GithubViewModel 테스트코드 작성

app/build.gradle.kts

@@ -75,4 +75,12 @@ dependencies {
     implementation("androidx.lifecycle:lifecycle-viewmodel-compose:2.6.1")
 
     implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.7.3")
+
+    // test
+    testImplementation("junit:junit:4.13.2")
+    testImplementation("com.google.truth:truth:1.1.3")
+    testImplementation("androidx.arch.core:core-testing:2.2.0")
+    testImplementation("androidx.test:core-ktx:1.5.0")
+    testImplementation("io.mockk:mockk:1.13.7")
+    testImplementation("org.jetbrains.kotlinx:kotlinx-coroutines-test:1.7.3")
 }

app/src/test/java/camp/nextstep/edu/github/GithubViewModelTest.kt

@@ -0,0 +1,94 @@
+/**
+ * @author Daewon on 02,September,2023
+ *
+ */
+
+package camp.nextstep.edu.github
+
+import androidx.arch.core.executor.testing.InstantTaskExecutorRule
+import camp.nextstep.edu.github.domain.model.GithubRepository
+import camp.nextstep.edu.github.domain.repository.NetworkRepository
+import com.google.common.truth.Truth.assertThat
+import io.mockk.coEvery
+import io.mockk.coVerify
+import io.mockk.mockk
+import kotlinx.coroutines.test.runTest
+import org.junit.Rule
+import org.junit.Test
+
+
+class GithubViewModelTest {
+
+    @get:Rule
+    val mainDispatcherRule = MainDispatcherRule()
+
+    @Rule
+    @JvmField
+    val instantExecutorRule = InstantTaskExecutorRule()
+
+    private lateinit var viewModel: GithubViewModel
+    private val networkRepository: NetworkRepository = mockk(relaxed = true)
+
+    @Test
+    fun `GithubViewModel이 생성되면, 정상적으로 통신할 경우 GithubRepository를 가져온다`() = runTest {
+        // given
+        coEvery { networkRepository.getRepositories() } returns Result.success(
+            listOf(
+                GithubRepository(
+                    fullName = "KwonDae",
+                    description = "KwonDae's repository",
+                )
+            )
+        )
+
+        // when
+        viewModel = GithubViewModel(networkRepository)
+
+        // then
+        coVerify { networkRepository.getRepositories() }
+        assertThat(viewModel.uiState.value).isEqualTo(
+            UiState.Success(
+                listOf(
+                    GithubRepository(
+                        fullName = "KwonDae",
+                        description = "KwonDae's repository",
+                    )
+                )
+            )
+        )
+    }
+
+    @Test
+    fun `GithubViewModel이 생성되고, 정상적으로 통신했으나 빈값인 경우, 빈화면이 노출되어야 한다`() = runTest {
+        // given
+        coEvery { networkRepository.getRepositories() } returns Result.success(emptyList())
+
+        // when
+        viewModel = GithubViewModel(networkRepository)
+
+        // then
+        coVerify { networkRepository.getRepositories() }
+        assertThat(viewModel.uiState.value).isEqualTo(
+            UiState.Success(emptyList())
+        )
+    }
+
+    @Test
+    fun `GithubViewModel이 생성되고, 통신이 실패하면, 에러메시지를 가져온다`() = runTest {
+        // given
+        val errorMessage = "통신에 실패하였습니다."
+        coEvery { networkRepository.getRepositories() } returns Result.failure(
+            Throwable(errorMessage)
+        )
+
+        // when
+        viewModel = GithubViewModel(networkRepository)
+
+        // then
+        coVerify { networkRepository.getRepositories() }
+        assertThat(viewModel.uiState.value).isEqualTo(
+            UiState.Error(errorMessage)
+        )
+    }
+
+}

app/src/test/java/camp/nextstep/edu/github/MainDispatcherRule.kt

@@ -0,0 +1,28 @@
+/**
+ * @author Daewon on 02,September,2023
+ *
+ */
+
+package camp.nextstep.edu.github
+
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.test.TestDispatcher
+import kotlinx.coroutines.test.UnconfinedTestDispatcher
+import kotlinx.coroutines.test.resetMain
+import kotlinx.coroutines.test.setMain
+import org.junit.rules.TestWatcher
+import org.junit.runner.Description
+
+@OptIn(ExperimentalCoroutinesApi::class)
+class MainDispatcherRule(
+    private val testDispatcher: TestDispatcher = UnconfinedTestDispatcher()
+) : TestWatcher() {
+    override fun starting(description: Description) {
+        Dispatchers.setMain(testDispatcher)
+    }
+
+    override fun finished(description: Description) {
+        Dispatchers.resetMain()
+    }
+}