Android Screenshot Testing on Autopilot
summary
Converts Jetpack Compose previews into runnable screenshot tests by using a KSP code generator that finds @Preview functions, emits JUnit 5 + Paparazzi test classes, and a custom Gradle plugin that mounts the generated folder as a test source set, injects compileOnly test deps, runs the record/verify tasks and then removes the deps. Implementation handles preview parameters (named via a PreviewParameterProvider), throws on duplicate names, and runs in real projects — producing over 1,000 PNGs with zero manual test code and ~6–8 minute full generation.
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chapters (14)
- 0:00Automated screenshot testing
- 1:09Manual testing problems
- 4:03Manual to automated workflow
- 7:36Test source set challenge
- 9:22Live demo setup
- 15:14Dependencies and annotations
- 16:59Gradle plugin compilation
- 20:33Auto-generating screenshot tests
- 23:00Preview parameters handling
- 27:00Results and impact
- 28:45Advanced config improvements
- 31:41CI integration
- 37:20Paparazzi future and Google's approach
- 40:44Incremental builds
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