feat(creator): FanTalk 탭 상태 관리를 추가한다

2026-06-22 16:38:08 +09:00
parent b7eba4c99a
commit 50449f43ac
5 changed files with 717 additions and 0 deletions
--- a/app/src/test/java/kr/co/vividnext/sodalive/v2/creator/channel/fantalk/CreatorChannelFanTalkActionTest.kt
+++ b/app/src/test/java/kr/co/vividnext/sodalive/v2/creator/channel/fantalk/CreatorChannelFanTalkActionTest.kt
@@ -0,0 +1,168 @@
+package kr.co.vividnext.sodalive.v2.creator.channel.fantalk
+
+import android.app.Application
+import android.content.Context
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.Observer
+import androidx.test.core.app.ApplicationProvider
+import io.reactivex.rxjava3.android.plugins.RxAndroidPlugins
+import io.reactivex.rxjava3.core.Scheduler
+import io.reactivex.rxjava3.core.Single
+import io.reactivex.rxjava3.plugins.RxJavaPlugins
+import io.reactivex.rxjava3.schedulers.Schedulers
+import kr.co.vividnext.sodalive.R
+import kr.co.vividnext.sodalive.common.SodaLiveApplicationHolder
+import kr.co.vividnext.sodalive.common.ApiResponse
+import kr.co.vividnext.sodalive.common.AndroidUtcRelativeTimeTextFormatter
+import kr.co.vividnext.sodalive.common.SharedPreferenceManager
+import kr.co.vividnext.sodalive.v2.creator.channel.data.CreatorChannelRepository
+import kr.co.vividnext.sodalive.v2.creator.channel.fantalk.data.CreatorChannelFanTalkResponse
+import kr.co.vividnext.sodalive.v2.creator.channel.fantalk.data.CreatorChannelFanTalkTabResponse
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.kotlin.times
+import org.mockito.kotlin.verify
+import org.mockito.kotlin.whenever
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [28], application = Application::class)
+class CreatorChannelFanTalkActionTest {
+
+    private val context: Context = ApplicationProvider.getApplicationContext()
+    private lateinit var repository: CreatorChannelRepository
+    private lateinit var viewModel: CreatorChannelFanTalkViewModel
+
+    @Before
+    fun setUp() {
+        setImmediateRxSchedulers()
+        SharedPreferenceManager.resetForTest()
+        SodaLiveApplicationHolder.init(context as Application)
+        SharedPreferenceManager.init(context)
+        SharedPreferenceManager.token = "test-token"
+        SharedPreferenceManager.userId = 10L
+        repository = org.mockito.kotlin.mock()
+        viewModel = CreatorChannelFanTalkViewModel(repository, AndroidUtcRelativeTimeTextFormatter(context))
+    }
+
+    @After
+    fun tearDown() {
+        RxJavaPlugins.reset()
+        RxAndroidPlugins.reset()
+        SharedPreferenceManager.resetForTest()
+    }
+
+    @Test
+    fun `신고 성공 시 action toast message가 설정된다`() {
+        stubFirstPage(ids = listOf(1L))
+        whenever(repository.reportFanTalk(1L, "spam", "Bearer test-token"))
+            .thenReturn(Single.just(ApiResponse(true, Any(), "reported")))
+        viewModel.loadFanTalks(100L, isOwner = false)
+
+        viewModel.reportFanTalk(1L, "spam")
+
+        val state = viewModel.fanTalkStateLiveData.requireValue() as CreatorChannelFanTalkUiState.Content
+        assertEquals("reported", state.actionToastMessage)
+    }
+
+    @Test
+    fun `신고 성공 응답 message가 null이면 접수 완료 fallback toast message가 설정된다`() {
+        stubFirstPage(ids = listOf(1L))
+        whenever(repository.reportFanTalk(1L, "spam", "Bearer test-token"))
+            .thenReturn(Single.just(ApiResponse(true, Any(), null)))
+        viewModel.loadFanTalks(100L, isOwner = false)
+
+        viewModel.reportFanTalk(1L, "spam")
