refactor: refactoring http request creation and sending (#395)

* refactoring http request creation and sending

* fix lint error

* increase the test coverage of client.go

* refactor: Change the style of HTTPRequestBuilder.Build func to one-argument-per-line.

stream_test.go

@@ -6,7 +6,9 @@ import (
 	"errors"
 	"io"
 	"net/http"
+	"os"
 	"testing"
+	"time"
 
 	. "github.com/sashabaranov/go-openai"
 	"github.com/sashabaranov/go-openai/internal/test/checks"
@@ -300,6 +302,30 @@ func TestCreateCompletionStreamBrokenJSONError(t *testing.T) {
 	}
 }
 
+func TestCreateCompletionStreamReturnTimeoutError(t *testing.T) {
+	client, server, teardown := setupOpenAITestServer()
+	defer teardown()
+	server.RegisterHandler("/v1/completions", func(w http.ResponseWriter, r *http.Request) {
+		time.Sleep(10 * time.Nanosecond)
+	})
+	ctx := context.Background()
+	ctx, cancel := context.WithTimeout(ctx, time.Nanosecond)
+	defer cancel()
+
+	_, err := client.CreateCompletionStream(ctx, CompletionRequest{
+		Prompt:    "Ex falso quodlibet",
+		Model:     "text-davinci-002",
+		MaxTokens: 10,
+		Stream:    true,
+	})
+	if err == nil {
+		t.Fatal("Did not return error")
+	}
+	if !os.IsTimeout(err) {
+		t.Fatal("Did not return timeout error")
+	}
+}
+
 // Helper funcs.
 func compareResponses(r1, r2 CompletionResponse) bool {
 	if r1.ID != r2.ID || r1.Object != r2.Object || r1.Created != r2.Created || r1.Model != r2.Model {