commonMain.androidx.compose.ui.test.IdlingResource.kt Maven / Gradle / Ivy
/*
* Copyright 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.compose.ui.test
/**
* Represents a resource of an application under test which can cause asynchronous background
* work to happen during test execution (e.g. an http request in response to a button click).
*
* By default, all interactions from the test with the compose tree (finding nodes, performing
* gestures, making assertions) will be synchronized with pending work in Compose's internals
* (such as applying state changes, recomposing, measuring, etc). This ensures that the UI is in
* a stable state when the interactions are performed, so that e.g. no pending recompositions are
* still scheduled that could potentially change the UI. However, any asynchronous work that is
* not done through one of Compose's mechanisms won't be included in the default synchronization.
* For such work, test authors can create an [IdlingResource] and register it into the test with
* [registerIdlingResource][androidx.compose.ui.test.junit4.ComposeTestRule
* .registerIdlingResource], and the interaction will wait for that resource to become idle prior
* to performing it.
*/
interface IdlingResource {
/**
* Whether or not the [IdlingResource] is idle when reading this value. This should always be
* called from the main thread, which is why it should be lightweight and fast.
*
* If one idling resource returns `false`, the synchronization system will keep polling all
* idling resources until they are all idle.
*/
val isIdleNow: Boolean
/**
* Returns diagnostics that explain why the idling resource is busy, or `null` if the
* resource is not busy. Default implementation returns `null`.
*/
fun getDiagnosticMessageIfBusy(): String? = null
}