped: SUB11, SUB1, SUB2, TESTFN
	# flipped: SUB2, SUB11, SUB1, TESTFN
	flipped = all[3][1][0] != "SUB1"
	all[3][1].sort()
	all[2 - 2 * flipped][-1].sort()
	all[2 - 2 * flipped][1].sort()
	self.assertEqual(all[3],
	(self.walk_path, ["SUB1", "SUB2"], ["tmp1"]))
	self.assertEqual(all[flipped],
	(self.sub11_path, [], []))
	self.assertEqual(all[flipped + 1],
	(self.sub1_path, ["SUB11"], ["tmp2"]))
	self.assertEqual(all[2 - 2 * flipped],
	self.sub2_tree)

Linked PRs

• GH-103517: Improve tests for pathlib.Path.walk() #103518

[barneygale]

Resolved by #103518.