$ cargo test

$ cargo +nightly bench --features=nightly
running 5 tests
test tests::test_check_pow_invalid ... ignored
test tests::test_check_pow_valid ... ignored
test tests::test_pow_hash ... ignored
test tests::bench_pow_hash  ... bench:         411 ns/iter (+/- 92)
test tests::bench_pow_valid ... bench:       1,459 ns/iter (+/- 223)
test result: ok. 0 passed; 0 failed; 3 ignored; 2 measured; 0 filtered out
$