+
+        val state = viewModel.fanTalkStateLiveData.requireValue() as CreatorChannelFanTalkUiState.Content
+        assertEquals(context.getString(R.string.character_comment_report_submitted), state.actionToastMessage)
+    }
+
+    @Test
+    fun `신고 실패 시 기존 content 상태를 유지하고 toast message가 설정된다`() {
+        stubFirstPage(ids = listOf(1L))
+        whenever(repository.reportFanTalk(1L, "spam", "Bearer test-token"))
+            .thenReturn(Single.just(ApiResponse(false, null, "report failed")))
+        viewModel.loadFanTalks(100L, isOwner = false)
+
+        viewModel.reportFanTalk(1L, "spam")
+
+        val state = viewModel.fanTalkStateLiveData.requireValue() as CreatorChannelFanTalkUiState.Content
+        assertEquals(listOf(1L), state.fanTalks.map { it.fanTalkId })
+        assertEquals("report failed", state.actionToastMessage)
+    }
+
+    @Test
+    fun `삭제 성공 시 첫 페이지 refresh가 호출된다`() {
+        whenever(repository.getFanTalks(100L, 0, CreatorChannelFanTalkViewModel.DEFAULT_PAGE_SIZE, "Bearer test-token"))
+            .thenReturn(
+                Single.just(ApiResponse(true, fanTalkResponse(ids = listOf(1L)), null)),
+                Single.just(ApiResponse(true, fanTalkResponse(ids = listOf(2L)), null))
+            )
+        whenever(repository.deleteFanTalk(1L, "Bearer test-token"))
+            .thenReturn(Single.just(ApiResponse(true, Any(), "deleted")))
+        viewModel.loadFanTalks(100L, isOwner = false)
+
+        viewModel.deleteFanTalk(1L)
+
+        val state = viewModel.fanTalkStateLiveData.requireValue() as CreatorChannelFanTalkUiState.Content
+        assertEquals(listOf(2L), state.fanTalks.map { it.fanTalkId })
+        verify(repository, times(2)).getFanTalks(100L, 0, CreatorChannelFanTalkViewModel.DEFAULT_PAGE_SIZE, "Bearer test-token")
+    }
+
+    @Test
+    fun `삭제 실패 시 기존 content 상태를 유지하고 toast message가 설정된다`() {
+        stubFirstPage(ids = listOf(1L))
+        whenever(repository.deleteFanTalk(1L, "Bearer test-token"))
+            .thenReturn(Single.just(ApiResponse(false, null, "delete failed")))
+        viewModel.loadFanTalks(100L, isOwner = false)
+
+        viewModel.deleteFanTalk(1L)
+
+        val state = viewModel.fanTalkStateLiveData.requireValue() as CreatorChannelFanTalkUiState.Content
+        assertEquals(listOf(1L), state.fanTalks.map { it.fanTalkId })
+        assertEquals("delete failed", state.actionToastMessage)
+    }
+
+    private fun stubFirstPage(ids: List<Long>) {
+        whenever(repository.getFanTalks(100L, 0, CreatorChannelFanTalkViewModel.DEFAULT_PAGE_SIZE, "Bearer test-token"))
+            .thenReturn(Single.just(ApiResponse(true, fanTalkResponse(ids = ids), null)))
+    }
+
+    private fun setImmediateRxSchedulers() {
+        val trampoline = { _: Scheduler -> Schedulers.trampoline() }
+        RxJavaPlugins.setIoSchedulerHandler(trampoline)
+        RxAndroidPlugins.setInitMainThreadSchedulerHandler { Schedulers.trampoline() }
+        RxAndroidPlugins.setMainThreadSchedulerHandler { Schedulers.trampoline() }
+    }
+
+    private fun fanTalkResponse(ids: List<Long>) = CreatorChannelFanTalkTabResponse(
+        fanTalkCount = ids.size,
+        fanTalks = ids.map { fanTalk(it) },
+        page = 0,
+        size = CreatorChannelFanTalkViewModel.DEFAULT_PAGE_SIZE,
+        hasNext = false
+    )
+
+    private fun fanTalk(id: Long) = CreatorChannelFanTalkResponse(
+        fanTalkId = id,
+        writerId = 10L,
