SCSI Test tests filing systems by writing and reading blocks of memory.
One of the fun things that happens as a software writer is people come to you and say "my life's work is in this document and your software says it is corrupt". one then spends a few hours trying to fix a damaged file. Usually the fault is with the application but sometimes it is the file system. Eventually I wrote this tester, and at the time it revealed bugs in file systems. However about that time vendors of file systems decided to concentrate more on reliability and less on speed. It was probably the point where basic file system speeds became faster than the RISC OS hardware could go.
It has not been quite as popular as it should have been.