实践 UI Testing in Xcode

blog:

comment:

　1. wait-for-idle

view 与view 之间转换的时候，为了保证有效的manipulation 和assertion，等待app处于稳定的状态再执行操作

  _ = self.expectationForPredicate(
            NSPredicate(format: "self.count = 1"),
            evaluatedWithObject: XCUIApplication().tables,
            handler: nil)
  self.waitForExpectationsWithTimeout(5.0, handler: nil)

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