Add unit tests that check compressing->decompressing a file should
result in the same file. This is done by comparing the CRC32
before and after. The same tests also implicitly test that
compression/decompression works by checking the return
value of ZCodec::EndCompression.
Cases added for both mbGzLib=true/false.
Change-Id: I5516760eba5f233c20331cef83fd0b1a1603373f
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/135233
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>
