go - 测试 Go http.Request.FormFile？

Question

尝试测试端点时如何设置 Request.FormFile？

部分代码:

func (a *EP) Endpoint(w http.ResponseWriter, r *http.Request) {
    ...

    x, err := strconv.Atoi(r.FormValue("x"))
    if err != nil {
        a.ren.Text(w, http.StatusInternalServerError, err.Error())
        return
    }

    f, fh, err := r.FormFile("y")
    if err != nil {
        a.ren.Text(w, http.StatusInternalServerError, err.Error())
        return
    }
    defer f.Close()
    ...
}

我如何使用 httptest 库生成具有我可以在 FormFile 中获取的值的发布请求？

Answer 1

您不需要按照其他答案的建议模拟完整的 FormFile 结构。 mime/multipart 包实现了一个允许您创建 FormFile 的 Writer 类型。来自 the docs

CreateFormFile is a convenience wrapper around CreatePart. It createsa new form-data header with the provided field name and file name.

func (w *Writer) CreateFormFile(fieldname, filename string) (io.Writer, error)

然后，您可以将此 io.Writer 传递给 httptest.NewRequest，它接受一个 reader 作为参数。

request := httptest.NewRequest("POST", "/", myReader)

为此，您可以将 FormFile 写入 io.ReaderWriter 缓冲区或使用 io.Pipe。这是一个使用管道的完整示例:

func TestUploadImage(t *testing.T) {
    // Set up a pipe to avoid buffering
    pr, pw := io.Pipe()
    // This writer is going to transform 
    // what we pass to it to multipart form data
    // and write it to our io.Pipe
    writer := multipart.NewWriter(pw)

    go func() {
        defer writer.Close()
        // We create the form data field 'fileupload'
        // which returns another writer to write the actual file 
        part, err := writer.CreateFormFile("fileupload", "someimg.png")
        if err != nil {
            t.Error(err)
        }

        // https://yourbasic.org/golang/create-image/
        img := createImage()

        // Encode() takes an io.Writer.
        // We pass the multipart field
        // 'fileupload' that we defined
        // earlier which, in turn, writes
        // to our io.Pipe
        err = png.Encode(part, img)
        if err != nil {
            t.Error(err)
        }
    }()

    // We read from the pipe which receives data
    // from the multipart writer, which, in turn,
    // receives data from png.Encode().
    // We have 3 chained writers!
    request := httptest.NewRequest("POST", "/", pr)
    request.Header.Add("Content-Type", writer.FormDataContentType())

    response := httptest.NewRecorder()
    handler := UploadFileHandler()
    handler.ServeHTTP(response, request)

    t.Log("It should respond with an HTTP status code of 200")
    if response.Code != 200 {
        t.Errorf("Expected %s, received %d", 200, response.Code)
    }
    t.Log("It should create a file named 'someimg.png' in uploads folder")
    if _, err := os.Stat("./uploads/someimg.png"); os.IsNotExist(err) {
        t.Error("Expected file ./uploads/someimg.png' to exist")
    }
}

此函数利用 image 包动态生成文件，利用您可以将 io.Writer 传递给 png.Encode 。同样，您可以传递您的多部分 Writer 以生成 CSV 格式的字节(NewWriter 在包“encoding/csv”中)，动态生成一个文件，而无需从您的文件系统中读取任何内容。