fn mismatch_dir(tier: Option<&str>) -> Result<PathBuf, String>Expand description
Where the mismatched frames of a tier are collected, relative to the workspace root.
An absolute path is passed to the tests because they run with their own package as the working directory, so a relative one would put each package’s frames somewhere different. Collecting them in one directory is what lets CI upload every frame that failed from a single path.