test: add unit tests for use cases and ViewModel, add Compose UI test

app/src/test/java/com/radiola/domain/usecase/SearchTrackInServiceUseCaseTest.kt

@@ -0,0 +1,29 @@
+package com.radiola.domain.usecase
+
+import com.radiola.domain.model.DeeplinkService
+import com.radiola.domain.model.Track
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class SearchTrackInServiceUseCaseTest {
+
+    private val useCase = SearchTrackInServiceUseCase()
+
+    @Test
+    fun `invoke returns correct Yandex Music URL`() {
+        val track = Track("Artist", "Song", null, "Record")
+        val url = useCase(track, DeeplinkService.YANDEX)
+
+        assertTrue(url.startsWith("https://music.yandex.ru/search"))
+        assertTrue(url.contains("Artist"))
+        assertTrue(url.contains("Song"))
+    }
+
+    @Test
+    fun `invoke returns correct Spotify URL`() {
+        val track = Track("Artist", "Song", null, "Record")
+        val url = useCase(track, DeeplinkService.SPOTIFY)
+
+        assertTrue(url.startsWith("https://open.spotify.com/search"))
+    }
+}

app/src/test/java/com/radiola/domain/usecase/ToggleFavoriteUseCaseTest.kt

@@ -0,0 +1,37 @@
+package com.radiola.domain.usecase
+
+import com.radiola.domain.model.Station
+import com.radiola.domain.repository.FavoritesRepository
+import io.mockk.coEvery
+import io.mockk.coVerify
+import io.mockk.mockk
+import kotlinx.coroutines.flow.flowOf
+import kotlinx.coroutines.test.runTest
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class ToggleFavoriteUseCaseTest {
+
+    private val favoritesRepository: FavoritesRepository = mockk(relaxed = true)
+    private val useCase = ToggleFavoriteUseCase(favoritesRepository)
+
+    @Test
+    fun `invoke adds favorite when not favorite`() = runTest {
+        val station = Station(1, "Record", "rr", "", "", "", emptyList(), 0)
+        coEvery { favoritesRepository.isFavorite(station.id) } returns flowOf(false)
+
+        useCase(station)
+
+        coVerify { favoritesRepository.addFavorite(station) }
+    }
+
+    @Test
+    fun `invoke removes favorite when already favorite`() = runTest {
+        val station = Station(1, "Record", "rr", "", "", "", emptyList(), 0)
+        coEvery { favoritesRepository.isFavorite(station.id) } returns flowOf(true)
+
+        useCase(station)
+
+        coVerify { favoritesRepository.removeFavorite(station.id) }
+    }
+}

app/src/test/java/com/radiola/ui/stations/StationsViewModelTest.kt

@@ -0,0 +1,69 @@
+package com.radiola.ui.stations
+
+import com.radiola.domain.model.Station
+import com.radiola.domain.usecase.GetStationsUseCase
+import com.radiola.domain.usecase.PlayStationUseCase
+import com.radiola.domain.usecase.ToggleFavoriteUseCase
+import io.mockk.coVerify
+import io.mockk.every
+import io.mockk.mockk
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.flowOf
+import kotlinx.coroutines.test.StandardTestDispatcher
+import kotlinx.coroutines.test.advanceUntilIdle
+import kotlinx.coroutines.test.resetMain
+import kotlinx.coroutines.test.runTest
+import kotlinx.coroutines.test.setMain
+import org.junit.After
+import org.junit.Assert.assertEquals
+import org.junit.Before
+import org.junit.Test
+
+@OptIn(ExperimentalCoroutinesApi::class)
+class StationsViewModelTest {
+
+    private val testDispatcher = StandardTestDispatcher()
+    private val getStationsUseCase: GetStationsUseCase = mockk()
+    private val playStationUseCase: PlayStationUseCase = mockk(relaxed = true)
+    private val toggleFavoriteUseCase: ToggleFavoriteUseCase = mockk(relaxed = true)
+
+    @Before
+    fun setup() {
+        Dispatchers.setMain(testDispatcher)
+        every { getStationsUseCase() } returns flowOf(
+            listOf(
+                Station(1, "Record", "rr", "", "", "Trans", listOf("trans"), 0),
+                Station(2, "Deep", "deep", "", "", "House", listOf("house"), 1)
+            )
+        )
+    }
+
+    @After
+    fun tearDown() {
+        Dispatchers.resetMain()
+    }
+
+    @Test
+    fun `stations filtered by search query`() = runTest {
+        val viewModel = StationsViewModel(getStationsUseCase, playStationUseCase, toggleFavoriteUseCase)
+        advanceUntilIdle()
+
+        viewModel.onSearchQueryChange("Record")
+        advanceUntilIdle()
+
+        assertEquals(1, viewModel.stations.value.size)
+        assertEquals("Record", viewModel.stations.value[0].name)
+    }
+
+    @Test
+    fun `playStation calls use case`() = runTest {
+        val viewModel = StationsViewModel(getStationsUseCase, playStationUseCase, toggleFavoriteUseCase)
+        val station = Station(1, "Record", "rr", "", "", "", emptyList(), 0)
+
+        viewModel.playStation(station)
+        advanceUntilIdle()
+
+        coVerify { playStationUseCase(station) }
+    }
+}