feat(#365): add pin support for models with pinned section at top (#414)

* feat(#365): add pin support for models with pinned section at top

* fix(#365): stub Pinned Models methods in E2eIntegrationTest

* fix(#365): use state flow for pin/unpin, add max cap, add ViewModel tests

---------

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/androidTest/java/com/m57/hermescontrol/ui/model/ModelScreenTest.kt

@@ -0,0 +1,100 @@
+package com.m57.hermescontrol.ui.model
+
+import androidx.compose.ui.test.assertIsDisplayed
+import androidx.compose.ui.test.junit4.createComposeRule
+import androidx.compose.ui.test.onNodeWithText
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import androidx.test.filters.MediumTest
+import com.m57.hermescontrol.data.model.ModelProvider
+import com.m57.hermescontrol.data.model.PinnedModel
+import io.mockk.every
+import io.mockk.mockk
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import org.junit.Before
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+
+@RunWith(AndroidJUnit4::class)
+@MediumTest
+class ModelScreenTest {
+    @get:Rule
+    val composeTestRule = createComposeRule()
+
+    private val mockViewModel = mockk<ModelViewModel>(relaxed = true)
+    private val uiStateFlow = MutableStateFlow(ModelUiState())
+
+    @Before
+    fun setUp() {
+        every { mockViewModel.uiState } returns uiStateFlow.asStateFlow()
+    }
+
+    @Test
+    fun modelScreen_pinnedSectionHidden_whenNoPinnedModels() {
+        uiStateFlow.value =
+            ModelUiState(
+                providers =
+                    listOf(
+                        ModelProvider(
+                            slug = "openai",
+                            name = "OpenAI",
+                            is_current = true,
+                            is_user_defined = false,
+                            models = listOf("gpt-4"),
+                            total_models = 1,
+                            source = null,
+                            authenticated = true,
+                            auth_type = null,
+                            warning = null,
+                        ),
+                    ),
+                pinnedModels = emptyList(),
+            )
+
+        composeTestRule.setContent {
+            ModelScreen(
+                onOpenDrawer = {},
+                viewModel = mockViewModel,
+            )
+        }
+
+        composeTestRule.onNodeWithText("Pinned Models").assertDoesNotExist()
+    }
+
+    @Test
+    fun modelScreen_rendersPinnedModels_whenPresent() {
+        uiStateFlow.value =
+            ModelUiState(
+                providers =
+                    listOf(
+                        ModelProvider(
+                            slug = "openai",
+                            name = "OpenAI",
+                            is_current = true,
+                            is_user_defined = false,
+                            models = listOf("gpt-4"),
+                            total_models = 1,
+                            source = null,
+                            authenticated = true,
+                            auth_type = null,
+                            warning = null,
+                        ),
+                    ),
+                pinnedModels =
+                    listOf(
+                        PinnedModel(providerSlug = "openai", modelName = "gpt-4"),
+                    ),
+            )
+
+        composeTestRule.setContent {
+            ModelScreen(
+                onOpenDrawer = {},
+                viewModel = mockViewModel,
+            )
+        }
+
+        composeTestRule.onNodeWithText("Pinned Models").assertIsDisplayed()
+        composeTestRule.onNodeWithText("gpt-4").assertIsDisplayed()
+    }
+}