Add code snippets for text generation

Package.swift

@@ -44,5 +44,10 @@ let package = Package(
         .process("GoogleAITests/GenerateContentResponses"),
       ]
     ),
+    .testTarget(
+      name: "CodeSnippetTests",
+      dependencies: ["GoogleGenerativeAI"],
+      path: "samples"
+    ),
   ]
 )

samples/APIKey.swift

@@ -0,0 +1,62 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import Foundation
+import XCTest
+
+/// A private wrapper for `APIKey`, hiding it from test files.
+private enum APIKeyCodeSnippet {
+  // The implementation of `APIKey` for use in documentation code snippets; shown in
+  // https://ai.google.dev/gemini-api/docs/quickstart?lang=swift
+  // [START setup_api_key]
+  enum APIKey {
+    // Fetch the API key from `GenerativeAI-Info.plist`
+    static var `default`: String {
+      guard let filePath = Bundle.main.path(forResource: "GenerativeAI-Info", ofType: "plist")
+      else {
+        fatalError("Couldn't find file 'GenerativeAI-Info.plist'.")
+      }
+      let plist = NSDictionary(contentsOfFile: filePath)
+      guard let value = plist?.object(forKey: "API_KEY") as? String else {
+        fatalError("Couldn't find key 'API_KEY' in 'GenerativeAI-Info.plist'.")
+      }
+      if value.starts(with: "_") {
+        fatalError(
+          "Follow the instructions at https://ai.google.dev/tutorials/setup to get an API key."
+        )
+      }
+      return value
+    }
+  }
+  // [END setup_api_key]
+}
+
+/// Protocol to ensure that the `APIKey` APIs do not diverge.
+protocol APIKeyProtocol {
+  static var `default`: String { get }
+}
+
+extension APIKeyCodeSnippet.APIKey: APIKeyProtocol {}
+
+/// An implementation of `APIKey` for use in code snippet tests only.
+enum APIKey: APIKeyProtocol {
+  static let apiKeyEnvVar = "API_KEY"
+
+  static var `default`: String {
+    guard let apiKey = ProcessInfo.processInfo.environment[apiKeyEnvVar] else {
+      return ""
+    }
+    return apiKey
+  }
+}

samples/TextGeneration.swift

@@ -0,0 +1,166 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import GoogleGenerativeAI
+import XCTest
+
+// Set up your API Key
+// ====================
+// To use the Gemini API, you'll need an API key. To learn more, see the "Set up your API Key"
+// section in the Gemini API quickstart:
+// https://ai.google.dev/gemini-api/docs/quickstart?lang=swift#set-up-api-key
+
+#if canImport(UIKit)
+  @available(iOS 15.0, macCatalyst 15.0, *)
+  final class TextGeneration: XCTestCase {
+    override func setUpWithError() throws {
+      try XCTSkipIf(
+        APIKey.default.isEmpty,
+        "`\(APIKey.apiKeyEnvVar)` environment variable not set."
+      )
+    }
+
+    func testTextOnlyPrompt() async throws {
+      // [START text_gen_text_only_prompt]
+      let generativeModel =
+        GenerativeModel(
+          // Specify a Gemini model appropriate for your use case
+          name: "gemini-1.5-flash",
+          // Access your API key from your on-demand resource .plist file (see "Set up your API key"
+          // above)
+          apiKey: APIKey.default
+        )
+
+      let prompt = "Write a story about a magic backpack."
+      let response = try await generativeModel.generateContent(prompt)
+      if let text = response.text {
+        print(text)
+      }
+      // [END text_gen_text_only_prompt]
+    }
+
+    func testTextOnlyPromptStreaming() async throws {
+      // [START text_gen_text_only_prompt_streaming]
+      let generativeModel =
+        GenerativeModel(
+          // Specify a Gemini model appropriate for your use case
+          name: "gemini-1.5-flash",
+          // Access your API key from your on-demand resource .plist file (see "Set up your API key"
+          // above)
+          apiKey: APIKey.default
+        )
+
+      let prompt = "Write a story about a magic backpack."
+      // Use streaming with text-only input
+      for try await response in generativeModel.generateContentStream(prompt) {
+        if let text = response.text {
+          print(text)
+        }
+      }
+      // [END text_gen_text_only_prompt_streaming]
+    }
+
+    func testMultimodalOneImagePrompt() async throws {
+      // [START text_gen_multimodal_one_image_prompt]
+      let generativeModel =
+        GenerativeModel(
+          // Specify a Gemini model appropriate for your use case
+          name: "gemini-1.5-flash",
+          // Access your API key from your on-demand resource .plist file (see "Set up your API key"
+          // above)
+          apiKey: APIKey.default
+        )
+
+      guard let image = UIImage(systemName: "cloud.sun") else { fatalError() }
+
+      let prompt = "What's in this picture?"
+
+      let response = try await generativeModel.generateContent(image, prompt)
+      if let text = response.text {
+        print(text)
+      }
+      // [END text_gen_multimodal_one_image_prompt]
+    }
+
+    func testMultimodalOneImagePromptStreaming() async throws {
+      // [START text_gen_multimodal_one_image_prompt_streaming]
+      let generativeModel =
+        GenerativeModel(
+          // Specify a Gemini model appropriate for your use case
+          name: "gemini-1.5-flash",
+          // Access your API key from your on-demand resource .plist file (see "Set up your API key"
+          // above)
+          apiKey: APIKey.default
+        )
+
+      guard let image = UIImage(systemName: "cloud.sun") else { fatalError() }
+
+      let prompt = "What's in this picture?"
+
+      for try await response in generativeModel.generateContentStream(image, prompt) {
+        if let text = response.text {
+          print(text)
+        }
+      }
+      // [END text_gen_multimodal_one_image_prompt_streaming]
+    }
+
+    func testMultimodalMultiImagePrompt() async throws {
+      // [START text_gen_multimodal_multi_image_prompt]
+      let generativeModel =
+        GenerativeModel(
+          // Specify a Gemini model appropriate for your use case
+          name: "gemini-1.5-flash",
+          // Access your API key from your on-demand resource .plist file (see "Set up your API key"
+          // above)
+          apiKey: APIKey.default
+        )
+
+      guard let image1 = UIImage(systemName: "cloud.sun") else { fatalError() }
+      guard let image2 = UIImage(systemName: "cloud.heavyrain") else { fatalError() }
+
+      let prompt = "What's the difference between these pictures?"
+
+      let response = try await generativeModel.generateContent(image1, image2, prompt)
+      if let text = response.text {
+        print(text)
+      }
+      // [END text_gen_multimodal_multi_image_prompt]
+    }
+
+    func testMultimodalMultiImagePromptStreaming() async throws {
+      // [START text_gen_multimodal_multi_image_prompt_streaming]
+      let generativeModel =
+        GenerativeModel(
+          // Specify a Gemini model appropriate for your use case
+          name: "gemini-1.5-flash",
+          // Access your API key from your on-demand resource .plist file (see "Set up your API key"
+          // above)
+          apiKey: APIKey.default
+        )
+
+      guard let image1 = UIImage(systemName: "cloud.sun") else { fatalError() }
+      guard let image2 = UIImage(systemName: "cloud.heavyrain") else { fatalError() }
+
+      let prompt = "What's the difference between these pictures?"
+
+      for try await response in generativeModel.generateContentStream(image1, image2, prompt) {
+        if let text = response.text {
+          print(text)
+        }
+      }
+      // [END text_gen_multimodal_multi_image_prompt_streaming]
+    }
+  }
+#endif // canImport(UIKit)