How to write unit test case using golang echo, when we have multipart form files and json request?

[SajaiPrathap070]

In the request handler we are reading form value using c.FormValue and multipart files using c.MultipartForm.

but I am not sure how to write the unit test case for handling multipart files.

For more details pls look into the below code:

Handler code:

func (h *testimonialHandlers) UpdateTestimonial(c echo.Context) error {

	jsonValue := c.FormValue("json")
	if len(jsonValue) == 0 {

		log.Errorf("Error: %#v - Input: %#v\n", jsonValue, nil)
		return errorResponse(c, http.StatusBadRequest, "json is empty")
	}

	var testimonialModel business.Testimonial
	if err := json.Unmarshal([]byte(jsonValue), &testimonialModel); err != nil {

		log.Errorf("Error: %#v - Input: %#v\n", err, jsonValue)
		return errorResponse(c, http.StatusBadRequest, "error while unmarshalling the json")
	}

	if err := c.Validate(&testimonialModel); err != nil {

		log.Errorf("Error: %#v - Input: %#v\n", err, testimonialModel)
		return errorResponse(c, http.StatusBadRequest, "Required field is empty!")
	}

	var files []*multipart.FileHeader = nil
	if testimonialModel.Type == business.IMAGE || testimonialModel.Type == business.VIDEO {

		form, err := c.MultipartForm()
		if err != nil {

			log.Errorf("Error: %#v - Input: %#v\n", err, form)
			return errorResponse(c, http.StatusBadRequest, "error while reading multi-part form")
		}

		files = form.File["file"]
	}

	if updateResult, err := h.service.UpdateTestimonial(testimonialModel, files); err == nil && len(updateResult) > 1 {

		var status = transport.Status{Code: http.StatusOK, Msg: "Successful"}
		var data = transport.CreateData{Flag: true, Message: "Created", Id: updateResult}
		return c.JSON(status.Code, transport.CreateResponse{Status: status, Data: data})
	} else {

		log.Errorf("Error: %#v - Input: %#v\n", err, testimonialModel)
		return errorResponse(c, http.StatusInternalServerError, "Failed to update or create!")
	}
}

Unit test case code:

func TestTestimonialsHandlers_UpdateTestimonial(t *testing.T) {

	var testCases = []struct {
		name        string
		whenPayload string
		dBWhen      business.Testimonial
		dBReturn    int64
		dBError     error
		expect      string
		expectError string
	}{
		{ // create testimonial
			name:        "ok, happy case",
			whenPayload: `{"type":1, "uid": "000000000000000000000000","apv":true, "rank":1, "ttl": "Lost 5kg in 3 months. from 100kg to 95kg", "text": "I plan to use this for a long time!", "mda": [{"name": "Banner3.png", "ttl": "before image", "url": "/62fcd8c098eb9d5ed0380000/testimonial/Banner3.png"},{"name": "Banner4.png", "ttl": "after image", "url": "/62fcd8c098eb9d5ed0380000/testimonial/Banner4.png"}], "user": {"name": "christina", "org": "EkoHunt", "role": "CTO", "url": "/profile/Avatar6.png"}}`, // ID could be sent
			dBWhen:      business.Testimonial{Type: 1, UserId: "000000000000000000000000", Approve: true, Rank: 1, Title: "Lost 5kg in 3 months. from 100kg to 95kg", Text: "I plan to use this for a long time!", Media: []business.Media{{Name: "Banner3.png", Title: "before image", URL: "/62fcd8c098eb9d5ed0380000/testimonial/Banner3.png"}, {Name: "Banner4.png", Title: "after image", URL: "/62fcd8c098eb9d5ed0380000/testimonial/Banner4.png"}}, User: business.User{Name: "christina", Org: "EkoHunt", Role: "CTO", URL: "/profile/Avatar6.png"}},
			dBReturn:    999,
			expect:      `{"status": {"code": 200, "msg": "Successful"}, "data": {"flag": true, "msg": "Created", "id": "63495993a422ac8329667e86"}}`,
		},
	}
	for _, tc := range testCases {

		t.Run(tc.name, func(t *testing.T) {

			database := new(dbTestimonialsMock)
			database.On("UpdateTestimonial", tc.dBWhen).Return(tc.dBReturn, tc.dBError)

			req := httptest.NewRequest(http.MethodPut, fmt.Sprintf("/put/?json=%s", tc.whenPayload), nil)
			req.Header.Set(echo.HeaderContentType, echo.MIMEApplicationJSON)
			rec := httptest.NewRecorder()
			e := echo.New()
			c := e.NewContext(req, rec)
			e.Validator = &CustomValidator{Validator: validator.New()} //for custom validator
			h := testimonialHandlers{service: database}
			err := h.UpdateTestimonial(c)

			assert.JSONEq(t, tc.expect, string(rec.Body.Bytes()))
			if tc.expectError != "" {
				assert.EqualError(t, err, tc.expectError)
			} else {
				assert.NoError(t, err)
			}
		})
	}
}

[aldas]

Try something like this

func TestMultiPartForm(t *testing.T) {
	e := echo.New()

	bodyBuffer := new(bytes.Buffer)
	mw := multipart.NewWriter(bodyBuffer) // see https://pkg.go.dev/mime/multipart
	mw.WriteField("id", "1")
	mw.WriteField("json", `{"ok":true}`)
	mw.Close()

	req := httptest.NewRequest(http.MethodPost, "/", bodyBuffer)
	rec := httptest.NewRecorder()
	req.Header.Set(echo.HeaderContentType, mw.FormDataContentType())

	c := e.NewContext(req, rec)

	type payload = struct {
		ID   int    `form:"id"`
		JSON string `form:"json"`
	}
	u := new(payload)

	err := c.Bind(u)
	if assert.NoError(t, err) {
		assert.Equal(t, 1, u.ID)
		assert.Equal(t, `{"ok":true}`, u.JSON)
	}
}

and if you need to add file to that multipartform

	part, err := mw.CreateFormFile("file", "myfile.txt")
	if err != nil {
		t.Fatal(err)
	}
	file := strings.NewReader(`contents of my file`)
	io.Copy(part, file)