Modify the test module, add the file upload test, and add the image edit api (#63)

* Modify the test module, add the file upload test, and add the image editing api

* fix golangci-lint

* fix golangci-lint

* Static file deletion, file directory name modification

* fix

* test-server-related logic encapsulated in a single tidy
 struct

---------

Co-authored-by: julian_huang <julian.huang@yuansuan.com>

files.go

@@ -9,7 +9,6 @@ import (
 	"net/http"
 	"net/url"
 	"os"
-	"strings"
 )
 
 type FileRequest struct {
@@ -56,13 +55,9 @@ func (c *Client) CreateFile(ctx context.Context, request FileRequest) (file File
 	var b bytes.Buffer
 	w := multipart.NewWriter(&b)
 
-	var fw, pw io.Writer
-	pw, err = w.CreateFormField("purpose")
-	if err != nil {
-		return
-	}
+	var fw io.Writer
 
-	_, err = io.Copy(pw, strings.NewReader(request.Purpose))
+	err = w.WriteField("purpose", request.Purpose)
 	if err != nil {
 		return
 	}