Add tests

Package.swift

@@ -4,62 +4,109 @@
 import PackageDescription
 
 let package = Package(
-    name: "SnapshotPreviews",
-    platforms: [.iOS(.v15), .macOS(.v12), .watchOS(.v9)],
-    products: [
-        // Products define the executables and libraries a package produces, making them visible to other packages.
-        .library(
-          name: "PreviewGallery",
-          type: .static, // Replace this to build dynamic
-          targets: ["PreviewGallery"]),
-        // Test library to import in your XCTest target.
-        // This is the only library that depends on XCTest.framework
-        .library(
-          name: "SnapshottingTests",
-          type: .static, // Replace this to build dynamic
-          targets: ["SnapshottingTests"]),
-        // Link the main app to this target to use custom snapshot settings
-        // This lib does not get inserted when running tests to avoid
-        // duplicate symbols.
-        .library(
-          name: "SnapshotPreferences",
-          targets: ["SnapshotPreferences"]),
-        // Core functionality for snapshotting exported from the internal package
-        .library(
-          name: "SnapshotPreviewsCore",
-          targets: ["SnapshotPreviewsCore"]),
-        // Dynamic library that your main app will have inserted to generate previews
-        .library(
-          name: "Snapshotting",
-          type: .dynamic,
-          targets: ["Snapshotting"]),
-    ],
-    dependencies: [
-      .package(url: "https://github.com/swhitty/FlyingFox.git", exact: "0.16.0"),
-      .package(url: "https://github.com/EmergeTools/AccessibilitySnapshot.git", exact: "1.0.2"),
-      .package(url: "https://github.com/EmergeTools/SimpleDebugger.git", exact: "1.0.0"),
-    ],
-    targets: [
-        // Targets are the basic building blocks of a package, defining a module or a test suite.
-        // Targets can depend on other targets in this package and products from dependencies.
-        // Target that provides the XCTest
-      .target(name: "SnapshottingTestsObjc", dependencies: [.product(name: "SimpleDebugger", package: "SimpleDebugger", condition: .when(platforms: [.iOS, .macOS, .macCatalyst]))]),
-        .target(name: "SnapshottingTests", dependencies: ["SnapshotPreviewsCore", "SnapshottingTestsObjc"]),
-        .target(name: "SnapshotSharedModels"),
-        // Core functionality
-        .target(name: "SnapshotPreviewsCore", dependencies: ["PreviewsSupport", "SnapshotSharedModels", .product(name: "AccessibilitySnapshotCore", package: "AccessibilitySnapshot", condition: .when(platforms: [.iOS, .macCatalyst]))]),
-        .target(name: "SnapshotPreferences", dependencies: ["SnapshotSharedModels"]),
-        // Inserted dylib
-        .target(name: "Snapshotting", dependencies: ["SnapshottingSwift"]),
-        // Swift code in the inserted dylib
-        .target(name: "SnapshottingSwift", dependencies: ["SnapshotPreviewsCore", .product(name: "FlyingFox", package: "FlyingFox")]),
-        .target(name: "PreviewGallery", dependencies: ["SnapshotPreviewsCore", "SnapshotPreferences"]),
-        .binaryTarget(
-          name: "PreviewsSupport",
-          path: "PreviewsSupport/PreviewsSupport.xcframework"),
-        .testTarget(
-            name: "SnapshotPreviewsTests",
-            dependencies: ["SnapshotPreviewsCore"]),
-    ],
-    cxxLanguageStandard: .cxx11
+  name: "SnapshotPreviews",
+  platforms: [.iOS(.v15), .macOS(.v12), .watchOS(.v9)],
+  products: [
+    // Products define the executables and libraries a package produces, making them visible to other packages.
+    .library(
+      name: "PreviewGallery",
+      type: .static,  // Replace this to build dynamic
+      targets: ["PreviewGallery"]
+    ),
+    // Test library to import in your XCTest target.
+    // This is the only library that depends on XCTest.framework
+    .library(
+      name: "SnapshottingTests",
+      type: .static,  // Replace this to build dynamic
+      targets: ["SnapshottingTests"]
+    ),
+    // Link the main app to this target to use custom snapshot settings
+    // This lib does not get inserted when running tests to avoid
+    // duplicate symbols.
+    .library(
+      name: "SnapshotPreferences",
+      targets: ["SnapshotPreferences"]
+    ),
+    // Core functionality for snapshotting exported from the internal package
+    .library(
+      name: "SnapshotPreviewsCore",
+      targets: ["SnapshotPreviewsCore"]
+    ),
+    // Dynamic library that your main app will have inserted to generate previews
+    .library(
+      name: "Snapshotting",
+      type: .dynamic,
+      targets: ["Snapshotting"]
+    ),
+  ],
+  dependencies: [
+    .package(url: "https://github.com/swhitty/FlyingFox.git", exact: "0.16.0"),
+    .package(
+      url: "https://github.com/EmergeTools/AccessibilitySnapshot.git",
+      exact: "1.0.2"
+    ),
+    .package(
+      url: "https://github.com/EmergeTools/SimpleDebugger.git",
+      exact: "1.0.0"
+    ),
+  ],
+  targets: [
+    // Targets are the basic building blocks of a package, defining a module or a test suite.
+    // Targets can depend on other targets in this package and products from dependencies.
+    // Target that provides the XCTest
+    .target(
+      name: "SnapshottingTestsObjc",
+      dependencies: [
+        .product(
+          name: "SimpleDebugger",
+          package: "SimpleDebugger",
+          condition: .when(platforms: [.iOS, .macOS, .macCatalyst])
+        )
+      ]
+    ),
+    .target(
+      name: "SnapshottingTests",
+      dependencies: ["SnapshotPreviewsCore", "SnapshottingTestsObjc"]
+    ),
+    .target(name: "SnapshotSharedModels"),
+    // Core functionality
+    .target(
+      name: "SnapshotPreviewsCore",
+      dependencies: [
+        "PreviewsSupport", "SnapshotSharedModels",
+        .product(
+          name: "AccessibilitySnapshotCore",
+          package: "AccessibilitySnapshot",
+          condition: .when(platforms: [.iOS, .macCatalyst])
+        ),
+      ]
+    ),
+    .target(
+      name: "SnapshotPreferences",
+      dependencies: ["SnapshotSharedModels"]
+    ),
+    // Inserted dylib
+    .target(name: "Snapshotting", dependencies: ["SnapshottingSwift"]),
+    // Swift code in the inserted dylib
+    .target(
+      name: "SnapshottingSwift",
+      dependencies: [
+        "SnapshotPreviewsCore",
+        .product(name: "FlyingFox", package: "FlyingFox"),
+      ]
+    ),
+    .target(
+      name: "PreviewGallery",
+      dependencies: ["SnapshotPreviewsCore", "SnapshotPreferences"]
+    ),
+    .binaryTarget(
+      name: "PreviewsSupport",
+      path: "PreviewsSupport/PreviewsSupport.xcframework"
+    ),
+    .testTarget(
+      name: "SnapshotPreviewsTests",
+      dependencies: ["SnapshotPreviewsCore", "SnapshotPreferences"]
+    ),
+  ],
+  cxxLanguageStandard: .cxx11
 )

