Hi Vijay,
I haven't look at this patchset directly, so here is how I would approach this one.
1. Look at the command line parameters of wusa.
2. Create the simplest MSU file as possible, with a directory and a file.
3. Pick "update /extract:" as first test
4. Check the files are extracted to where you think they should. 5. Cleanup.
(You can check how MSI does testing, wusa will be similar).
Alistair.