NPE in SnapshotVerifier during tests

[luizgrp]

Most of the tests are failing in CI with:

java.lang.NullPointerException: goldenImage must not be null
	at app.cash.paparazzi.SnapshotVerifier$newFrameHandler$1.handle(SnapshotVerifier.kt:53)
	at com.google.android.horologist.paparazzi.WearSnapshotHandler$newFrameHandler$1.handle(WearSnapshotHandler.kt:57)
	at app.cash.paparazzi.Paparazzi$takeSnapshots$1$2.invoke(Paparazzi.kt:302)
	at app.cash.paparazzi.Paparazzi$takeSnapshots$1$2.invoke(Paparazzi.kt:295)
	at app.cash.paparazzi.Paparazzi.withTime(Paparazzi.kt:336)
	at app.cash.paparazzi.Paparazzi.takeSnapshots(Paparazzi.kt:295)
	at app.cash.paparazzi.Paparazzi.snapshot(Paparazzi.kt:211)
	at app.cash.paparazzi.Paparazzi.snapshot(Paparazzi.kt:204)
	at app.cash.paparazzi.Paparazzi.snapshot$default(Paparazzi.kt:195)
	at com.google.android.horologist.media.ui.FigmaVolumeScreenTest.volumePlayerScreen(FigmaVolumeScreenTest.kt:46)

The stacktrace above can be seen in the test reports in the archived artifact. In the actions logs it displays the following:

com.google.android.horologist.media.ui.FigmaVolumeScreenTest > volumePlayerScreen FAILED
    java.lang.NullPointerException at FigmaVolumeScreenTest.kt:46

...

53 tests completed, 35 failed
> Task :media-ui:testDebugUnitTest FAILED

Some investigation reported here.

Usage of WearSnapshotHandler was removed in #338 for now.

[luizgrp]

After #338 was merged, now a PR up to date with develop also failed with NPE:

java.lang.NullPointerException: goldenImage must not be null
	at app.cash.paparazzi.SnapshotVerifier$newFrameHandler$1.handle(SnapshotVerifier.kt:53)
	at app.cash.paparazzi.Paparazzi$takeSnapshots$1$2.invoke(Paparazzi.kt:302)
	at app.cash.paparazzi.Paparazzi$takeSnapshots$1$2.invoke(Paparazzi.kt:295)
	at app.cash.paparazzi.Paparazzi.withTime(Paparazzi.kt:336)
	at app.cash.paparazzi.Paparazzi.takeSnapshots(Paparazzi.kt:295)
	at app.cash.paparazzi.Paparazzi.snapshot(Paparazzi.kt:211)
	at app.cash.paparazzi.Paparazzi.snapshot(Paparazzi.kt:204)
	at app.cash.paparazzi.Paparazzi.snapshot$default(Paparazzi.kt:195)
	at com.google.android.horologist.audio.ui.VolumeScreenIndividualTest.volumeScreenAtMaximum(VolumeScreenIndividualTest.kt:63)

So good news is that it does not seem to be related to our custom WearSnapshotHandler.
Bad news is that we still need to figure out what's causing it.

[luizgrp]

Potentially fixed by #350; it needs monitoring and this issue can be reopened.