Sources/SnapshotPreviewsCore/EmergeModifierView.swift

@@ -0,0 +1,64 @@
+//
+//  ModifierFinder.swift
+//
+//
+//  Created by Noah Martin on 7/8/24.
+//
+
+import Foundation
+import SnapshotSharedModels
+import SwiftUI
+
+public struct EmergeModifierView: View {
+
+  private static let modifierFinderClass =
+    (NSClassFromString("EmergeModifierFinder") as? NSObject.Type)?.init()
+  private static let finder =
+    modifierFinderClass != nil
+    ? Mirror(reflecting: modifierFinderClass!).descendant("finder")
+      as? (any View) -> any View : nil
+  private static let modifierState =
+    NSClassFromString("EmergeModifierState") as? NSObject.Type
+  private static let stateMirror =
+    modifierState != nil
+    ? Mirror(
+      reflecting: modifierState!
+        .perform(NSSelectorFromString("shared"))
+        .takeUnretainedValue()
+    ) : nil
+
+  private let internalView: AnyView
+
+  init(wrapped: some View) {
+    let rootView = Self.finder?(wrapped)
+    internalView = rootView != nil ? AnyView(rootView!) : AnyView(wrapped)
+  }
+
+  public var body: some View {
+    internalView
+  }
+
+  var emergeRenderingMode: EmergeRenderingMode? {
+    let renderingMode =
+      Self.stateMirror?.descendant("renderingMode")
+      as? EmergeRenderingMode.RawValue
+    return renderingMode != nil
+      ? EmergeRenderingMode(rawValue: renderingMode!) : nil
+  }
+
+  var accessibilityEnabled: Bool? {
+    Self.stateMirror?.descendant("accessibilityEnabled") as? Bool
+  }
+
+  var appStoreSnapshot: Bool? {
+    Self.stateMirror?.descendant("appStoreSnapshot") as? Bool
+  }
+
+  var precision: Float? {
+    Self.stateMirror?.descendant("precision") as? Float
+  }
+
+  var supportsExpansion: Bool {
+    Self.stateMirror?.descendant("expansionPreference") as? Bool ?? true
+  }
+}

