Structure tests according to methods
Fix typo
Add method to create directory from given data
Be more safe regarding newlines at end of file
Make clashes with user variables more unlikely
Rename @path to @path_elements
Add option to keep test files around
Make methods private which are not part of API
Factor out creation of random base path
Extract check for existence of base path
Rename path_has_base to path_has_base?
Separate creation of base path and unnamed directories

All given filesystems are created under a random base path now.
This adds one more level of nesting, but gives a clean consistent
state for all cases of named and unnamed directories and files.

This also fixes the bug that nested unnamed directories weren't
created.
Make names with included directories work

Names passed to given_file and given_directory can contain path
elements, e.g.

  given_directory( "a/b/c" )

or

  given_file( "a/b/c.txt" )

The required directories are created as needed.
Add process id to random name of generated files

This makes it even less likely to have collisions and also gives
a way to tell, which files were created in which run of the tests.
Ignore rspec default parameter file