Kaspresso. How check element is displayed without exception

Question

I want check authauthorization screen is displayed with kaspresso But isDisplyed() dont return boolean, and i have error.

How check element is displayed without exception

Now my solution:

fun isNeedAuth(): Boolean {
        return try {
            authButton.isEnabled()
            true
        } catch (e: NullPointerException) {
            false
        }
    }

Answer 1

I'm personally using:

fun safeAssertion(assert: () -> Unit) =
    try {
        assert()
        true
    } catch (_: Throwable) {
        false
    }

In tests it looks like:

if (safeAssertion { authButton.isEnabled() }) { doSomething() }

Also, you can make an extension for KViews:

fun <K : BaseAssertions> K.safeAssert(assert: K.() -> Unit) = safeAssertion { assert() }

And use it like:

if (authButton.safeAssert { isDisplayed() }) { doSomething() }

More advanced solution with waiting for desired state:

fun waitUntilConditionMet(
    description: String = "",
    maxWaitTime: Duration = 10.seconds,
    retryInterval: Duration = 250.milliseconds,
    onFail: () -> Unit = { throw MyCustomWaitingFailedException(maxWaitTime, description) },
    conditionToMeet: () -> Boolean
) {
    try {
        runBlocking {
            withTimeout(maxWaitTime) {
                while (!conditionToMeet()) {
                    delay(retryInterval)
                }
            }
        }
    } catch (e: Throwable) {
        Log.e("My Custom Waiter", e.message ?: "Failed to meet condition in ${maxWaitTime.inWholeSeconds} seconds")
        onFail()
    }
}

Usage example (will throw exception if condition is not met in 10 seconds):

waitUntilConditionMet("Some screen appeared") {
    safeAssertion {
        someButton.isDisplayed()
        anotherView.isEnabled()
    }
}

Or without throwing exception:

waitUntilConditionMet(
    description = "Some screen appeared",
    onFail = { doSomethingIfConditionIsNotMet() }
) {
    safeAssertion {
        someButton.isDisplayed()
        anotherView.isEnabled()
    }
}