+        writerNickname = "writer",
+        writerProfileImageUrl = "profile.png",
+        content = "fan talk $id",
+        createdAtUtc = "2026-06-21T00:00:00Z",
+        creatorReplies = emptyList()
+    )
+
+    private fun <T> LiveData<T>.requireValue(): T? {
+        var value: T? = null
+        val observer = Observer<T> { value = it }
+        observeForever(observer)
+        removeObserver(observer)
+        return value
+    }
+}
--- a/app/src/test/java/kr/co/vividnext/sodalive/v2/creator/channel/fantalk/CreatorChannelFanTalkPaginationTest.kt
+++ b/app/src/test/java/kr/co/vividnext/sodalive/v2/creator/channel/fantalk/CreatorChannelFanTalkPaginationTest.kt
@@ -0,0 +1,163 @@
+package kr.co.vividnext.sodalive.v2.creator.channel.fantalk
+
+import android.app.Application
+import android.content.Context
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.Observer
+import androidx.test.core.app.ApplicationProvider
+import io.reactivex.rxjava3.android.plugins.RxAndroidPlugins
+import io.reactivex.rxjava3.core.Scheduler
+import io.reactivex.rxjava3.core.Single
+import io.reactivex.rxjava3.plugins.RxJavaPlugins
+import io.reactivex.rxjava3.schedulers.Schedulers
+import io.reactivex.rxjava3.subjects.SingleSubject
+import kr.co.vividnext.sodalive.common.ApiResponse
+import kr.co.vividnext.sodalive.common.AndroidUtcRelativeTimeTextFormatter
+import kr.co.vividnext.sodalive.common.SharedPreferenceManager
+import kr.co.vividnext.sodalive.v2.creator.channel.data.CreatorChannelRepository
+import kr.co.vividnext.sodalive.v2.creator.channel.fantalk.data.CreatorChannelFanTalkResponse
+import kr.co.vividnext.sodalive.v2.creator.channel.fantalk.data.CreatorChannelFanTalkTabResponse
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
+import org.junit.Assert.assertTrue
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.kotlin.times
+import org.mockito.kotlin.verify
+import org.mockito.kotlin.whenever
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [28], application = Application::class)
+class CreatorChannelFanTalkPaginationTest {
+
+    private val context: Context = ApplicationProvider.getApplicationContext()
+    private lateinit var repository: CreatorChannelRepository
+    private lateinit var viewModel: CreatorChannelFanTalkViewModel
+
+    @Before
+    fun setUp() {
+        setImmediateRxSchedulers()
+        SharedPreferenceManager.resetForTest()
+        SharedPreferenceManager.init(context)
+        SharedPreferenceManager.token = "test-token"
+        SharedPreferenceManager.userId = 10L
+        repository = org.mockito.kotlin.mock()
+        viewModel = CreatorChannelFanTalkViewModel(repository, AndroidUtcRelativeTimeTextFormatter(context))
+    }
+
+    @After
+    fun tearDown() {
+        RxJavaPlugins.reset()
+        RxAndroidPlugins.reset()
+        SharedPreferenceManager.resetForTest()
+    }
+
+    @Test
+    fun `hasNext가 true이면 다음 페이지는 마지막 응답의 page plus 1로 요청하고 append한다`() {
+        stubGetFanTalks(0, Single.just(ApiResponse(true, fanTalkResponse(page = 0, ids = listOf(1L), hasNext = true), null)))
+        stubGetFanTalks(1, Single.just(ApiResponse(true, fanTalkResponse(page = 1, ids = listOf(2L), hasNext = false), null)))
+        viewModel.loadFanTalks(100L, isOwner = false)
+
+        viewModel.loadMore()
+
+        val state = viewModel.fanTalkStateLiveData.requireValue() as CreatorChannelFanTalkUiState.Content
+        assertEquals(1, state.page)
