Integration test (cannot_read_files) fails when there is a file named "foo.txt" in working directory

[oSoMoN]

touch foo.txt
cargo test --release cannot_read_files

results in:

test cannot_read_files ... FAILED

failures:

---- cannot_read_files stdout ----
thread 'cannot_read_files' panicked at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/core/src/ops/function.rs:250:5:
Unexpected return code, failed var == 2
└── var: 0

command=`"/home/osomon/build/uutils/diffutils/target/release/diffutils" "foo.txt" "/tmp/.tmpwvzk9c"`
code=0
stdout=""

This is because the test expects a file named "foo.txt" to not exist in the current working directory. If the file exists, the test fails.