1.放假回来，wda编译失败，报错如下
2018-09-25 10:03:09.020964+0800 WebDriverAgentRunner-Runner[335:33309] +[CATransaction synchronize] called within transaction
2018-09-25 10:03:09.147094+0800 WebDriverAgentRunner-Runner[335:33309] Running tests...
2018-09-25 10:03:12.911117+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding -[CAMLightingControl accessibilityLabel]
2018-09-25 10:03:12.911179+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding -[CAMLightingControl accessibilityValue]
2018-09-25 10:03:12.911213+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding -[CAMLightingControl accessibilityTraits]
2018-09-25 10:03:12.911253+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding -[CAMLightingControl isAccessibilityElement]
2018-09-25 10:03:12.911285+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding -[CAMLightingControl accessibilityIncrement]
2018-09-25 10:03:12.911319+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding -[CAMLightingControl accessibilityDecrement]
2018-09-25 10:03:12.911359+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding +[CAMLightingControl safeCategoryBaseClass]
2018-09-25 10:03:12.912923+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding -[PLManagedAsset accessibilityLabel]
2018-09-25 10:03:12.912959+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding -[PLManagedAsset accessibilityValue]
2018-09-25 10:03:12.912992+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding -[PLManagedAsset accessibilityTraits]
2018-09-25 10:03:12.913024+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding -[PLManagedAsset _accessibilityPhotoDescription]
2018-09-25 10:03:12.913056+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding +[PLManagedAsset safeCategoryBaseClass]
2018-09-25 10:03:12.940291+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding -[PHAsset accessibilityLabel]
2018-09-25 10:03:12.940354+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding -[PHAsset accessibilityValue]
2018-09-25 10:03:12.940387+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding -[PHAsset accessibilityTraits]
2018-09-25 10:03:12.940419+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding -[PHAsset _accessibilitySavePhotoLabel:]
2018-09-25 10:03:12.940465+0800 WebDriverAgentRunner-Runner[335:33309] [AXValidations] UIAccessibility Error adding +[PHAsset safeCategoryBaseClass]
Unexpected failure with no current test or suite:
Failed to perform device event <XCDeviceEvent:0x1d024cf00 page 12 usage 64 duration 0.01s: Error Domain=XCTDaemonErrorDomain Code=21 "Unable to perform <XCDeviceEvent:0x104701e80 page 12 usage 64 duration 0.01s, only one gesture can be performed at a time." UserInfo={NSLocalizedDescription=Unable to perform <XCDeviceEvent:0x104701e80 page 12 usage 64 duration 0.01s, only one gesture can be performed at a time.}
解决方式：重启手机。