Add test-mode animation switch for UI tests

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Unreleased (develop)
 
+- added: iOS debug-build `EdgeTestAnimations` switch to turn off or speed up animations and freeze spinners in UI tests
 - added: `YOLO_OTP_KEY` env setting, which lets auto-login reach a 2FA-protected account on a device that has no login stash for it yet.
 - added: Slow-sync explainer card on Bitcoin-family wallets with a long transaction history.
 - added: Logbox disable option to env.json

ios/edge/SceneDelegate.swift

@@ -37,6 +37,7 @@ class SceneDelegate: UIResponder, UIWindowSceneDelegate {
     let window = UIWindow(windowScene: windowScene)
     self.window = window
     appDelegate.window = window
+    Self.applyTestAnimations(to: window)
 
     // A reconnecting scene already has React Native running, and starting it
     // again would mount a second copy of the app, so reuse the root view
@@ -149,6 +150,27 @@ class SceneDelegate: UIResponder, UIWindowSceneDelegate {
     }
   }
 
+  /**
+   * Test-mode animation switch for automated UI runs, read from the
+   * `EdgeTestAnimations` user default (the `-EdgeTestAnimations off|fast`
+   * launch argument). `off` makes UIKit animations complete immediately and
+   * `fast` runs the window's Core Animation clock 100x. Either value freezes
+   * activity spinners. Debug builds only. Edge addition.
+   */
+  private static func applyTestAnimations(to window: UIWindow) {
+    #if DEBUG
+    switch UserDefaults.standard.string(forKey: "EdgeTestAnimations") {
+    case "off":
+      UIView.setAnimationsEnabled(false)
+    case "fast":
+      window.layer.speed = 100
+    default:
+      return
+    }
+    UIActivityIndicatorView.freezeForTests()
+    #endif
+  }
+
   /**
    * Rebuilds the launch options React Native expects from the scene's
    * connection options.
@@ -181,3 +203,34 @@ class SceneDelegate: UIResponder, UIWindowSceneDelegate {
     return [:]
   }
 }
+
+#if DEBUG
+/**
+ * Test-mode spinners stay visible but stop turning, so a loading screen
+ * settles for screenshot comparisons. Edge addition.
+ */
+extension UIActivityIndicatorView {
+  private static let swapStartAnimating: Void = {
+    guard
+      let original = class_getInstanceMethod(
+        UIActivityIndicatorView.self, #selector(startAnimating)),
+      let frozen = class_getInstanceMethod(
+        UIActivityIndicatorView.self, #selector(frozenStartAnimating))
+    else {
+      return
+    }
+    method_exchangeImplementations(original, frozen)
+  }()
+
+  /** Swaps `startAnimating` once, however many scenes connect. */
+  static func freezeForTests() {
+    _ = swapStartAnimating
+  }
+
+  /** After the swap, the inner call runs UIKit's own `startAnimating`. */
+  @objc private func frozenStartAnimating() {
+    frozenStartAnimating()
+    layer.speed = 0
+  }
+}
+#endif

src/components/App.tsx

@@ -5,9 +5,11 @@ import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
 import * as React from 'react'
 import { StyleSheet } from 'react-native'
 import { GestureHandlerRootView } from 'react-native-gesture-handler'
+import { ReducedMotionConfig, ReduceMotion } from 'react-native-reanimated'
 import { SafeAreaProvider } from 'react-native-safe-area-context'
 
 import { useHandler } from '../hooks/useHandler'
+import { getTestAnimationsMode } from '../util/testAnimations'
 import { CrashScene } from './scenes/CrashScene'
 import { EdgeCoreManager } from './services/EdgeCoreManager'
 import { QuickActionsManager } from './services/QuickActionsManager'
@@ -23,6 +25,10 @@ const queryClient = new QueryClient({
   }
 })
 
+// Automated UI runs finish Reanimated loops (shimmers, chart pulses) after
+// one cycle so the screen can settle between steps:
+const testAnimationsMode = getTestAnimationsMode()
+
 const MainApp: React.FC = () => {
   const handleBeforeCapture = useHandler((scope: Scope) => {
     scope.setLevel('fatal')
@@ -34,6 +40,9 @@ const MainApp: React.FC = () => {
       <SafeAreaProvider>
         <ThemeProvider>
           <GestureHandlerRootView style={StyleSheet.absoluteFill}>
+            {testAnimationsMode == null ? null : (
+              <ReducedMotionConfig mode={ReduceMotion.Always} />
+            )}
             <ErrorBoundary
               beforeCapture={handleBeforeCapture}
               fallback={<CrashScene />}

src/util/testAnimations.ts

@@ -0,0 +1,15 @@
+import { Platform, Settings } from 'react-native'
+
+export type TestAnimationsMode = 'off' | 'fast'
+
+/**
+ * Test-mode animation switch for automated UI runs, read from the
+ * `EdgeTestAnimations` user default (the `-EdgeTestAnimations off|fast`
+ * launch argument, or a value the test harness wrote to the simulator).
+ * Debug builds on iOS only; always null elsewhere.
+ */
+export const getTestAnimationsMode = (): TestAnimationsMode | null => {
+  if (!__DEV__ || Platform.OS !== 'ios') return null
+  const mode: unknown = Settings.get('EdgeTestAnimations')
+  return mode === 'off' || mode === 'fast' ? mode : null
+}