Make "Content" field in "ChatCompletionMessage" omitempty (#926)

chat.go

@@ -93,7 +93,7 @@ type ChatMessagePart struct {
 
 type ChatCompletionMessage struct {
 	Role         string `json:"role"`
-	Content      string `json:"content"`
+	Content      string `json:"content,omitempty"`
 	Refusal      string `json:"refusal,omitempty"`
 	MultiContent []ChatMessagePart
 
@@ -132,7 +132,7 @@ func (m ChatCompletionMessage) MarshalJSON() ([]byte, error) {
 
 	msg := struct {
 		Role         string            `json:"role"`
-		Content      string            `json:"content"`
+		Content      string            `json:"content,omitempty"`
 		Refusal      string            `json:"refusal,omitempty"`
 		MultiContent []ChatMessagePart `json:"-"`
 		Name         string            `json:"name,omitempty"`
@@ -146,7 +146,7 @@ func (m ChatCompletionMessage) MarshalJSON() ([]byte, error) {
 func (m *ChatCompletionMessage) UnmarshalJSON(bs []byte) error {
 	msg := struct {
 		Role         string `json:"role"`
-		Content      string `json:"content"`
+		Content      string `json:"content,omitempty"`
 		Refusal      string `json:"refusal,omitempty"`
 		MultiContent []ChatMessagePart
 		Name         string        `json:"name,omitempty"`

chat_test.go

@@ -631,7 +631,7 @@ func TestMultipartChatMessageSerialization(t *testing.T) {
 		t.Fatalf("Unexpected error")
 	}
 	res = strings.ReplaceAll(string(s), " ", "")
-	if res != `{"role":"user","content":""}` {
+	if res != `{"role":"user"}` {
 		t.Fatalf("invalid message: %s", string(s))
 	}
 }

openai_test.go

@@ -29,7 +29,7 @@ func setupAzureTestServer() (client *openai.Client, server *test.ServerTest, tea
 
 // numTokens Returns the number of GPT-3 encoded tokens in the given text.
 // This function approximates based on the rule of thumb stated by OpenAI:
-// https://beta.openai.com/tokenizer
+// https://beta.openai.com/tokenizer/
 //
 // TODO: implement an actual tokenizer for GPT-3 and Codex (once available).
 func numTokens(s string) int {