test: refactor MainScreenViewModel tests to use repository mocks instead of fake context

app/src/test/java/com/example/esp32aldldashboard/ui/main/MainScreenViewModelTest.kt

@@ -1,29 +1,49 @@
 package com.example.esp32aldldashboard.ui.main
 
-import android.content.Context
-import android.content.ContextWrapper
 import com.example.esp32aldldashboard.bluetooth.ConnectionState
+import com.example.esp32aldldashboard.repository.SettingsRepository
+import com.example.esp32aldldashboard.repository.TelemetryRepository
+import io.mockk.*
 import junit.framework.TestCase.assertEquals
 import junit.framework.TestCase.assertFalse
 import junit.framework.TestCase.assertTrue
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.test.runCurrent
 import kotlinx.coroutines.test.runTest
+import org.junit.Before
 import org.junit.Test
 
 class MainScreenViewModelTest {
 
-    private class FakeContext : ContextWrapper(null) {
-        override fun getApplicationContext(): Context {
-            return this
-        }
-        override fun getSystemService(name: String): Any? {
-            return null
+    private val telemetryRepository = mockk<TelemetryRepository>(relaxed = true)
+    private val settingsRepository = mockk<SettingsRepository>(relaxed = true)
+    private val isCelsiusFlow = MutableStateFlow(false)
+
+    @Before
+    fun setUp() {
+        // Clear mocks
+        clearAllMocks()
+        
+        // Stub telemetry repository flows
+        every { telemetryRepository.connectionState } returns MutableStateFlow(ConnectionState.DISCONNECTED)
+        every { telemetryRepository.latestFrame } returns MutableStateFlow(null)
+        every { telemetryRepository.rawHexLog } returns MutableStateFlow(emptyList())
+        every { telemetryRepository.errorMessage } returns MutableStateFlow("")
+        every { telemetryRepository.framesReceived } returns MutableStateFlow(0)
+        every { telemetryRepository.parseErrors } returns MutableStateFlow(0)
+        every { telemetryRepository.currentFrameRate } returns MutableStateFlow(0)
+        
+        // Stub settings repository
+        isCelsiusFlow.value = false
+        every { settingsRepository.isCelsiusFlow } returns isCelsiusFlow
+        coEvery { settingsRepository.setIsCelsius(any()) } answers {
+            isCelsiusFlow.value = firstArg()
         }
     }
 
     @Test
     fun testInitialStates() = runTest {
-        val context = FakeContext()
-        val viewModel = MainScreenViewModel(context)
+        val viewModel = MainScreenViewModel(telemetryRepository, settingsRepository)
         
         assertEquals(ConnectionState.DISCONNECTED, viewModel.connectionState.value)
         assertEquals(null, viewModel.latestFrame.value)
@@ -32,13 +52,22 @@ class MainScreenViewModelTest {
 
     @Test
     fun testToggleTemperatureUnit() = runTest {
-        val context = FakeContext()
-        val viewModel = MainScreenViewModel(context)
+        val viewModel = MainScreenViewModel(telemetryRepository, settingsRepository)
         
+        // Wait for stateIn initialization
+        runCurrent()
         assertFalse(viewModel.isCelsius.value)
+        
         viewModel.toggleTemperatureUnit()
+        runCurrent() // Wait for viewmodel scope coroutine to execute settingsRepository.setIsCelsius
+        runCurrent() // Wait for settingsRepository update flow to propagate back through stateIn
+        
         assertTrue(viewModel.isCelsius.value)
+        
         viewModel.toggleTemperatureUnit()
+        runCurrent()
+        runCurrent()
+        
         assertFalse(viewModel.isCelsius.value)
     }
 }