test: use mtime for -ot and fix direction of comparison

[n1000]

• Use the file modification time instead of the creation time (matches GNU coreutils documentation)

• Fix direction of comparison (a < b instead of a > b)

• Extend test case to cover both the 0 and 1 exit code cases

[n1000]

Here is the specific coreutils documentation page I was referring to.

I wasn't sure how to test on android, so left the #cfg check in place for that target environment. For musl testing I used cargo test --target=x86_64-unknown-linux-musl test_test.

[sylvestre]

Looks good :)
I am curious how you found this issue :)

[n1000]

I am curious how you found this issue :)

I ended up finding this issue while running the tests on OpenBSD and digging into why this test case was failing. Eventually I found out OpenBSD was providing creation times of "0".. This led me to checking the OpenBSD "test" implementation and finding out that there both -nt and -ot used mtime.

Once I changed the uutils/coreutils "-ot" implementation to use the modified time, it was easier to spot that the -nt implementation on the line above was identical to "-ot" which raised a red flag.. 😃