+        assertEquals(listOf(1L, 2L), state.fanTalks.map { it.fanTalkId })
+        assertFalse(state.hasNext)
+        verifyGetFanTalks(page = 1)
+    }
+
+    @Test
+    fun `다음 페이지 로딩 중 중복 load-more 요청은 막고 size 20을 유지한다`() {
+        val pending = SingleSubject.create<ApiResponse<CreatorChannelFanTalkTabResponse>>()
+        stubGetFanTalks(0, Single.just(ApiResponse(true, fanTalkResponse(page = 0, ids = listOf(1L), hasNext = true), null)))
+        stubGetFanTalks(1, pending)
+        viewModel.loadFanTalks(100L, isOwner = false)
+
+        viewModel.loadMore()
+        viewModel.loadMore()
+
+        val loadingState = viewModel.fanTalkStateLiveData.requireValue() as CreatorChannelFanTalkUiState.Content
+        assertTrue(loadingState.isLoadingMore)
+        verifyGetFanTalks(page = 1, times = 1)
+        pending.onSuccess(ApiResponse(true, fanTalkResponse(page = 1, ids = listOf(2L), hasNext = false), null))
+        val loadedState = viewModel.fanTalkStateLiveData.requireValue() as CreatorChannelFanTalkUiState.Content
+        assertEquals(CreatorChannelFanTalkViewModel.DEFAULT_PAGE_SIZE, loadedState.size)
+        assertEquals(listOf(1L, 2L), loadedState.fanTalks.map { it.fanTalkId })
+    }
+
+    @Test
+    fun `다음 페이지 실패는 기존 목록을 유지하고 pagination error message만 설정한다`() {
+        stubGetFanTalks(0, Single.just(ApiResponse(true, fanTalkResponse(page = 0, ids = listOf(1L), hasNext = true), null)))
+        stubGetFanTalks(1, Single.just(ApiResponse(false, null, "failed")))
+        viewModel.loadFanTalks(100L, isOwner = false)
+
+        viewModel.loadMore()
+
+        val state = viewModel.fanTalkStateLiveData.requireValue() as CreatorChannelFanTalkUiState.Content
+        assertEquals(listOf(1L), state.fanTalks.map { it.fanTalkId })
+        assertFalse(state.isLoadingMore)
+        assertEquals("failed", state.paginationErrorMessage)
+    }
+
+    @Test
+    fun `pagination error message는 consume 후 null이 된다`() {
+        stubGetFanTalks(0, Single.just(ApiResponse(true, fanTalkResponse(page = 0, ids = listOf(1L), hasNext = true), null)))
+        stubGetFanTalks(1, Single.just(ApiResponse(false, null, "failed")))
+        viewModel.loadFanTalks(100L, isOwner = false)
+        viewModel.loadMore()
+
+        viewModel.consumePaginationErrorMessage()
+
+        val state = viewModel.fanTalkStateLiveData.requireValue() as CreatorChannelFanTalkUiState.Content
+        assertEquals(null, state.paginationErrorMessage)
+        assertEquals(listOf(1L), state.fanTalks.map { it.fanTalkId })
+    }
+
+    private fun stubGetFanTalks(page: Int, response: Single<ApiResponse<CreatorChannelFanTalkTabResponse>>) {
+        whenever(repository.getFanTalks(100L, page, CreatorChannelFanTalkViewModel.DEFAULT_PAGE_SIZE, "Bearer test-token"))
+            .thenReturn(response)
+    }
+
+    private fun verifyGetFanTalks(page: Int, times: Int? = null) {
+        val verification = times?.let { verify(repository, times(it)) } ?: verify(repository)
+        verification.getFanTalks(100L, page, CreatorChannelFanTalkViewModel.DEFAULT_PAGE_SIZE, "Bearer test-token")
+    }
+
+    private fun setImmediateRxSchedulers() {
+        val trampoline = { _: Scheduler -> Schedulers.trampoline() }
+        RxJavaPlugins.setIoSchedulerHandler(trampoline)
+        RxAndroidPlugins.setInitMainThreadSchedulerHandler { Schedulers.trampoline() }
+        RxAndroidPlugins.setMainThreadSchedulerHandler { Schedulers.trampoline() }
+    }
+
