Add swift-snapshot-testing + test (#229)

Author: trevor-e

ios/HackerNews.xcodeproj/project.pbxproj

@@ -6,8 +6,8 @@
 //
 
 import Foundation
-import SwiftUI
 import SnapshotPreferences
+import SwiftUI
 
 struct PreviewVariants<Content: View>: View {
   let content: Content
@@ -31,7 +31,7 @@ struct PreviewVariants<Content: View>: View {
         .navigationBarHidden(true)
         .previewDevice("iPhone 11 Pro Max")
         .previewDisplayName("iPhone 11 Pro Max, dark mode")
-      
+
       self.content
         .environment(\.colorScheme, .light)
         .preferredColorScheme(.light)
@@ -45,7 +45,7 @@ struct PreviewVariants<Content: View>: View {
         .navigationBarHidden(true)
         .previewDevice("iPhone 8")
         .previewDisplayName("iPhone 8, dark mode")
-      
+
       self.content
         .environment(\.colorScheme, .light)
         .preferredColorScheme(.light)
@@ -59,7 +59,7 @@ struct PreviewVariants<Content: View>: View {
         .navigationBarHidden(true)
         .previewDevice("iPad Air (5th generation)")
         .previewDisplayName("iPad Air, dark mode")
-      
+
       self.content
         .environment(\.colorScheme, .light)
         .preferredColorScheme(.light)
@@ -72,12 +72,20 @@ struct PreviewVariants<Content: View>: View {
 }
 
 struct PreviewHelpers {
-  static func withNavigationView(@ViewBuilder content: () -> some View) -> some View {
+  private static var referenceTimestamp: Int64 {
+    let calendar = Calendar.current
+    let oneYearAgo = calendar.date(byAdding: .hour, value: -1, to: Date())!
+    return Int64(oneYearAgo.timeIntervalSince1970)
+  }
+
+  static func withNavigationView(@ViewBuilder content: () -> some View)
+    -> some View
+  {
     NavigationStack {
       ZStack {
         HNColors.background
           .ignoresSafeArea()
-        
+
         content()
       }
       .toolbarColorScheme(.dark, for: .navigationBar)
@@ -92,11 +100,13 @@ struct PreviewHelpers {
     }
   }
 
-  static func makeFakeStory(index: Int64 = 0, descendants: Int = 0, kids: [Int64]? = nil) -> Story {
+  static func makeFakeStory(
+    index: Int64 = 0, descendants: Int = 0, kids: [Int64]? = nil
+  ) -> Story {
     return Story(
       id: index,
       by: "dang",
-      time: Int64(Date().timeIntervalSince1970) - Int64(index),
+      time: referenceTimestamp - (index * 3600),  // Each story 1 hour apart
       type: .story,
       title: "Test story \(index)",
       text: "Test story body \(index)",
@@ -111,22 +121,24 @@ struct PreviewHelpers {
     Comment(
       id: 1,
       by: "dang",
-      time: Int64(Date.now.timeIntervalSince1970),
+      time: referenceTimestamp,
       type: .comment,
       text: """
-  Totally useless commentary:
-  It makes me deeply happy to hear success stories like this for a project that's moving in the correctly opposite direction to that of the rest of the world.
+        Totally useless commentary:
+        It makes me deeply happy to hear success stories like this for a project that's moving in the correctly opposite direction to that of the rest of the world.
 
-  Engildification. Of which there should be more!
+        Engildification. Of which there should be more!
 
-  My soul was also satisfied by the Sleeping At Night post which, along with the recent "Lie Still in Bed" article, makes for very simple options to attempt to fix sleep (discipline) issues
-  """,
+        My soul was also satisfied by the Sleeping At Night post which, along with the recent "Lie Still in Bed" article, makes for very simple options to attempt to fix sleep (discipline) issues
+        """,
       parent: nil,
       kids: nil
     )
   }
 
