* Accept SFTP session in FS constructor;
* Modify Remote to build the session required by FS;
* Change TestEnvHelpers#build_remote in order to provided a test double
as the remote FS.
Allow use of our test environment, with a mocked remote and convenient
methods to write more concise expectations.
#env, builds and returns a memoized test environment (with mocked
remote)
#output, returns env output as a string
#remote_fs, returns env remote fs
#expect_execution, setup a remote command execution expectation