All the error cases for moving things are now consistent.
Split out the string-based file content read & write tests.
Starting to unify file read/write errors to use the same exception.
Starting to unify error results & tests for file reading.
Unify tests for writing to file in missing folder with either format.
One more consistent error report. clean exception types.
Finished splitting the low-level tests by purpose.
And now we have uniform error results for deleting stuff.