[둘리] 1단계 자동 DI 미션 제출합니다

README.md

@@ -1 +1,31 @@
 # android-di
+# 0.5단계
+## 기능 요구 사항
+### 생성자 주입 - 수동
+다음 문제점을 해결한다.
+
+- [x] DB 없이 테스트하기 어렵다.
+- [x] DB 객체를 교체하기 위해 또다른 객체를 만들어 바꿔줘야 한다. 즉, ViewModel에 직접적인 변경사항이 발생한다.
+
+# 1단계
+## 기능 요구 사항
+### 생성자 주입 - 자동
+다음 문제점을 해결한다.
+
+- [x] ViewModel에서 참조하는 Repository가 정상적으로 주입되지 않는다.
+- [x] Repository를 참조하는 다른 객체가 생기면 주입 코드를 매번 만들어줘야 한다.
+- [x] ViewModel에 수동으로 주입되고 있는 의존성들을 자동으로 주입되도록 바꿔본다.
+- [x] 특정 ViewModel에서만이 아닌, 범용적으로 활용될 수 있는 자동 주입 로직을 작성한다. (MainViewModel, CartViewModel 모두 하나의 로직만 참조한다)
+- [x] 100개의 ViewModel이 생긴다고 가정했을 때, 자동 주입 로직 100개가 생기는 것이 아니다. 하나의 자동 주입 로직을 재사용할 수 있어야 한다.
+- [x] 장바구니에 접근할 때마다 매번 CartRepository 인스턴스를 새로 만들고 있다.
+- [x] 여러 번 인스턴스화할 필요 없는 객체는 최초 한 번만 인스턴스화한다. (이 단계에서는 너무 깊게 생각하지 말고 싱글 오브젝트로 구현해도 된다.)
+
+## 선택 요구 사항
+- [ ] TDD로 DI 구현
+- [x] Robolectric으로 기능 테스트
+- [ ] ViewModel 테스트
+- [ ] 모든 도메인 로직, Repository 단위 테스트
+
+## 프로그래밍 요구 사항
+사전에 주어진 테스트 코드가 모두 성공해야 한다.
+Annotation은 이 단계에서 활용하지 않는다.

app/build.gradle.kts

@@ -23,7 +23,7 @@ android {
             isMinifyEnabled = false
             proguardFiles(
                 getDefaultProguardFile("proguard-android-optimize.txt"),
-                "proguard-rules.pro"
+                "proguard-rules.pro",
             )
         }
     }
@@ -68,4 +68,7 @@ dependencies {
     implementation("com.github.bumptech.glide:glide:4.15.1")
     // Robolectric
     testImplementation("org.robolectric:robolectric:4.9")
+
+    implementation("androidx.fragment:fragment-ktx:1.5.7")
+    implementation(kotlin("reflect"))
 }

app/src/main/AndroidManifest.xml

@@ -5,6 +5,7 @@
     <uses-permission android:name="android.permission.INTERNET" />
 
     <application
+        android:name=".ui.ShoppingApplication"
         android:allowBackup="true"
         android:dataExtractionRules="@xml/data_extraction_rules"
         android:fullBackupContent="@xml/backup_rules"

app/src/main/java/woowacourse/shopping/data/CartRepository.kt → app/src/main/java/woowacourse/shopping/data/CartRepositoryImpl.kt

@@ -3,18 +3,17 @@ package woowacourse.shopping.data
 import woowacourse.shopping.model.Product
 
 // TODO: Step2 - CartProductDao를 참조하도록 변경
-class CartRepository {
-
+class CartRepositoryImpl : CartRepository {
     private val cartProducts: MutableList<Product> = mutableListOf()
-    fun addCartProduct(product: Product) {
+    override fun addCartProduct(product: Product) {
         cartProducts.add(product)
     }
 
-    fun getAllCartProducts(): List<Product> {
+    override fun getAllCartProducts(): List<Product> {
         return cartProducts.toList()
     }
 
-    fun deleteCartProduct(id: Int) {
+    override fun deleteCartProduct(id: Int) {
         cartProducts.removeAt(id)
     }
 }

app/src/main/java/woowacourse/shopping/data/ProductRepository.kt → app/src/main/java/woowacourse/shopping/data/ProductRepositoryImpl.kt