-  static func makeFakeFlattenedComment(comment: Comment = makeFakeComment(), depth: Int = 0) -> FlattenedComment {
+  static func makeFakeFlattenedComment(
+    comment: Comment = makeFakeComment(), depth: Int = 0
+  ) -> FlattenedComment {
     FlattenedComment(comment: comment, depth: depth)
   }
 }

ios/HackerNews.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved

@@ -0,0 +1,128 @@
+//
+//  SwiftSnapshotTest.swift
+//  HackerNews
+//
+//  Created by Trevor Elkins on 11/19/24.
+//
+
+import SnapshotTesting
+import SwiftUI
+import XCTest
+
+@testable import HackerNews
+
+final class SwiftSnapshotTest: XCTestCase {
+
+  var appViewModel: AppViewModel!
+
+  @MainActor override func setUp() {
+    super.setUp()
+    appViewModel = AppViewModel()
+  }
+
+  override func tearDown() {
+    appViewModel = nil
+    super.tearDown()
+  }
+
+  override func invokeTest() {
+    // Change the record mode when updating tests
+    withSnapshotTesting(record: .never) {
+      super.invokeTest()
+    }
+  }
+
+  func testLoginScreen() {
+    let view = LoginScreen(appState: appViewModel)
+
+    let devices = [
+      ("iPhone SE", ViewImageConfig.iPhoneSe),
+      ("iPhone 12", ViewImageConfig.iPhone12),
+      ("iPhone 13 Pro", ViewImageConfig.iPhone13Pro),
+    ]
+
+    for (name, config) in devices {
+      assertSnapshot(
+        of: view.toVC(),
+        as: .image(on: config),
+        named: "LoginScreen-\(name)"
+      )
+      assertSnapshot(
+        of: view.toVC(),
+        as: .image(on: config, traits: .init(userInterfaceStyle: .dark)),
+        named: "LoginScreen-\(name)-DarkMode"
+      )
+    }
+  }
+
+  @MainActor func testPostListScreen() {
+    // Test default state
+    let defaultView = PostListScreen(appState: appViewModel)
+
+    // Test loading state
+    let loadingViewModel = AppViewModel()
+    loadingViewModel.authState = .loggedIn
+    loadingViewModel.storiesState = .loading
+    let loadingView = PostListScreen(appState: loadingViewModel)
+
+    // Test loaded state with posts
+    let loadedViewModel = AppViewModel()
+    loadedViewModel.authState = .loggedIn
+    loadedViewModel.storiesState = .loaded(
+      stories: PreviewHelpers.makeFakeStories())
+    let loadedView = PostListScreen(appState: loadedViewModel)
+
+    let devices = [
+      ("iPhone SE", ViewImageConfig.iPhoneSe),
+      ("iPhone 12", ViewImageConfig.iPhone12),
+      ("iPhone 13 Pro", ViewImageConfig.iPhone13Pro),
+    ]
+
+    // Test each state on different devices
+    for (name, config) in devices {
+      // Default state
+      assertSnapshot(
+        of: defaultView.toVC(),
+        as: .image(on: config),
+        named: "PostListScreen-Default-\(name)"
+      )
+      assertSnapshot(
+        of: defaultView.toVC(),
+        as: .image(on: config, traits: .init(userInterfaceStyle: .dark)),
+        named: "PostListScreen-Default-\(name)-DarkMode"
+      )
+
+      // Loading state
+      assertSnapshot(
+        of: loadingView.toVC(),
+        as: .image(on: config),
+        named: "PostListScreen-Loading-\(name)"
+      )
+      assertSnapshot(
+        of: loadingView.toVC(),
+        as: .image(on: config, traits: .init(userInterfaceStyle: .dark)),
+        named: "PostListScreen-Loading-\(name)-DarkMode"
+      )
+
+      // Loaded state with posts
+      assertSnapshot(
+        of: loadedView.toVC(),
+        as: .image(on: config),
+        named: "PostListScreen-LoadedPosts-\(name)"
+      )
+      assertSnapshot(
+        of: loadedView.toVC(),
+        as: .image(on: config, traits: .init(userInterfaceStyle: .dark)),
+        named: "PostListScreen-LoadedPosts-\(name)-DarkMode"
+      )
+    }
+  }
+}
+
+extension View {
+  fileprivate func toVC() -> UIViewController {
+    let hostingController = UIHostingController(rootView: self)
+    hostingController.view.frame = UIScreen.main.bounds
+    return hostingController
+  }
+}