Imatest modules can analyze raw files directly, or after demosaicing.
Raw files can be read into Imatest in two main ways:
LibRaw: for standard (commercial) RAW formats (e.g. CR2, CR3, NEF, etc.)
For DNG files ONLY: There is an option to bypass LibRaw in the Options II settings window
Generalized Read Raw: for binary raw files created in engineering development systems, which are not supported by LibRaw.