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How can i test a Delegates.Observable that is inside a BroadcastReceiver. I need to get battery level of device and check if it's just went below or above pre-defined critical level, and upload to server using UseCase of clean architecture. I used observable to observe only changing states.

private fun handleIntent(context: Context, intent: Intent) {

    when (intent.action) {

 

        Intent.ACTION_BATTERY_CHANGED -> {

            try {
                val batteryStatus =
                    context.registerReceiver(null, IntentFilter(Intent.ACTION_BATTERY_CHANGED))
                val level = batteryStatus?.getIntExtra(BatteryManager.EXTRA_LEVEL, -1) ?: -1
                val scale = batteryStatus?.getIntExtra(BatteryManager.EXTRA_SCALE, -1) ?: -1

                 batteryPct = (level / scale.toFloat() * 100).toInt()

                isBatteryBelowCritical = batteryPct > CRITICAL_BATTERY

            } catch (e: Exception) {

            }

        }
    }
}

And observable

private var isBatteryBelowCritical by Delegates.observable(false) { _, old, new ->

        //has gone above critical battery value
        if (old && !new) {
            sendAlarmUseCase.sendBatteryAlarm(batteryPct)
        } else if (!old && new) {
            // has gone below critical battery value
            sendAlarmUseCase.sendBatteryAlarm(batteryPct)
        }

    }

Do i have to use parameters or assume old value to test current value? How is state is tested? Should i use parameterized test or assume previous value?

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1 回答 1

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您可以使用一种依赖注入并重构检查状态更改的逻辑：

fun notifyOnlyOnChange(initialValue: Boolean, notify: () -> Unit): ReadWriteProperty<Any?, Boolean> =
    Delegates.observable(initialValue) { _, old, new ->
        if (old != new) // your logic can be simplified to this
            notify()
    }

然后你可以像这样在 BroadcastReceiver 中使用它：

private var isBatteryBelowCritical by notifyOnlyOnChange(false) { 
    sendAlarmUseCase.sendBatteryAlarm(batteryPct)
}

并像这样对它进行单元测试：


@Test
fun `test observers are not notified when value is not changed`() {
    var observable1 by notifyOnlyOnChange(false) { fail() }
    observable1 = false
    var observable2 by notifyOnlyOnChange(true) { fail() }
    observable2 = true
}

@Test
fun `test observers are notified when value is changed`() {
    var notified1 = false
    var observable1 by notifyOnlyOnChange(false) { notified1 = true }
    observable1 = true
    assertTrue(notified1)
    var notified2 = false
    var observable2 by notifyOnlyOnChange(true) { notified2 = true }
    observable2 = false
    assertTrue(notified2)
}
于 2020-11-08T23:53:56.950 回答