Tests/SnapshotPreviewsTests/ConformanceLookupTests.swift

@@ -0,0 +1,17 @@
+import XCTest
+
+@testable import SnapshotPreviewsCore
+
+final class ConformanceLookupTests: XCTestCase {
+  func test_getPreviewTypes() throws {
+    let types = getPreviewTypes()
+    XCTAssertEqual(types.count, 1)
+
+    let firstType = types.first!
+    XCTAssertEqual(
+      "SnapshotPreviewsTests.$s21SnapshotPreviewsTests0019TestViewswift_DJEEdfMX15_0_33_B5E96601318DE1EC85533DD88EB53190Ll7PreviewfMf_15PreviewRegistryfMu_",
+      firstType.name
+    )
+    XCTAssertEqual("PreviewRegistry", firstType.proto)
+  }
+}

Tests/SnapshotPreviewsTests/EmergeModifierStateTests.swift

@@ -0,0 +1,72 @@
+//
+//  EmergeModifierViewTests.swift
+//  SnapshotPreviews
+//
+//  Created by Trevor Elkins on 4/30/25.
+//
+
+import SwiftUI
+import XCTest
+
+@testable import SnapshotPreferences
+@testable import SnapshotSharedModels
+@testable import SnapshotPreviewsCore
+
+final class EmergeModifierStateTests: XCTestCase {
+
+  override func setUp() {
+    super.setUp()
+    EmergeModifierState.shared.reset()
+  }
+
+  func test_storesRenderingMode() {
+    let view = makeBaseText().emergeRenderingMode(.uiView)
+    let state = state(for: view)
+    XCTAssertEqual(state.renderingMode, EmergeRenderingMode.uiView.rawValue)
+  }
+
+  func test_storesPrecision() throws {
+    let view = makeBaseText().emergeSnapshotPrecision(0.95)
+    let state = state(for: view)
+    let precision = try XCTUnwrap(state.precision)
+    XCTAssertEqual(precision, 0.95, accuracy: .ulpOfOne)
+  }
+
+  func test_storesExpansionPreference() {
+    let view = makeBaseText().emergeExpansion(false)
+    let state = state(for: view)
+    XCTAssertEqual(state.expansionPreference, false)
+  }
+
+  func test_storesAccessibilityFlag() {
+    let view = makeBaseText().emergeAccessibility(true)
+    let state = state(for: view)
+    XCTAssertEqual(state.accessibilityEnabled, true)
+  }
+
+  func test_storesAppStoreSnapshotFlag() {
+    let view = makeBaseText().emergeAppStoreSnapshot(true)
+    let state = state(for: view)
+    XCTAssertEqual(state.appStoreSnapshot, true)
+  }
+
+  private func makeBaseText() -> Text { Text("Hello") }
+
+  private func state(
+    for view: some View,
+    file: StaticString = #file,
+    line: UInt = #line
+  ) -> EmergeModifierState {
+    let wrapped = EmergeModifierView(wrapped: view)
+    let hosting = UIHostingController(rootView: wrapped)
+
+    let window = UIWindow(frame: UIScreen.main.bounds)
+    window.rootViewController = hosting
+    window.makeKeyAndVisible()
+
+    // Give SwiftUI one tick to propagate preferences
+    RunLoop.main.run(until: Date(timeIntervalSinceNow: 0.01))
+
+    return EmergeModifierState.shared
+  }
+}