[Vertex AI] Add compilation tests for GCS snippets (#14164)

Author: andrewheard

FirebaseVertexAI/Tests/Unit/Snippets/CloudStorageSnippets.swift

@@ -0,0 +1,67 @@
+// 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.
+
+#if SWIFT_PACKAGE // The FirebaseStorage dependency has only been added in Package.swift.
+
+  import FirebaseCore
+  import FirebaseStorage
+  import FirebaseVertexAI
+
+  // These CloudStorageSnippets are not currently runnable due to the GCS upload paths but are used
+  // as compilation tests.
+  @available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
+  final class CloudStorageSnippets {
+    let model: GenerativeModel! = nil
+
+    func cloudStorageFile_referenceMIMEType() async throws {
+      // Upload an image file using Cloud Storage for Firebase.
+      let storageRef = Storage.storage().reference(withPath: "images/image.jpg")
+      guard let imageURL = Bundle.main.url(forResource: "image", withExtension: "jpg") else {
+        fatalError("File 'image.jpg' not found in main bundle.")
+      }
+      let metadata = try await storageRef.putFileAsync(from: imageURL)
+
+      // Get the MIME type and Cloud Storage for Firebase URL.
+      guard let mimeType = metadata.contentType else {
+        fatalError("The MIME type of the uploaded image is nil.")
+      }
+      // Construct a URL in the required format.
+      let storageURL = "gs://\(storageRef.bucket)/\(storageRef.fullPath)"
+
+      let prompt = "What's in this picture?"
+      // Construct the imagePart with the MIME type and the URL.
+      let imagePart = FileDataPart(uri: storageURL, mimeType: mimeType)
+
+      // To generate text output, call generateContent with the prompt and the imagePart.
+      let result = try await model.generateContent(prompt, imagePart)
+      if let text = result.text {
+        print(text)
+      }
+    }
+
+    func cloudStorageFile_explicitMIMEType() async throws {
+      let prompt = "What's in this picture?"
+      // Construct an imagePart that explicitly includes the MIME type and
+      // Cloud Storage for Firebase URL values.
+      let imagePart = FileDataPart(uri: "gs://bucket-name/path/image.jpg", mimeType: "image/jpeg")
+
+      // To generate text output, call generateContent with the prompt and imagePart.
+      let result = try await model.generateContent(prompt, imagePart)
+      if let text = result.text {
+        print(text)
+      }
+    }
+  }
+
+#endif // SWIFT_PACKAGE

Package.swift

@@ -1310,7 +1310,10 @@ let package = Package(
     ),
     .testTarget(
       name: "FirebaseVertexAIUnit",
-      dependencies: ["FirebaseVertexAI"],
+      dependencies: [
+        "FirebaseVertexAI",
+        "FirebaseStorage",
+      ],
       path: "FirebaseVertexAI/Tests/Unit",
       resources: [
         .process("vertexai-sdk-test-data/mock-responses"),