Annotate @mainactor for tests using shared instance of tokenizer

Author: mattt

Tests/TokenizersTests/BertTokenizerTests.swift

@@ -83,6 +83,7 @@ private enum Squad {
 
 // MARK: -
 
+@MainActor
 private let bertTokenizer: BertTokenizer = {
     let vocab = {
         let url = Bundle.module.url(forResource: "bert-vocab", withExtension: "txt")!
@@ -101,6 +102,7 @@ private let bertTokenizer: BertTokenizer = {
 // MARK: -
 
 @Suite("BERT Tokenizer Tests")
+@MainActor
 struct BertTokenizerTests {
     @Test("Basic tokenizer correctly tokenizes text")
     func testBasicTokenizer() {

Tests/TokenizersTests/ChatTemplateTests.swift

@@ -19,6 +19,7 @@ struct ChatTemplateTests {
         ]
     ]
 
+    @MainActor
     static let phiTokenizerTask = Task {
         try await AutoTokenizer.from(pretrained: "microsoft/Phi-3-mini-128k-instruct")
     }
@@ -27,6 +28,7 @@ struct ChatTemplateTests {
         try await phiTokenizerTask.value
     }
 
+    @MainActor
     static let tokenizerWithTemplateArrayTask = Task {
         try await AutoTokenizer.from(pretrained: "mlx-community/Mistral-7B-Instruct-v0.3-4bit")
     }