+    private fun fanTalkResponse(page: Int, ids: List<Long>, hasNext: Boolean) = CreatorChannelFanTalkTabResponse(
+        fanTalkCount = ids.size,
+        fanTalks = ids.map { fanTalk(it) },
+        page = page,
+        size = CreatorChannelFanTalkViewModel.DEFAULT_PAGE_SIZE,
+        hasNext = hasNext
+    )
+
+    private fun fanTalk(id: Long) = CreatorChannelFanTalkResponse(
+        fanTalkId = id,
+        writerId = 10L,
+        writerNickname = "writer",
+        writerProfileImageUrl = "profile.png",
+        content = "fan talk $id",
+        createdAtUtc = "2026-06-21T00:00:00Z",
+        creatorReplies = emptyList()
+    )
+
+    private fun <T> LiveData<T>.requireValue(): T? {
+        var value: T? = null
+        val observer = Observer<T> { value = it }
+        observeForever(observer)
+        removeObserver(observer)
+        return value
+    }
+}
--- a/app/src/test/java/kr/co/vividnext/sodalive/v2/creator/channel/fantalk/CreatorChannelFanTalkViewModelTest.kt
+++ b/app/src/test/java/kr/co/vividnext/sodalive/v2/creator/channel/fantalk/CreatorChannelFanTalkViewModelTest.kt
@@ -0,0 +1,156 @@
+package kr.co.vividnext.sodalive.v2.creator.channel.fantalk
+
+import android.app.Application
+import android.content.Context
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.Observer
+import androidx.test.core.app.ApplicationProvider
+import io.reactivex.rxjava3.android.plugins.RxAndroidPlugins
+import io.reactivex.rxjava3.core.Scheduler
+import io.reactivex.rxjava3.core.Single
+import io.reactivex.rxjava3.plugins.RxJavaPlugins
+import io.reactivex.rxjava3.schedulers.Schedulers
+import kr.co.vividnext.sodalive.common.ApiResponse
+import kr.co.vividnext.sodalive.common.AndroidUtcRelativeTimeTextFormatter
+import kr.co.vividnext.sodalive.common.SharedPreferenceManager
+import kr.co.vividnext.sodalive.v2.creator.channel.data.CreatorChannelRepository
+import kr.co.vividnext.sodalive.v2.creator.channel.fantalk.data.CreatorChannelFanTalkResponse
+import kr.co.vividnext.sodalive.v2.creator.channel.fantalk.data.CreatorChannelFanTalkTabResponse
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.kotlin.any
+import org.mockito.kotlin.never
+import org.mockito.kotlin.verify
+import org.mockito.kotlin.whenever
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [28], application = Application::class)
+class CreatorChannelFanTalkViewModelTest {
+
+    private val context: Context = ApplicationProvider.getApplicationContext()
+    private lateinit var repository: CreatorChannelRepository
+    private lateinit var viewModel: CreatorChannelFanTalkViewModel
+
+    @Before
+    fun setUp() {
+        setImmediateRxSchedulers()
+        SharedPreferenceManager.resetForTest()
+        SharedPreferenceManager.init(context)
+        SharedPreferenceManager.token = "test-token"
+        SharedPreferenceManager.userId = 10L
+        repository = org.mockito.kotlin.mock()
+        viewModel = CreatorChannelFanTalkViewModel(repository, AndroidUtcRelativeTimeTextFormatter(context))
+    }
+
+    @After
+    fun tearDown() {
+        RxJavaPlugins.reset()
+        RxAndroidPlugins.reset()
+        SharedPreferenceManager.resetForTest()
+    }
+
+    @Test
+    fun `최초 로드는 page 0 size 20으로 FanTalk API를 호출하고 Content를 emit한다`() {
+        stubGetFanTalks(response = Single.just(ApiResponse(true, fanTalkResponse(ids = listOf(1L)), null)))
+
+        viewModel.loadFanTalks(100L, isOwner = false)
+
+        val state = viewModel.fanTalkStateLiveData.requireValue() as CreatorChannelFanTalkUiState.Content
