pub fn build_mock_data(size: usize) -> Vec<u8> ⓘExpand description
Build a deterministic byte array for mock testing.
The payload is a xorshift64 keystream, which has no short period: distinct
equal-length windows of the result differ. This matters because the usual
end-to-end check is assert_eq!(downloaded, build_mock_data(size)), and a
periodic payload makes that assertion blind to whole blocks written at the wrong
offset or swapped between workers.
The result is prefix-stable: build_mock_data(n) is the first n bytes of
build_mock_data(m) for every m >= n, so a range of the full array can be used
as the expected value for a partial download.