feat: add screenshot testing using gcp

[Manabu-GT]

Summary by CodeRabbit

• Tests

  • Implemented screenshot testing to validate visual components across multiple states.
  • Added CI steps to run screenshot verification and collect/upload screenshot-diff reports for review.

• Chores

  • Added build configuration and dependencies to enable screenshot testing support.

[coderabbitai]

Caution

Review failed

The pull request is closed.

📝 Walkthrough

Walkthrough

Adds Compose screenshot testing: Gradle plugin/version/dependencies and an experimental flag; introduces screenshot preview tests and a reusable EffectCard; updates CI to run a screenshot validation step (continue-on-error) and always upload screenshot diff artifacts with 14-day retention.

Changes

Cohort / File(s)	Summary
CI/CD Workflow .github/workflows/android-ci.yml	Adds "Screenshot test (verify)" step (runs ./gradlew :aether:validateDebugScreenshotTest with continue-on-error) and an "Upload screenshot diffs" artifact upload step that always runs, uploading aether/build/reports/screenshotTest/ with 14-day retention.
Root build config build.gradle.kts, gradle/libs.versions.toml, gradle.properties	Adds libs.plugins.screenshot plugin alias, adds screenshot version and screenshot-validation-api/androidx-ui-tooling library entries, and sets android.experimental.enableScreenshotTest=true property.
Module build config aether/build.gradle.kts	Applies screenshot plugin alias (via plugins block), enables android.experimental.enableScreenshotTest in android.experimentalProperties, and adds screenshotTestImplementation deps for screenshot validation API and Compose UI tooling.
Screenshot Test Suite aether/src/screenshotTest/kotlin/.../EffectCard.kt, .../CloudsScreenshots.kt, .../RainScreenshots.kt, .../SnowScreenshots.kt, .../LightningFlashScreenshots.kt	Adds EffectCard composable used by new preview screenshot tests; introduces multiple internal @PreviewTest preview composables covering Clouds, Rain, Snow, and LightningFlash variants for screenshot validation.

Sequence Diagram(s)

sequenceDiagram
    participant Dev as "Developer / PR"
    participant CI as "GitHub Actions CI"
    participant Gradle as "Gradle (validateDebugScreenshotTest)"
    participant Artifact as "Actions Artifact Storage"

    rect rgba(220,240,255,0.5)
    Dev->>CI: Push PR / trigger workflow
    end

    CI->>Gradle: Run checks
    CI->>Gradle: ./gradlew :aether:validateDebugScreenshotTest
    Gradle-->>CI: Screenshot validation results (may continue on error)
    CI->>Artifact: Upload aether/build/reports/screenshotTest/ (always)
    Artifact-->>CI: Artifact stored (14d retention)
    CI-->>Dev: Workflow status + artifacts link

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Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

🚥 Pre-merge checks | ✅ 3 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: adding screenshot testing infrastructure using GCP. It is specific, clear, and directly reflects the primary objective of the changeset.
Merge Conflict Detection	✅ Passed	✅ No merge conflicts detected when merging into main

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch feature/14-screenshot-tests

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[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@gradle/libs.versions.toml`:
- Line 36: Remove the unused version catalog entries for coreKtx and the library
alias androidx-core-ktx: delete the coreKtx = "1.17.0" version declaration and
the androidx-core-ktx library declaration (the alias referencing coreKtx) from
the versions TOML, then run a Gradle sync/build to ensure no remaining
references; if any references exist, replace them with the appropriate
alternative dependency or remove the usage.

🧹 Nitpick comments (2)

gradle.properties (1)

8-9: Redundant with experimentalProperties in aether/build.gradle.kts.

This property is also set via experimentalProperties["android.experimental.enableScreenshotTest"] = true in aether/build.gradle.kts (line 32). Setting it in gradle.properties enables it globally for all modules, which may be broader than intended. Consider keeping it only in the module-level build file where screenshot tests actually live.

aether/src/screenshotTest/kotlin/com/ms/square/aether/screenshot/EffectCard.kt (1)

10-13: Consider specifying explicit preview dimensions for deterministic screenshots.

EffectCard uses fillMaxSize(), and none of the @Preview annotations in the test files specify widthDp/heightDp. The default preview size should be consistent across runs, but explicitly setting dimensions (either here or on the @Preview annotations) would make the expected output size obvious and guard against tooling defaults changing.

Also applies to: 18-29