Added unittest dependency and fixed small typo.
Added unittest dependency and fixed small typo.

staats-google/webdriver.dart,bwu-dart-contributing/webdriver.dart,DrMarcII/webdriver.dart,bwu-dart-contributing/webdriver.dart,google/webdriver.dart,staats-google/webdriver.dart,DrMarcII/webdriver.dart,staats-google/webdriver.dart,bwu-dart-contributing/webdriver.dart,DrMarcII/webdriver.dart,staats-google/webdriver.dart,google/webdriver.dart,google/webdriver.dart,bwu-dart-contributing/webdriver.dart,DrMarcII/webdriver.dart