No matter how much careful we are when writing code, whatever changes we are making to a piece of software we must test them before production, even Donald Knuth once said:
Beware of bugs in the above code; I have only proved it correct, not tried it. :).
Moreover, if the software we are working on is targeting an embedded system and needs cross-compilation and depends on other software, then testing can be more tedious: we have to prepare patches/archives and instruct the target SDK to pick our latest code, or we could code directly in the SDK working tree, but that would not be very clean. If you use git and OpenEmbedded there is a very neat way to build directly from our own working directory on the filesystem.