feat: add tests

Author: mackoj

Package.swift

@@ -32,6 +32,7 @@ let package = Package(
       name: "SnapshotTesting",
       dependencies: ["SnapshotTestingPlugin"]
     ),
+    .target(name: "SnapshotTestingPlugin"),
     .target(
       name: "InlineSnapshotTesting",
       dependencies: [

Sources/SnapshotTesting/Documentation.docc/Articles/Plugins.md

@@ -17,11 +17,3 @@ The primary components of the plugin system include:
 - **Objective-C Runtime Integration**: Allows automatic discovery of plugins that conform to specific protocols.
 
 The `PluginRegistry` is a singleton that registers plugins during its initialization. Plugins can be retrieved by their identifier or cast to specific types, allowing flexible interaction.
-
-## ImageSerializer
-
-The `ImageSerializer` is a plugin-based system that provides support for encoding and decoding images. It leverages the plugin architecture to extend its support for different image formats without needing to modify the core system.
-
-Plugins that conform to the `ImageSerializationPlugin` protocol can be registered into the `PluginRegistry` and used to encode or decode images in different formats, such as PNG, JPEG, WebP, HEIC, and more.
-
-When a plugin supporting a specific image format is available, the `ImageSerializer` can dynamically choose the correct plugin based on the image format required, ensuring modularity and scalability in image handling.

Sources/SnapshotTesting/Plugins/PluginRegistry.swift

@@ -1,7 +1,6 @@
 #if canImport(SwiftUI) && canImport(ObjectiveC)
 import Foundation
 import ObjectiveC.runtime
-import ImageSerializationPlugin
 import SnapshotTestingPlugin
 
 /// A singleton class responsible for managing and registering plugins conforming to the `SnapshotTestingPlugin` protocol.
@@ -95,5 +94,16 @@ public class PluginRegistry {
       self.registerPlugin(pluginType.init())
     }
   }
+  
+  // TEST-ONLY Reset Method
+  #if DEBUG
+  internal static func reset() {
+      shared.plugins.removeAll()
+  }
+
+  internal static func automaticPluginRegistration() {
+      shared.automaticPluginRegistration()
+  }
+  #endif
 }
 #endif

Tests/SnapshotTestingTests/PluginRegistryTests.swift

@@ -0,0 +1,73 @@
+#if canImport(SwiftUI) && canImport(ObjectiveC)
+import XCTest
+import ObjectiveC
+@testable import SnapshotTesting
+import SnapshotTestingPlugin
+
+class MockPlugin: NSObject, SnapshotTestingPlugin {
+  static var identifier: String = "MockPlugin"
+  
+  required override init() {
+    super.init()
+  }
+}
+
+class AnotherMockPlugin: NSObject, SnapshotTestingPlugin {
+  static var identifier: String = "AnotherMockPlugin"
+  
+  required override init() {
+    super.init()
+  }
+}
+
+final class PluginRegistryTests: XCTestCase {
+  
+  override func setUp() {
+    super.setUp()
+    PluginRegistry.reset() // Reset state before each test
+  }
+  
+  override func tearDown() {
+    PluginRegistry.reset() // Reset state after each test
+    super.tearDown()
+  }
+  
+  func testRegisterPlugin() {
+    // Register a mock plugin
+    PluginRegistry.registerPlugin(MockPlugin())
+    
+    // Retrieve the plugin by identifier
+    let retrievedPlugin: MockPlugin? = PluginRegistry.plugin(for: MockPlugin.identifier)
+    XCTAssertNotNil(retrievedPlugin)
+  }
+  
+  func testRetrieveNonExistentPlugin() {
+    // Try to retrieve a non-existent plugin
+    let nonExistentPlugin: MockPlugin? = PluginRegistry.plugin(for: "NonExistentPlugin")
+    XCTAssertNil(nonExistentPlugin)
+  }
+  
+  func testAllPlugins() {
+    // Register two mock plugins
+    PluginRegistry.registerPlugin(MockPlugin())
+    PluginRegistry.registerPlugin(AnotherMockPlugin())
+    
+    // Retrieve all plugins
+    let allPlugins: [SnapshotTestingPlugin] = PluginRegistry.allPlugins()
+    
+    XCTAssertEqual(allPlugins.count, 2)
+    XCTAssertTrue(allPlugins.contains { $0 is MockPlugin })
+    XCTAssertTrue(allPlugins.contains { $0 is AnotherMockPlugin })
+  }
+  
+  func testAutomaticPluginRegistration() {
+    // Automatically register plugins using the Objective-C runtime
+    PluginRegistry.automaticPluginRegistration() // Reset state before each test
+    
+    // Verify if the mock plugin was automatically registered
+    let registeredPlugin: MockPlugin? = PluginRegistry.plugin(for: MockPlugin.identifier)
+    XCTAssertNotNil(registeredPlugin)
+  }
+}
+
+#endif