add tests for details view model

feature/details/src/commonTest/kotlin/com/theophiluskibet/calorees/details/screens/DetailsViewModelTest.kt

@@ -1,15 +1,21 @@
 package com.theophiluskibet.calorees.details.screens
 
 import com.theophilus.kibet.caloree.data.sources.CaloreeRepositoryImpl
+import com.theophiluskibet.calorees.details.utils.DetailsUiState
 import com.theophiluskibet.calorees.details.utils.FakeCaloreeRepository
+import com.theophiluskibet.calorees.details.utils.searchData
 import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.first
+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 kotlin.test.AfterTest
 import kotlin.test.BeforeTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
+import kotlin.test.assertTrue
 
 class DetailsViewModelTest {
 
@@ -18,7 +24,7 @@ class DetailsViewModelTest {
 
     @BeforeTest
     fun setup() {
-        Dispatchers.setMain(Dispatchers.Unconfined)
+        Dispatchers.setMain(StandardTestDispatcher())
         detailsViewModel = DetailsViewModel(repository = repository)
     }
 
@@ -28,9 +34,56 @@ class DetailsViewModelTest {
     }
 
     @Test
-    fun `sample test`() = runTest {
-        val data = repository.searchCalories("meat")
-        detailsViewModel.getCaloreeDetails("meat")
-        assertEquals("meat", data.first().name)
+    fun `given DetailsViewModel- initial details ui state is default`() = runTest {
+        assertEquals(detailsViewModel.caloreeUiState.value, DetailsUiState.Default)
     }
+
+    @Test
+    fun `given string of food - when getCalireeDetails is invoked - then details ui state is loading`() =
+        runTest {
+            // given
+            val food = "rice"
+
+            // when
+            detailsViewModel.getCaloreeDetails(food)
+
+            // then
+            assertEquals(DetailsUiState.Loading, detailsViewModel.caloreeUiState.value)
+        }
+
+    @Test
+    fun `given string of food - when getCalireeDetails is success - then details ui state is success with data`() =
+        runTest {
+            // given
+            val food = "rice"
+
+            // when
+            detailsViewModel.getCaloreeDetails(food)
+            advanceUntilIdle()
+
+            // then
+            assertEquals(
+                DetailsUiState.Success(data = searchData.first()),
+                detailsViewModel.caloreeUiState.value
+            )
+        }
+
+    @Test
+    fun `given string of food - when getCalireeDetails is error - then details ui state is error with message`() =
+        runTest {
+            // simulate error in the repository
+            repository.shouldThrowError = true
+            // given
+            val food = "rice"
+
+            // when
+            detailsViewModel.getCaloreeDetails(food)
+            advanceUntilIdle()
+
+            // then
+            assertEquals(
+                DetailsUiState.Error(errorMessage = "An error occured"),
+                detailsViewModel.caloreeUiState.value
+            )
+        }
 }

feature/details/src/commonTest/kotlin/com/theophiluskibet/calorees/details/utils/FakeCaloreeRepository.kt

@@ -5,23 +5,16 @@ import com.theophilus.kibet.caloree.data.sources.CaloreeRepository
 import kotlinx.coroutines.flow.Flow
 
 class FakeCaloreeRepository : CaloreeRepository {
+    var shouldThrowError = false
     override suspend fun searchCalories(query: String): List<Caloree> {
-        return listOf(
-            Caloree(
-                name = "meat",
-                calories = 20.0,
-                carbohydratesTotalGrams = 20.0,
-                cholesterolMilliGrams = 100,
-                fatSaturatedGrams = 30.0,
-                fatTotalGrams = 44.0,
-                fiberGrams = 30.0,
-                potassiumMilliGrams = 261,
-                proteinGrams = 104.0,
-                servingSizeGrams = 100.0,
-                sodiumMilliGrams = 127,
-                sugarGrams = 68.0,
-            )
-        )
+        if (shouldThrowError) {
+            throw RuntimeException("An error occured")
+        }
+        return searchData
+    }
+
+    fun simulateError(): List<Caloree> {
+        throw Throwable(message = "Error occured")
     }
 
     override suspend fun getSavedCalories(): Flow<List<Caloree>> {
@@ -31,4 +24,21 @@ class FakeCaloreeRepository : CaloreeRepository {
     override suspend fun getCalorieDetails(food: String): Flow<Caloree> {
         TODO("Not yet implemented")
     }
-}
+}
+
+val searchData = listOf(
+    Caloree(
+        name = "meat",
+        calories = 20.0,
+        carbohydratesTotalGrams = 20.0,
+        cholesterolMilliGrams = 100,
+        fatSaturatedGrams = 30.0,
+        fatTotalGrams = 44.0,
+        fiberGrams = 30.0,
+        potassiumMilliGrams = 261,
+        proteinGrams = 104.0,
+        servingSizeGrams = 100.0,
+        sodiumMilliGrams = 127,
+        sugarGrams = 68.0,
+    )
+)