Check for GNU Diff when using a TFS repository.
Review Request #7615 — Created Sept. 3, 2015 and submitted
Now that TFS requires GNU diff, we need to make sure that it's installed, and present a helpful error message if it's not. We already do this for a number of other SCMClients, like SVN and Perforce, and have a handy utility method for this. This uses that method to do the check and print the appropriate information.
Set my path so that GNU diff could not be found but a fake tfs could.
Posted a change and saw the error. Added GNU diff to the path, and saw
it got past the check.