Adds Koin

This commit not only adds Koin, but also configures a basic
infrastructure for testing, allowing us to change behaviors as needed.

app/build.gradle

@@ -1,5 +1,6 @@
 apply plugin: 'com.android.application'
 apply plugin: 'org.jetbrains.kotlin.android'
+apply plugin: 'org.jetbrains.kotlin.kapt'
 
 apply from: "$rootDir/gradle/coverage.gradle"
 
@@ -61,12 +62,19 @@ android {
 dependencies {
     implementation "com.android.support:appcompat-v7:$versions.supportLibrary"
 
+    implementation "android.arch.lifecycle:extensions:$versions.archComponents"
+    kapt "android.arch.lifecycle:compiler:$versions.archComponents"
+
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$versions.kotlin"
 
     implementation 'com.google.firebase:firebase-core:15.0.2'
 
+    implementation "org.koin:koin-android:$versions.koin"
+    implementation "org.koin:koin-android-architecture:$versions.koin"
+
     testImplementation 'junit:junit:4.12'
     testImplementation 'org.robolectric:robolectric:3.8'
+    testImplementation 'com.google.truth:truth:0.40'
 
     androidTestImplementation 'com.android.support.test:runner:1.0.2'
     androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'

app/src/debug/AndroidManifest.xml

@@ -0,0 +1,10 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="net.rafaeltoledo.social">
+
+    <application>
+        <meta-data
+            android:name="firebase_analytics_collection_deactivated"
+            android:value="true" />
+    </application>
+
+</manifest>

app/src/main/AndroidManifest.xml

@@ -3,6 +3,7 @@
     package="net.rafaeltoledo.social">
 
     <application
+        android:name=".SocialApp"
         android:allowBackup="false"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"

app/src/main/kotlin/net/rafaeltoledo/social/MainActivity.kt

@@ -1,5 +1,19 @@
 package net.rafaeltoledo.social
 
+import android.os.Bundle
 import android.support.v7.app.AppCompatActivity
+import android.widget.TextView
+import org.koin.android.architecture.ext.viewModel
 
-class MainActivity : AppCompatActivity()
+class MainActivity : AppCompatActivity() {
+
+    private val mainViewModel: MainViewModel by viewModel()
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(TextView(this).apply {
+            id = R.id.content
+            text = mainViewModel.getString()
+        })
+    }
+}

app/src/main/kotlin/net/rafaeltoledo/social/MainViewModel.kt

@@ -0,0 +1,8 @@
+package net.rafaeltoledo.social
+
+import android.arch.lifecycle.ViewModel
+
+class MainViewModel(private val string: String) : ViewModel() {
+
+    fun getString() = string
+}

app/src/main/kotlin/net/rafaeltoledo/social/SocialApp.kt

@@ -0,0 +1,17 @@
+package net.rafaeltoledo.social
+
+import android.app.Application
+import net.rafaeltoledo.social.di.firstModule
+import net.rafaeltoledo.social.di.viewModelModule
+import org.koin.android.ext.android.startKoin
+
+open class SocialApp : Application() {
+
+    override fun onCreate() {
+        super.onCreate()
+        startKoin(listOf(
+                viewModelModule,
+                firstModule
+        ))
+    }
+}

app/src/main/kotlin/net/rafaeltoledo/social/di/FirstModule.kt

@@ -0,0 +1,7 @@
+package net.rafaeltoledo.social.di
+
+import org.koin.dsl.module.applicationContext
+
+val firstModule = applicationContext {
+    bean { "Social App" }
+}

app/src/main/kotlin/net/rafaeltoledo/social/di/ViewModelModule.kt

@@ -0,0 +1,9 @@
+package net.rafaeltoledo.social.di
+
+import net.rafaeltoledo.social.MainViewModel
+import org.koin.android.architecture.ext.viewModel
+import org.koin.dsl.module.applicationContext
+
+val viewModelModule = applicationContext {
+    viewModel { MainViewModel(get()) }
+}

app/src/main/res/values/ids.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <item name="content" type="id" />
+</resources>

app/src/main/res/values/styles.xml

@@ -1,8 +1,6 @@
 <resources>
 
-    <!-- Base application theme. -->
-    <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
-        <!-- Customize your theme here. -->
+    <style name="AppTheme" parent="Theme.AppCompat.Light">
         <item name="colorPrimary">@color/colorPrimary</item>
         <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
         <item name="colorAccent">@color/colorSecondary</item>

app/src/test/kotlin/net/rafaeltoledo/social/MainActivityTest.kt

@@ -1,16 +1,28 @@
 package net.rafaeltoledo.social
 
-import org.junit.Assert.assertNotNull
+import android.widget.TextView
+import com.google.common.truth.Truth.assertThat
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.robolectric.Robolectric
 import org.robolectric.RobolectricTestRunner
+import org.robolectric.RuntimeEnvironment
 
 @RunWith(RobolectricTestRunner::class)
 class MainActivityTest {
 
     @Test
     fun checkIfActivityIsSuccessfullyCreated() {
-        assertNotNull(Robolectric.setupActivity(MainActivity::class.java))
+        // Arrange
+        val newValue = "Test Social App"
+        val app = RuntimeEnvironment.application as TestSocialApp
+        app.overrideStringValue(newValue)
+        val activity = Robolectric.setupActivity(MainActivity::class.java)
+
+        // Act - nothing to do
+
+        // Assert
+        val text = activity.findViewById<TextView>(R.id.content)
+        assertThat(text.text).isEqualTo(newValue)
     }
 }

app/src/test/kotlin/net/rafaeltoledo/social/TestSetup.kt

@@ -0,0 +1,18 @@
+package net.rafaeltoledo.social
+
+import org.koin.dsl.module.applicationContext
+import org.koin.standalone.StandAloneContext.loadKoinModules
+
+class TestSocialApp : SocialApp() {
+
+    fun overrideStringValue(newValue: String) {
+        // Override value
+        // This behavior should be explicit in a future version of Koin
+        // See: https://github.com/Ekito/koin/pull/123
+        loadKoinModules(listOf(
+                applicationContext {
+                    bean { newValue }
+                }
+        ))
+    }
+}

build.gradle

@@ -4,6 +4,8 @@ buildscript {
             'kotlin': '1.2.41',
             'supportLibrary': '27.1.1',
             'jacoco': '0.8.1',
+            'archComponents': '1.1.1',
+            'koin': '0.9.3',
     ]
 
     repositories {
@@ -14,7 +16,7 @@ buildscript {
     dependencies {
         classpath 'com.android.tools.build:gradle:3.1.2'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$versions.kotlin"
-        classpath 'com.google.gms:google-services:3.3.0'
+        classpath 'com.google.gms:google-services:3.3.1'
         classpath "org.jacoco:org.jacoco.core:$versions.jacoco"
         classpath 'org.kt3k.gradle.plugin:coveralls-gradle-plugin:2.8.2'
     }