An IdlingResource and a TestRule that keep espresso busy while at least one view matches a Matcher<View>

Sometimes it's too hard or complicated to set up IdlingResources to let espresso know when your app is busy. In a lot of those cases there may also be a visual indicator on screen. You can use this library to mark the presence of the indicator as a hint that espresso should wait.

That indicator can be whatever view or hierarchy you want as long as you can describe it as a Matcher<View>

In your root build.gradle file:

allprojects {
    repositories {
        //...
        maven { url 'https://jitpack.io' }
    }
}

In your app build.gradle file:

dependencies {
    //...
    androidTestImplementation "com.github.mirceanis:view-matching-idler:0.1"
}

It can be used as a TestRule or, if you want more granular control over it, as an IdlingResource

Here's an example that makes espresso wait as long as the "loading" text is visible:

    //simply declare it in your test class:
    @get:Rule
    val viewMatcherIdlingRule = ViewMatcherIdlingRule(
        //be sure to customize the blocking view matcher based on your case
        allOf(withText("loading"), isDisplayed())
    )
    
    @Test
    fun myFancyTest() {
        //normal espresso testing, but espresso will wait while the view matcher condition is met
    }

Here's an example that makes espresso wait as long as the "loading" text is visible:

    @Test
    fun someTestMethod() {
    
        //... some testing

        //This will keep espresso busy while at least one view matches this matcher
        val idler = ViewMatcherIdler(allOf(withText("loading"), isDisplayed()))
        IdlingRegistry.getInstance().register(idler)

        //... some more testing, but now espresso waits
        //... during the times the matcher from above matches a view

        IdlingRegistry.getInstance().unregister(idler)
    }

Check out the sample app included in this repo for a practical example.

The best way to contribute to this is to use it and find issues. PRs welcome.

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