Simplify tests with T.TempDir (#929)

openai_test.go

@@ -31,7 +31,7 @@ func setupAzureTestServer() (client *openai.Client, server *test.ServerTest, tea
 // This function approximates based on the rule of thumb stated by OpenAI:
 // https://beta.openai.com/tokenizer
 //
-// TODO: implement an actual tokenizer for GPT-3 and Codex (once available)
+// TODO: implement an actual tokenizer for GPT-3 and Codex (once available).
 func numTokens(s string) int {
 	return int(float32(len(s)) / 4)
 }