@@ -2,27 +2,26 @@ package woowacourse.shopping.data
 
 import woowacourse.shopping.model.Product
 
-class ProductRepository {
-
+class ProductRepositoryImpl : ProductRepository {
     private val products: List<Product> = listOf(
         Product(
             name = "우테코 과자",
             price = 10_000,
-            imageUrl = "https://cdn-mart.baemin.com/sellergoods/api/main/df6d76fb-925b-40f8-9d1c-f0920c3c697a.jpg?h=700&w=700"
+            imageUrl = "https://cdn-mart.baemin.com/sellergoods/api/main/df6d76fb-925b-40f8-9d1c-f0920c3c697a.jpg?h=700&w=700",
         ),
         Product(
             name = "우테코 쥬스",
             price = 8_000,
-            imageUrl = "https://cdn-mart.baemin.com/sellergoods/main/52dca718-31c5-4f80-bafa-7e300d8c876a.jpg?h=700&w=700"
+            imageUrl = "https://cdn-mart.baemin.com/sellergoods/main/52dca718-31c5-4f80-bafa-7e300d8c876a.jpg?h=700&w=700",
         ),
         Product(
             name = "우테코 아이스크림",
             price = 20_000,
-            imageUrl = "https://cdn-mart.baemin.com/sellergoods/main/e703c53e-5d01-4b20-bd33-85b5e778e73f.jpg?h=700&w=700"
+            imageUrl = "https://cdn-mart.baemin.com/sellergoods/main/e703c53e-5d01-4b20-bd33-85b5e778e73f.jpg?h=700&w=700",
         ),
     )
 
-    fun getAllProducts(): List<Product> {
+    override fun getAllProducts(): List<Product> {
         return products
     }
 }

app/src/main/java/woowacourse/shopping/di/Container.kt

@@ -0,0 +1,17 @@
+package woowacourse.shopping.di
+
+import kotlin.reflect.KClass
+
+object Container {
+    private val instances = mutableMapOf<KClass<*>, Any>()
+    fun addInstance(type: KClass<*>, instance: Any) {
+        instances[type] = instance
+    }
+
+    fun getInstance(type: KClass<*>): Any =
+        instances[type] ?: throw NoSuchElementException("Unknown Instance")
+
+    fun clear() {
+        instances.clear()
+    }
+}

app/src/main/java/woowacourse/shopping/di/ViewModelInjector.kt

@@ -0,0 +1,25 @@
+package woowacourse.shopping.di
+
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.ViewModelProvider
+import androidx.lifecycle.viewmodel.initializer
+import androidx.lifecycle.viewmodel.viewModelFactory
+import kotlin.reflect.full.primaryConstructor
+import kotlin.reflect.jvm.jvmErasure
+
+object ViewModelInjector {
+    inline fun <reified T : ViewModel> getInjectedViewModelFactory(): ViewModelProvider.Factory {
+        val constructor = T::class.primaryConstructor
+        requireNotNull(constructor) { "Unknown ViewModel Class ${T::class}" }
+
+        val instances = constructor.parameters.map {
+            Container.getInstance(it.type.jvmErasure)
+        }
+
+        return viewModelFactory {
+            initializer {
+                constructor.call(*instances.toTypedArray())
+            }
+        }
+    }
+}

app/src/main/java/woowacourse/shopping/ui/MainActivity.kt

@@ -4,19 +4,18 @@ import android.content.Intent
 import android.os.Bundle
 import android.view.Menu
 import android.widget.Toast
+import androidx.activity.viewModels
 import androidx.appcompat.app.AppCompatActivity
-import androidx.lifecycle.ViewModelProvider
 import woowacourse.shopping.R
 import woowacourse.shopping.databinding.ActivityMainBinding
+import woowacourse.shopping.di.ViewModelInjector
 import woowacourse.shopping.ui.cart.CartActivity
 
 class MainActivity : AppCompatActivity() {
 
     private val binding by lazy { ActivityMainBinding.inflate(layoutInflater) }
 
-    private val viewModel by lazy {
-        ViewModelProvider(this)[MainViewModel::class.java]
-    }
+    private val viewModel by viewModels<MainViewModel> { ViewModelInjector.getInjectedViewModelFactory<MainViewModel>() }
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -27,7 +26,6 @@ class MainActivity : AppCompatActivity() {
         setupView()
     }
 
