Optimization suggestion for reducing test initialization time with ParameterizedRobolectricTestRunner

[takahirom]

Thanks as always! I've been using the ComposablePreviewScanner library and noticed that each test takes approximately 1-5 seconds, which significantly increases the total test duration. It seems that ParameterizedRobolectricTestRunner.Parameters is invoked for each test. I found that using a lazy initialization for the previews can optimize performance. Here's a snippet that could potentially be included in the README:

companion object {
  private val previewsCache: List<ComposablePreview<AndroidPreviewInfo>> by lazy {
    val (value, time) = measureTimedValue {
      AndroidComposablePreviewScanner()
        .scanPackageTrees("your.package")
        .getPreviews()
    }
    println("Compose Preview Scanning took $time")
    value
  }

  @JvmStatic
  @ParameterizedRobolectricTestRunner.Parameters
  fun values(): List<ComposablePreview<AndroidPreviewInfo>> {
    return previewsCache
  }
}

Would it be possible to consider this approach for inclusion in the documentation to help others improve the performance of their tests?

[sergio-sastre]

Definitely! Thanks for taking the time to investigate the cause of the issue 🙏

[sergio-sastre]

Added to the docu. Thanks!