Adding simple error handling to mode-test.
Adding simple error handling to mode-test.

mpapp/google-diff-match-patch-Objective-C,JanX2/google-diff-match-patch-Objective-C,JanX2/google-diff-match-patch-Objective-C,mpapp/google-diff-match-patch-Objective-C,mpapp/google-diff-match-patch-Objective-C,JanX2/google-diff-match-patch-Objective-C