ActiveToSingleStates takes a map of active states (such as that returned by WaitForNActiveUnits) and ensures that each unit has at most a single active state.

CopyFile().

GenNewFleetService() is a helper for generating a temporary fleet service that reads from oldFile, replaces oldVal with newVal, and stores the result to newFile.

tempUnit creates a local unit file with the given contents, returning the name of the file.