Add unit tests

Author: andrewheard

FirebaseVertexAI/Sources/ModalityTokenCount.swift

@@ -68,7 +68,7 @@ extension ModalityTokenCount: Decodable {
 
   public init(from decoder: any Decoder) throws {
     let container = try decoder.container(keyedBy: CodingKeys.self)
-    self.modality = try container.decode(ContentModality.self, forKey: .modality)
-    self.tokenCount = try container.decodeIfPresent(Int.self, forKey: .tokenCount) ?? 0
+    modality = try container.decode(ContentModality.self, forKey: .modality)
+    tokenCount = try container.decodeIfPresent(Int.self, forKey: .tokenCount) ?? 0
   }
 }

FirebaseVertexAI/Tests/Unit/Types/ModalityTokenCountTests.swift

@@ -0,0 +1,88 @@
+// Copyright 2025 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 FirebaseVertexAI
+import XCTest
+
+@available(iOS 15.0, macOS 12.0, macCatalyst 15.0, tvOS 15.0, watchOS 8.0, *)
+final class ModalityTokenCountTests: XCTestCase {
+  let decoder = JSONDecoder()
+
+  // MARK: - Decoding Tests
+
+  func testDecodeModalityTokenCount_valid() throws {
+    let json = """
+    {
+      "modality": "TEXT",
+      "tokenCount": 123
+    }
+    """
+    let jsonData = try XCTUnwrap(json.data(using: .utf8))
+
+    let tokenCount = try decoder.decode(ModalityTokenCount.self, from: jsonData)
+
+    XCTAssertEqual(tokenCount.modality, .text)
+    XCTAssertEqual(tokenCount.modality.rawValue, "TEXT")
+    XCTAssertEqual(tokenCount.tokenCount, 123)
+  }
+
+  func testDecodeModalityTokenCount_missingTokenCount_defaultsToZero() throws {
+    let json = """
+    {
+      "modality": "AUDIO"
+    }
+    """
+    let jsonData = try XCTUnwrap(json.data(using: .utf8))
+
+    let tokenCount = try decoder.decode(ModalityTokenCount.self, from: jsonData)
+
+    XCTAssertEqual(tokenCount.modality, .audio)
+    XCTAssertEqual(tokenCount.modality.rawValue, "AUDIO")
+    XCTAssertEqual(tokenCount.tokenCount, 0)
+  }
+
+  func testDecodeModalityTokenCount_unrecognizedModalityString_succeeds() throws {
+    let newModality = "NEW_MODALITY_NAME"
+    let json = """
+    {
+      "modality": "\(newModality)",
+      "tokenCount": 50
+    }
+    """
+    let jsonData = try XCTUnwrap(json.data(using: .utf8))
+
+    let tokenCount = try decoder.decode(ModalityTokenCount.self, from: jsonData)
+
+    XCTAssertEqual(tokenCount.tokenCount, 50)
+    XCTAssertEqual(tokenCount.modality.rawValue, newModality)
+  }
+
+  func testDecodeModalityTokenCount_missingModalityKey_throws() throws {
+    let json = """
+    {
+      "tokenCount": 50
+    }
+    """
+    let jsonData = try XCTUnwrap(json.data(using: .utf8))
+
+    do {
+      _ = try decoder.decode(ModalityTokenCount.self, from: jsonData)
+      XCTFail("Expected a DecodingError, but decoding succeeded.")
+    } catch let DecodingError.keyNotFound(key, _) {
+      XCTAssertEqual(key.stringValue, "modality")
+    } catch {
+      XCTFail("Expected a DecodingError.keyNotFound, but received \(error)")
+    }
+  }
+}