android / android/android-test
Espresso's `ViewActions.click()` appears to be flaky
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- Java
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Description
### Description
I recently switched a test suite from API 30 to API 34 devices and I'm witnessing occasional fails (roughly 1 in 5 times across ~300 tests) in tests where we click (via `onView(withText("blah")).perform(click())`) on something and then expect to see the next screen. Inspecting video recordings for these (I'm using Firebase Testlab), I routinely see that the click has never occurred. I've seen this across multiple parts of a large app, so I'm fairly confident this is a problem in the test code rather than some race condition in the application code.
I had wondered if this was `click()` being executed before `setOnClickListener` in some circumstances, but as far as I can tell (through some hacky logging and exception throwing) this isn't the case and Espresso is waiting for the Activity/Fragment lifecycle to complete before interacting (as expected).
My suspicion is that there is some flakiness in `click()` itself and this seems to be more present in API 34 than it was in earlier versions.
I've tried a couple of different solutions to this that all seem to remove the flakes:
1. Using a "try again" mechanism that makes the click, waits for the result it expects, and then tries the click again if it doesn't get it. This is very common in other UI testing frameworks, but not something I've generally had to resort to in Espresso (due to the `IdlingResource` system).
2. Building a custom `OnClickListener` that can "signal" the tests when the click has actually occurred. Combining this with a "try again" approach allows your code to be certain that the click event has propagated (rather than needing to wait on some change in the view), but is obviously very invasive (we're changing application code to accommodate tests).
3. Using a custom `ViewAction` that calls `performClick()` on the `View` instead of attempting to inject a tap. This feels like a glaringly simple solution, but it doesn't work with all views. For example, a `TextView` might be the child of a clickable view rather than clickable itself (like in the case of a view pager title for instance). My guess is that cases like this were the reason (or at least one of the reasons) for building out `ViewActions.click()` to inject an event in the first place.
### Steps to Reproduce
With a view that contains a button that changes screen/alters the view:
```kotlin
onView(withText("button test")).perform(click())
onView(withText("something new after the button click")).matches(isDisplayed())
```
### Expected Results
Espresso will always successfully click on the button.
### Actual Results
The click sometimes doesn't happen.
### AndroidX Test and Android OS Versions
Espresso 3.5.1 and API 34 running mainly on `MediumPhone.arm` virtual device on Firebase Test Lab.
Contributor guide
Research direction
Start by repeatedly running the provided onView(withText("button test")).perform(click()) reproduction on Espresso 3.5.1 and API 34, comparing it with earlier API levels if available. Inspect the click behavior around the reported missed interaction; done means the reproduction reliably reaches "something new after the button click" or the limitation and cause are clearly documented.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- android, kotlin
- Domain
- mobile, testing
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 38/100