-
     override fun onCreateOptionsMenu(menu: Menu?): Boolean {
         menuInflater.inflate(R.menu.cart_menu, menu)
         menu?.findItem(R.id.cart)?.actionView?.let { view ->
@@ -58,7 +56,7 @@ class MainActivity : AppCompatActivity() {
         viewModel.products.observe(this) {
             val adapter = ProductAdapter(
                 items = it,
-                onClickProduct = viewModel::addCartProduct
+                onClickProduct = viewModel::addCartProduct,
             )
             binding.rvProducts.adapter = adapter
         }

app/src/main/java/woowacourse/shopping/ui/MainViewModel.kt

@@ -18,7 +18,6 @@ class MainViewModel(
     private val _onProductAdded: MutableLiveData<Boolean> = MutableLiveData(false)
     val onProductAdded: LiveData<Boolean> get() = _onProductAdded
 
-
     fun addCartProduct(product: Product) {
         cartRepository.addCartProduct(product)
         _onProductAdded.value = true

app/src/main/java/woowacourse/shopping/ui/ShoppingApplication.kt

@@ -0,0 +1,20 @@
+package woowacourse.shopping.ui
+
+import android.app.Application
+import woowacourse.shopping.data.CartRepository
+import woowacourse.shopping.data.CartRepositoryImpl
+import woowacourse.shopping.data.ProductRepository
+import woowacourse.shopping.data.ProductRepositoryImpl
+import woowacourse.shopping.di.Container
+
+class ShoppingApplication : Application() {
+    override fun onCreate() {
+        super.onCreate()
+        inject()
+    }
+
+    private fun inject() {
+        Container.addInstance(CartRepository::class, CartRepositoryImpl())
+        Container.addInstance(ProductRepository::class, ProductRepositoryImpl())
+    }
+}

app/src/main/java/woowacourse/shopping/ui/cart/CartActivity.kt

@@ -2,18 +2,17 @@ package woowacourse.shopping.ui.cart
 
 import android.os.Bundle
 import android.widget.Toast
+import androidx.activity.viewModels
 import androidx.appcompat.app.AppCompatActivity
-import androidx.lifecycle.ViewModelProvider
 import woowacourse.shopping.R
 import woowacourse.shopping.databinding.ActivityCartBinding
+import woowacourse.shopping.di.ViewModelInjector
 
 class CartActivity : AppCompatActivity() {
 
     private val binding by lazy { ActivityCartBinding.inflate(layoutInflater) }
 
-    private val viewModel by lazy {
-        ViewModelProvider(this)[CartViewModel::class.java]
-    }
+    private val viewModel by viewModels<CartViewModel> { ViewModelInjector.getInjectedViewModelFactory<CartViewModel>() }
 
     private lateinit var dateFormatter: DateFormatter
 
@@ -60,7 +59,7 @@ class CartActivity : AppCompatActivity() {
             val adapter = CartProductAdapter(
                 items = it,
                 dateFormatter = dateFormatter,
-                onClickDelete = viewModel::deleteCartProduct
+                onClickDelete = viewModel::deleteCartProduct,
             )
             binding.rvCartProducts.adapter = adapter
         }

app/src/test/java/woowacourse/shopping/activity/CartActivityTest.kt

@@ -0,0 +1,44 @@
+package woowacourse.shopping.activity
+
+import androidx.arch.core.executor.testing.InstantTaskExecutorRule
+import androidx.lifecycle.ViewModelProvider
+import com.google.common.truth.Truth.assertThat
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.Robolectric
+import org.robolectric.RobolectricTestRunner
+import woowacourse.shopping.ui.cart.CartActivity
+import woowacourse.shopping.ui.cart.CartViewModel
+
+@RunWith(RobolectricTestRunner::class)
+class CartActivityTest {
+
+    @get:Rule
+    var instantTaskExecutorRule = InstantTaskExecutorRule() // AAC 컴포넌트들을 한 스레드에서 실행되도록 함
+
+    @Test
+    fun `Activity 실행 테스트`() {
+        // given
+        val activity = Robolectric
+            .buildActivity(CartActivity::class.java)
+            .create()
+            .get()
+
+        // then
+        assertThat(activity).isNotNull()
+    }
+
+    @Test
+    fun `ViewModel 주입 테스트`() {
+        // given
+        val activity = Robolectric
+            .buildActivity(CartActivity::class.java)
+            .create()
+            .get()
+        val viewModel = ViewModelProvider(activity)[CartViewModel::class.java]
+
+        // then
+        assertThat(viewModel).isNotNull()
+    }
+}

