Merge pull request #211 from myofficework000/CurrencyConverter

added test cases for CurrencyConverterViewModel

app/src/main/java/com/example/jetpack_compose_all_in_one/demos/currency_converter/presentation/view/CurrencyConverterScreen.kt

@@ -45,7 +45,7 @@ fun CurrencyFromToScreen(viewModel: CurrencyViewModel = hiltViewModel()) {
                 text = it
                 viewModel.handleIntent(CurrencyIntent.CurrencyInputChanged(it))
             },
-            label = { Text("Enter EUR Amount") },
+            placeholder = { Text("Enter EUR Amount") },
             modifier = Modifier.fillMaxWidth()
         )
 

app/src/test/java/com/example/jetpack_compose_all_in_one/viewmodel/CurrencyConverterViewModelTest.kt

@@ -0,0 +1,65 @@
+package com.example.jetpack_compose_all_in_one.viewmodel
+
+import com.example.jetpack_compose_all_in_one.demos.currency_converter.data.dto.CurrencyResponse
+import com.example.jetpack_compose_all_in_one.demos.currency_converter.data.repository.CurrencyRepository
+import com.example.jetpack_compose_all_in_one.demos.currency_converter.presentation.intent.CurrencyIntent
+import com.example.jetpack_compose_all_in_one.demos.currency_converter.presentation.intent.CurrencyState
+import com.example.jetpack_compose_all_in_one.demos.currency_converter.presentation.viewmodel.CurrencyViewModel
+import io.mockk.coEvery
+import io.mockk.mockk
+import junit.framework.TestCase
+import junit.framework.TestCase.assertEquals
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.delay
+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.Before
+import org.junit.Test
+
+class CurrencyConverterViewModelTest {
+
+    private val testDispatcher = StandardTestDispatcher()
+    private val repository = mockk<CurrencyRepository>(relaxed = true)
+    private lateinit var viewModel: CurrencyViewModel
+
+    @Before
+    fun setup() {
+        Dispatchers.setMain(testDispatcher)
+        viewModel = CurrencyViewModel(repository)
+    }
+
+    @After
+    fun tearDown(){
+        Dispatchers.resetMain()
+    }
+
+    @OptIn(ExperimentalCoroutinesApi::class)
+    @Test
+    fun `Given user input, When fetching currency data, Then state is success and contains converted value`() = runTest {
+        val expectedResponse = CurrencyResponse("2010-01-01", 130.0)
+        coEvery { repository.getEURToJPY() } returns Result.success(expectedResponse)
+
+        viewModel.handleIntent(CurrencyIntent.CurrencyInputChanged("100"))
+        advanceUntilIdle()
+
+        val actualState = viewModel.state.value
+        val expectedState = CurrencyState.Success(expectedResponse)
+        assertEquals(expectedState, actualState)
+    }
+
+    @OptIn(ExperimentalCoroutinesApi::class)
+    @Test
+    fun `Given user input, When encountering network exception, Then state is Error`() = runTest {
+        coEvery { repository.getEURToJPY() } returns Result.failure(RuntimeException("Network Error"))
+
+        viewModel.handleIntent(CurrencyIntent.CurrencyInputChanged("100"))
+        advanceUntilIdle()
+
+        TestCase.assertTrue(viewModel.state.value is CurrencyState.Error)
+    }
+}