IssueTracker

Looking at using the Compose Preview Screenshot functionality, a limitation that might block me adopting is the lack of interaction testing.

While this is by design, the actual common usecase is fairly minimal. And potentially would be a useful preview feature.

Example

https://github.com/joreilly/Confetti/blob/main/wearApp/src/test/kotlin/dev/johnoreilly/confetti/wear/SpeakerDetailsTest.kt#L24

    @Test
    fun speakerDetailsScreen() {
        composeRule.setContent {
            TestScaffold {
                SpeakerDetailsView(
                    uiState = SpeakerDetailsUiState.Success(JohnOreilly.speakerDetails),
                )
            }
        }
        composeRule.onNodeWithText("John O'Reilly").assertIsDisplayed()

        // screenshot at top
        takeScreenshot()

        // scroll to the end
        composeRule.onNode(hasScrollToIndexAction())
          .performTouchInput {
            repeat(10) {
                swipeUp(durationMillis = 10)
            }
          }

        // screenshot at end
        takeScreenshot("_end")
    }

Feature request

• Previews and therefore Preview Screenshot testing for Lists, Columns etc
• One of:
  • Limited Interactions to move the list in some way
  • Maybe - support for long screenshots instead?
  • A preview annotation for capturing different positions in a list?

The workaround is to hoist the List State out of the composable, however this has some downsides. For Wear, the ScalingLazyColumn state may include some calculated values for initial position, and so the preview would duplicate this logic.

This overall feature is critical on Wear given that clipping of content at the top or bottom of the screen is enough to reject an app from the Play Store review.