app/src/test/java/woowacourse/shopping/MainActivityTest.kt → app/src/test/java/woowacourse/shopping/activity/MainActivityTest.kt

@@ -1,4 +1,4 @@
-package woowacourse.shopping
+package woowacourse.shopping.activity
 
 import androidx.arch.core.executor.testing.InstantTaskExecutorRule
 import androidx.lifecycle.ViewModelProvider
@@ -11,12 +11,11 @@ import org.robolectric.RobolectricTestRunner
 import woowacourse.shopping.ui.MainActivity
 import woowacourse.shopping.ui.MainViewModel
 
-
 @RunWith(RobolectricTestRunner::class)
 class MainActivityTest {
 
     @get:Rule
-    var instantTaskExecutorRule = InstantTaskExecutorRule()
+    var instantTaskExecutorRule = InstantTaskExecutorRule() // AAC 컴포넌트들을 한 스레드에서 실행되도록 함
 
     @Test
     fun `Activity 실행 테스트`() {

app/src/test/java/woowacourse/shopping/getOrAwaitValue.kt → app/src/test/java/woowacourse/shopping/activity/getOrAwaitValue.kt

@@ -1,4 +1,4 @@
-package woowacourse.shopping
+package woowacourse.shopping.activity
 
 import androidx.lifecycle.LiveData
 import androidx.lifecycle.Observer

app/src/test/java/woowacourse/shopping/di/ViewModelInjectorTest.kt

@@ -0,0 +1,59 @@
+package woowacourse.shopping.di
+
+import androidx.activity.viewModels
+import androidx.appcompat.app.AppCompatActivity
+import androidx.lifecycle.ViewModel
+import junit.framework.TestCase.assertEquals
+import junit.framework.TestCase.assertNotNull
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.Robolectric
+import org.robolectric.RobolectricTestRunner
+
+interface FakeRepository
+class FakeRepositoryImpl : FakeRepository
+class FakeViewModel(
+    val fakeRepository: FakeRepository,
+) : ViewModel()
+
+class FakeActivity : AppCompatActivity() {
+    val viewModel by viewModels<FakeViewModel> { ViewModelInjector.getInjectedViewModelFactory<FakeViewModel>() }
+}
+
+@RunWith(RobolectricTestRunner::class)
+class ViewModelInjectorTest {
+
+    @Before
+    fun setup() {
+        Container.clear()
+    }
+
+    @Test
+    fun `Container에서 타입에 맞는 instance를 찾아 ViewModel 의존성을 주입한다`() {
+        // given
+        val repository = FakeRepositoryImpl()
+        Container.addInstance(FakeRepository::class, repository)
+        val activity = Robolectric
+            .buildActivity(FakeActivity::class.java)
+            .create()
+            .get()
+
+        // when
+        val viewModel = activity.viewModel
+
+        // then
+        assertNotNull(viewModel)
+        assertEquals(viewModel.fakeRepository, repository)
+    }
+
+    @Test(expected = NoSuchElementException::class)
+    fun `Container에 타입에 맞는 instance가 없으면 ViewModel 의존성 주입에 실패하여 에러가 발생한다`() {
+        val activity = Robolectric
+            .buildActivity(FakeActivity::class.java)
+            .create()
+            .get()
+
+        activity.viewModel
+    }
+}

domain/src/main/java/woowacourse/shopping/data/CartRepository.kt

@@ -0,0 +1,11 @@
+package woowacourse.shopping.data
+
+import woowacourse.shopping.model.Product
+
+interface CartRepository {
+    fun addCartProduct(product: Product)
+
+    fun getAllCartProducts(): List<Product>
+
+    fun deleteCartProduct(id: Int)
+}