build-test-publish

Build, Test & Publish

Overview

Guide users through testing Android apps, configuring Gradle builds, and publishing to the Google Play Store. Cover the testing pyramid, version catalogs, signing, and store listing requirements. Emphasis on testable architecture from the start — retrofitting tests is painful.

Disclaimer: This skill provides educational guidance for learning Android development. For production apps handling sensitive user data, payment processing, authentication, or security-critical features, consult a professional Android developer or security auditor.

Testing Pyramid

Start with this ratio as a guideline — adjust based on your app:

        /  UI Tests  \        ~10%  Compose UI tests, end-to-end
       / Integration  \       ~20%  ViewModel + Repository, Hilt test modules
      /   Unit Tests   \      ~70%  ViewModels, Repositories, Use Cases, Mappers

Test Type	What It Tests	Framework	Speed
Unit	Pure logic, ViewModels, mappers	JUnit 5 + MockK + Turbine	Milliseconds
Integration	ViewModel + real Repository, Room queries	JUnit 5 + Hilt testing + Room in-memory	Seconds
UI	Screen rendering, user interactions	Compose Testing (createComposeRule)	Seconds-minutes
End-to-End	Full user flows across screens	Compose Testing + Navigation	Minutes

Key Testing Libraries

Library	Purpose
JUnit 5	Test runner and assertions
MockK	Kotlin-first mocking (prefer over Mockito)
Turbine	Testing Kotlin Flow and StateFlow emissions
Compose Testing	ComposeTestRule, semantic matchers, actions
Hilt Testing	@HiltAndroidTest, test modules, @UninstallModules
Room Testing	In-memory database for DAO testing
Robolectric	Run Android tests on JVM (faster, less accurate)

Build Configuration Overview

Modern Android builds use:

• Version Catalogs (libs.versions.toml) — single source of truth for all dependency versions
• KSP (Kotlin Symbol Processing) — replaces kapt for annotation processing; faster, Kotlin-native
• Convention Plugins — shared build logic across modules (for multi-module projects)
• Build Types — debug (development) and release (production, minified, signed)
• Product Flavors — variants for different configurations (free/paid, staging/production)

Gradle Version Catalog Quick Reference

All dependencies declared in gradle/libs.versions.toml:

[versions]
agp = "8.7.0"  # Update these to current stable
kotlin = "2.1.0"
compose-bom = "2025.01.01"

[libraries]
androidx-compose-bom = { group = "androidx.compose", name = "compose-bom", version.ref = "compose-bom" }

[plugins]
android-application = { id = "com.android.application", version.ref = "agp" }
kotlin-android = { id = "org.jetbrains.kotlin.android", version.ref = "kotlin" }
compose-compiler = { id = "org.jetbrains.kotlin.plugin.compose", version.ref = "kotlin" }

Referenced in build.gradle.kts as libs.androidx.compose.bom, libs.plugins.android.application, etc.

Publishing Requirements

Play Store requires these for launch:

Requirement	Details
Format	Android App Bundle (AAB), not APK
Target SDK	Must target current rolling requirement (check Play Console for deadline)
Signing	Upload key (managed by Play App Signing recommended)
Store Listing	Title, descriptions, screenshots (phone + tablet if supporting), feature graphic
Privacy Policy	Required URL if app collects any user data
Content Rating	Complete IARC questionnaire
Data Safety	Declare all data collection, sharing, and security practices
Testing	At least internal testing track before production release

Gradle Troubleshooting Top 5

Issue	Cause	Fix
Could not resolve dependency	Missing repository or wrong version	Check google() and mavenCentral() in repositories; verify version exists
Build takes forever	No build cache, no parallel execution	Enable org.gradle.caching=true and org.gradle.parallel=true in gradle.properties
Duplicate class error	Transitive dependency conflict	Use ./gradlew dependencies to find conflict; exclude or force version
KSP/kapt errors after update	Processor version mismatch	Align KSP version with Kotlin version exactly
Execution failed for task :app:merge*	Resource or manifest conflict	Check for duplicate resources across modules/flavors

References

• references/gradle-guide.md — Build config, version catalogs, KSP migration, multi-module setup
• references/testing-strategy.md — Unit, integration, and UI testing with complete code examples
• references/publishing-checklist.md — Play Store step-by-step from signing to release