Example migration of Android application from Java to Kotlin - DO NOT MERGE

app/build.gradle

@@ -44,13 +44,14 @@ dependencies {
     compile 'io.reactivex.rxjava2:rxandroid:2.0.0'
     compile 'com.jakewharton.timber:timber:4.3.0'
     compile 'com.jakewharton:butterknife:8.4.0'
-    annotationProcessor 'com.jakewharton:butterknife-compiler:8.4.0'
+    compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
+    kapt 'com.jakewharton:butterknife-compiler:8.4.0'
 
-    testCompile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
     testCompile "org.jetbrains.kotlin:kotlin-test-junit:$kotlin_version"
     testCompile 'junit:junit:4.12'
     testCompile 'org.mockito:mockito-core:2.10.0'
     testCompile 'org.assertj:assertj-core:3.8.0'
+    testCompile "com.nhaarman:mockito-kotlin-kt1.1:1.5.0"
 
     androidTestCompile 'com.android.support.test:runner:1.0.1'
     androidTestCompile 'com.android.support.test:rules:1.0.1'

app/src/main/kotlin/com/example/unittesting/BasePresenter.kt

@@ -0,0 +1,23 @@
+package com.example.unittesting
+
+import io.reactivex.disposables.CompositeDisposable
+import io.reactivex.disposables.Disposable
+
+open class BasePresenter<T> : Presenter<T> {
+
+    var view: T? = null
+    private val compositeDisposable = CompositeDisposable()
+
+    override fun createView(view: T) {
+        this.view = view
+    }
+
+    fun bindToLifecycle(disposable: Disposable) {
+        compositeDisposable.add(disposable)
+    }
+
+    override fun destroyView() {
+        compositeDisposable.clear()
+        view = null
+    }
+}

app/src/main/kotlin/com/example/unittesting/Presenter.kt

@@ -0,0 +1,8 @@
+package com.example.unittesting
+
+internal interface Presenter<in T> {
+
+    fun createView(view: T)
+
+    fun destroyView()
+}

app/src/main/kotlin/com/example/unittesting/ResourceProvider.kt

@@ -0,0 +1,11 @@
+package com.example.unittesting
+
+import android.content.res.Resources
+import android.support.annotation.StringRes
+
+class ResourceProvider(private var resources: Resources) {
+
+    fun getString(@StringRes stringResId: Int): String {
+        return resources.getString(stringResId)
+    }
+}

app/src/main/kotlin/com/example/unittesting/SchedulersFactory.kt

@@ -0,0 +1,20 @@
+package com.example.unittesting
+
+import io.reactivex.Observable
+import io.reactivex.ObservableSource
+import io.reactivex.ObservableTransformer
+import io.reactivex.android.schedulers.AndroidSchedulers
+
+class SchedulersFactory {
+
+    fun <T> createMainThreadSchedulerTransformer(): ObservableTransformer<T, T> {
+        return SchedulersTransformer()
+    }
+}
+
+internal class SchedulersTransformer<T> : ObservableTransformer<T, T> {
+
+    override fun apply(upstream: Observable<T>): ObservableSource<T> {
+        return upstream.observeOn(AndroidSchedulers.mainThread())
+    }
+}

app/src/main/kotlin/com/example/unittesting/login/model/LoginCredentials.kt

@@ -0,0 +1,3 @@
+package com.example.unittesting.login.model
+
+data class LoginCredentials(val login: String, val password: String)

app/src/main/kotlin/com/example/unittesting/login/model/LoginRepository.kt

@@ -0,0 +1,21 @@
+package com.example.unittesting.login.model
+
+import io.reactivex.Observable
+import io.reactivex.Observable.fromCallable
+import timber.log.Timber
+import java.util.concurrent.TimeUnit
+
+class LoginRepository {
+
+    fun login(login: String, password: String): Observable<Boolean> {
+        Timber.v("login %s with password %s", login, password)
+
+        return fromCallable { CORRECT_LOGIN == login && CORRECT_PASSWORD == password }
+                .delay(2000, TimeUnit.MILLISECONDS)
+    }
+
+    companion object {
+        internal val CORRECT_LOGIN = "dbacinski"
+        internal val CORRECT_PASSWORD = "correct"
+    }
+}

app/src/main/kotlin/com/example/unittesting/login/model/LoginUseCase.kt

@@ -0,0 +1,10 @@
+package com.example.unittesting.login.model
+
+import io.reactivex.Observable
+
+class LoginUseCase(private val loginRepository: LoginRepository) {
+
+    fun loginWithCredentialsWithStatus(credentials: LoginCredentials): Observable<Boolean> {
+        return loginRepository.login(credentials.login, credentials.password)
+    }
+}

app/src/main/kotlin/com/example/unittesting/login/model/LoginValidator.kt

@@ -0,0 +1,17 @@
+package com.example.unittesting.login.model
+
+class LoginValidator {
+
+    companion object {
+        val EMPTY = ""
+        val MIN_PASSWORD_LENGTH = 6
+    }
+
+    fun validateLogin(login: String): Boolean {
+        return login != EMPTY
+    }
+
+    fun validatePassword(password: String): Boolean {
+        return password.length >= MIN_PASSWORD_LENGTH
+    }
+}