[Tests] Unit and integration tests for Stats Collection

[LeGeRyChEeSe]

Description

Set up the test strategy for the Stats Collection module.

Test files to create

• app/src/test/java/com/vrhub/data/StatsCollectorTest.kt
• app/src/test/java/com/vrhub/data/ConsentPreferencesTest.kt
• app/src/androidTest/java/com/vrhub/.../StatsCollectionIntegrationTest.kt

Unit test scenarios (StatsCollector)

• collectStats does nothing when consent is false (no network call)
• collectStats sends correct payload when consent is true
• collectStats includes correct package_name and is_favorite
• collectStats includes correct tier and timestamp
• updateConsent calls API with correct value
• getUserTier returns tier or null on error

Unit test scenarios (ConsentPreferences)

• consentEnabled emits false by default
• setConsentEnabled(true) persists and emits true
• setConsentEnabled(false) persists and emits false

Integration test scenarios

• Full flow: consent granted → stats sent → worker enqueued
• Consent revoked → worker cancelled
• Favorite change → triggers maybeCollectStats()

Required mocks

• FakeStatsApiService implementing StatsApiService
• FakeConsentPreferences or in-memory DataStore usage

Reference

• docs/CLIENT_IMPLEMENTATION.md §10