+        assertEquals(0, state.page)
+        assertEquals(CreatorChannelFanTalkViewModel.DEFAULT_PAGE_SIZE, state.size)
+        assertEquals(listOf(1L), state.fanTalks.map { it.fanTalkId })
+        verifyGetFanTalks()
+    }
+
+    @Test
+    fun `fanTalkCount가 0이면 Empty 상태가 된다`() {
+        stubGetFanTalks(response = Single.just(ApiResponse(true, fanTalkResponse(fanTalkCount = 0, ids = listOf(1L)), null)))
+
+        viewModel.loadFanTalks(100L, isOwner = false)
+
+        val state = viewModel.fanTalkStateLiveData.requireValue() as CreatorChannelFanTalkUiState.Empty
+        assertEquals(0, state.fanTalkCount)
+    }
+
+    @Test
+    fun `표시 가능한 fanTalks가 없으면 Empty 상태가 된다`() {
+        stubGetFanTalks(response = Single.just(ApiResponse(true, fanTalkResponse(ids = emptyList()), null)))
+
+        viewModel.loadFanTalks(100L, isOwner = false)
+
+        assertTrue(viewModel.fanTalkStateLiveData.requireValue() is CreatorChannelFanTalkUiState.Empty)
+    }
+
+    @Test
+    fun `fanTalkCount가 있지만 첫 페이지 목록이 비어 있으면 count를 유지한 Empty 상태가 된다`() {
+        stubGetFanTalks(response = Single.just(ApiResponse(true, fanTalkResponse(fanTalkCount = 5, ids = emptyList()), null)))
+
+        viewModel.loadFanTalks(100L, isOwner = false)
+
+        val state = viewModel.fanTalkStateLiveData.requireValue() as CreatorChannelFanTalkUiState.Empty
+        assertEquals(5, state.fanTalkCount)
+    }
+
+    @Test
+    fun `creatorId가 0 이하이면 API를 호출하지 않는다`() {
+        viewModel.loadFanTalks(0L, isOwner = false)
+
+        verify(repository, never()).getFanTalks(any(), any(), any(), any())
+    }
+
+    private fun stubGetFanTalks(
+        page: Int = 0,
+        response: Single<ApiResponse<CreatorChannelFanTalkTabResponse>>
+    ) {
+        whenever(repository.getFanTalks(100L, page, CreatorChannelFanTalkViewModel.DEFAULT_PAGE_SIZE, "Bearer test-token"))
+            .thenReturn(response)
+    }
+
+    private fun verifyGetFanTalks(page: Int = 0) {
+        verify(repository).getFanTalks(100L, page, CreatorChannelFanTalkViewModel.DEFAULT_PAGE_SIZE, "Bearer test-token")
+    }
+
+    private fun setImmediateRxSchedulers() {
+        val trampoline = { _: Scheduler -> Schedulers.trampoline() }
+        RxJavaPlugins.setIoSchedulerHandler(trampoline)
+        RxAndroidPlugins.setInitMainThreadSchedulerHandler { Schedulers.trampoline() }
+        RxAndroidPlugins.setMainThreadSchedulerHandler { Schedulers.trampoline() }
+    }
+
+    private fun fanTalkResponse(
+        page: Int = 0,
+        fanTalkCount: Int? = null,
+        ids: List<Long>,
+        hasNext: Boolean = false
+    ) = CreatorChannelFanTalkTabResponse(
+        fanTalkCount = fanTalkCount ?: ids.size,
+        fanTalks = ids.map { fanTalk(it) },
+        page = page,
+        size = CreatorChannelFanTalkViewModel.DEFAULT_PAGE_SIZE,
+        hasNext = hasNext
+    )
+
+    private fun fanTalk(id: Long) = CreatorChannelFanTalkResponse(
+        fanTalkId = id,
+        writerId = 10L,
+        writerNickname = "writer",
+        writerProfileImageUrl = "profile.png",
+        content = "fan talk $id",
+        createdAtUtc = "2026-06-21T00:00:00Z",
+        creatorReplies = emptyList()
+    )
+
+    private fun <T> LiveData<T>.requireValue(): T? {
+        var value: T? = null
+        val observer = Observer<T> { value = it }
+        observeForever(observer)
+        removeObserver(observer)
+        return value
+    }
+}