Add missing iterations in tests

[sosthene-nitrokey]

The tests don't actually test every file.
The iteration skips the two . and .. directories, which means that the last two files were not read. This PR fixes that. This seems to reach an edge case reported in #785.

As can be seen, the tests fail at a call to lfs_dir_seek, when they shouldn't.

[geky]

Hi @sosthene-nitrokey, thanks for creating an issue.

I'm trying to dig into the bug, but I'm not sure this test was actually missing files?

It's a bit convoluted, but the lfs_dir_reads at the beginning of the loop should be skipping the . and .. entries before the inner loop iterates over directory entries from 0 to j.

littlefs/tests/test_dirs.toml

Lines 790 to 814 in 6a53d76

	for (int j = 2; j < COUNT; j++) {
	lfs_mount(&lfs, &cfg) => 0;
	lfs_dir_open(&lfs, &dir, "/") => 0;
	lfs_dir_read(&lfs, &dir, &info) => 1;
	assert(strcmp(info.name, ".") == 0);
	assert(info.type == LFS_TYPE_DIR);
	lfs_dir_read(&lfs, &dir, &info) => 1;
	assert(strcmp(info.name, "..") == 0);
	assert(info.type == LFS_TYPE_DIR);
	lfs_soff_t pos;
	for (int i = 0; i < j; i++) {
	sprintf(path, "hi%03d", i);
	lfs_dir_read(&lfs, &dir, &info) => 1;
	assert(strcmp(info.name, path) == 0);
	assert(info.type == LFS_TYPE_DIR);
	pos = lfs_dir_tell(&lfs, &dir);
	assert(pos >= 0);
	}
	lfs_dir_seek(&lfs, &dir, pos) => 0;
	sprintf(path, "hi%03d", j);
	lfs_dir_read(&lfs, &dir, &info) => 1;
	assert(strcmp(info.name, path) == 0);
	assert(info.type == LFS_TYPE_DIR);

Correct me if I'm wrong. I'll look into the error it's throwing.

[geky]

Ah, the issue is it should be i <= j, so this does show this did hide the directory bug.

[geky]

Well, no, the i < j iterates the all previous entries, the final lfs_dir_tell should hold the correct pos.

The j = 2 is incorrect in the loop though, so we are missing the first two entries. Though this doesn't reveal the underlying bug.

I think this needs its own test.

[geky]

I went ahead and created #805, thanks for creating a PR!

[sosthene-nitrokey]

Thank you for the investigation and the fix!

Feel free to close this PR as your PR also adds tests that cover this. This PR was meant mostly as an example reproducer, and not really with the goal to be merged.