Keep shell state reads safe in read-only snapshots

app/src/test/java/org/justinvisser/wolfskin/tv/DiscoverSnapshotReadTest.kt

@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0-only
+package org.justinvisser.wolfskin.tv
+
+import android.app.Application
+import androidx.activity.ComponentActivity
+import androidx.compose.ui.test.junit4.createAndroidComposeRule
+import kotlinx.coroutines.runBlocking
+import org.junit.Assert.*
+import org.junit.Rule
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.justinvisser.wolfskin.conductarr.MemoryCacheStore
+import org.justinvisser.wolfskin.design.*
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+
+/** No drawn screen may prewarm memory before the production Discover observer starts. */
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [34], application = Application::class)
+class DiscoverSnapshotReadTest {
+    @get:Rule val rule = createAndroidComposeRule<ComponentActivity>()
+
+    @Test fun signedInHostObservesFreshShellThroughTheRealAsyncProvider() {
+        FakeConductarr().use { fake ->
+            ConductarrSession(MemoryCacheStore()).use { session ->
+                session.select("server:shared", SHARED_TOKEN, fake.url)
+                runBlocking { session.authenticate() }
+                val identity = requireNotNull(session.identity.value)
+                assertTrue(identity.signedIn)
+                val shell = ShellState(listOf(ShellPerson("shared", "Shared", "S", true)), "shared")
+                lateinit var current: DiscoverState
+                rule.setContent {
+                    current = rememberDiscoverState(shell, shell::enterDestination, {}, identity = identity, fixtures = false,
+                        loadFixture = { error("Production observer must not load fixtures") })
+                }
+                rule.waitUntil(30_000) {
+                    org.robolectric.Shadows.shadowOf(android.os.Looper.getMainLooper()).idle()
+                    current.snapshot.status == DiscoverStatus.Ready
+                }
+                rule.waitForIdle()
+                rule.runOnIdle {
+                    assertTrue(fake.calls.any { it.url.encodedPath.endsWith("/feed") })
+                    assertEquals(0, current.focusedRow)
+                    assertEquals(0, current.column)
+                    current.focus(current.firstShelf)
+                }
+                rule.waitForIdle()
+                rule.runOnIdle {
+                    assertNotNull(current.focusedLane)
+                    assertEquals(current.firstShelf, current.focusedRow)
+                    assertEquals(0, current.column)
+                }
+            }
+        }
+    }
+}