I writing a client that connects to a server with REST endpoints. The client needs to make a chain of 11 different requests to complete an action (it's a rococo backup system).
I'm writing my client in Go and I also want to write my mocks/tests in Go. What I'm unclear about is how a test called func TestMain would call into the client's func main(), to test completion of the chain of 11 requests.
My client's binary would be run from the shell in the following way:
$ client_id=12345 region=apac3 backup
How would I call func main() from the tests, with environment variables set? Or is there another approach? (I'm comfortable writing tests, so that's not the issue)
I'm looking at the Advanced Example in jarcoal/httpmock (but I could use another library). At the end the example says // do stuff that adds and checks articles, is that where I would call main()?
I've pasted the Advanced Example below, for future reference.
func TestFetchArticles(t *testing.T) {
httpmock.Activate()
defer httpmock.DeactivateAndReset()
// our database of articles
articles := make([]map[string]interface{}, 0)
// mock to list out the articles
httpmock.RegisterResponder("GET", "https://api.mybiz.com/articles.json",
func(req *http.Request) (*http.Response, error) {
resp, err := httpmock.NewJsonResponse(200, articles)
if err != nil {
return httpmock.NewStringResponse(500, ""), nil
}
return resp, nil
},
)
// mock to add a new article
httpmock.RegisterResponder("POST", "https://api.mybiz.com/articles.json",
func(req *http.Request) (*http.Response, error) {
article := make(map[string]interface{})
if err := json.NewDecoder(req.Body).Decode(&article); err != nil {
return httpmock.NewStringResponse(400, ""), nil
}
articles = append(articles, article)
resp, err := httpmock.NewJsonResponse(200, article)
if err != nil {
return httpmock.NewStringResponse(500, ""), nil
}
return resp, nil
},
)
// do stuff that adds and checks articles
}
Writing this out helped me answer my own question.
main() would read in environment variables and then call a function like doBackup(client_id, region). My test would mock the endpoints and then call doBackup(client_id, region).
Related
I'm new in Go and unit test. I build a samll side projecy called "urlshortener" using Go with Gorm, mux and postgresql.
There is a qeustion annoying me after search many articles.
To make the question clean, I delete some irrelevant code like connect db, .env, etc
My code is below(main.go):
package main
type Url struct {
ID uint `gorm:"primaryKey"` // used for shortUrl index
Url string `gorm:"unique"` // prevent duplicate url
ExpireAt string
ShortUrl string
}
var db *gorm.DB
var err error
func main() {
// gain access to database by getting .env
...
// database connection string
...
// make migrations to the dbif they have not already been created
db.AutoMigrate(&Url{})
// API routes
router := mux.NewRouter()
router.HandleFunc("/{id}", getURL).Methods("GET")
router.HandleFunc("/api/v1/urls", createURL).Methods("POST")
router.HandleFunc("/create/urls", createURLs).Methods("POST")
// Listener
http.ListenAndServe(":80", router)
// close connection to db when main func finishes
defer db.Close()
}
Now I'm building unit test for getURL function, which is a GET method to get data from my postgresql database called urlshortener and the table name is urls.
Here is getURL function code:
func getURL(w http.ResponseWriter, r *http.Request) {
params := mux.Vars(r)
var url Url
err := db.Find(&url, params["id"]).Error
if err != nil {
w.WriteHeader(http.StatusNotFound)
} else {
w.WriteHeader(http.StatusOK)
json.NewEncoder(w).Encode(url.Url)
}
}
This is work fine with my database. See curl command below:
I know that the unit test is not for mock data, and it aim to test a function/method is stable or not. Although I import mux and net/http for conncetion, but I think the unit test on it should be "SQL syntax". So I decide to focus on testing if gorm return the right value to the test function.
In this case, db.Find will return a *gorm.DB struct which should be exactly same with second line. (see docs https://gorm.io/docs/query.html)
db.Find(&url, params["id"])
SELECT * FROM urls WHICH id=<input_number>
My question is how to write a unit test on it for check the SQL syntax is correct or not in this case (gorm+mux)? I've check some articles, but most of them are testing the http connect status but not for SQL.
And my function do not have the return value, or I need to rewrite the function to have a return value before I can test it?
below is the test structure in my mind:
func TestGetURL(t *testing.T) {
//set const answer for this test
//set up the mock sql connection
//call getURL()
//check if equal with answer using assert
}
Update
According to #Emin Laletovic answer
Now I have a prototype of my testGetURL. Now I have new questions on it.
func TestGetURL(t *testing.T) {
//set const answer for this test
testQuery := `SELECT * FROM "urls" WHERE id=1`
id := 1
//set up the mock sql connection
testDB, mock, err := sqlmock.New()
if err != nil {
panic("sqlmock.New() occurs an error")
}
// uses "gorm.io/driver/postgres" library
dialector := postgres.New(postgres.Config{
DSN: "sqlmock_db_0",
DriverName: "postgres",
Conn: testDB,
PreferSimpleProtocol: true,
})
db, err = gorm.Open(dialector, &gorm.Config{})
if err != nil {
panic("Cannot open stub database")
}
//mock the db.Find function
rows := sqlmock.NewRows([]string{"id", "url", "expire_at", "short_url"}).
AddRow(1, "http://somelongurl.com", "some_date", "http://shorturl.com")
mock.ExpectQuery(regexp.QuoteMeta(testQuery)).
WillReturnRows(rows).WithArgs(id)
//create response writer and request for testing
mockedRequest, _ := http.NewRequest("GET", "/1", nil)
mockedWriter := httptest.NewRecorder()
//call getURL()
getURL(mockedWriter, mockedRequest)
//check values in mockedWriter using assert
}
In the code, I mock the request and respone with http, httptest libs.
I run the test, but it seems that the getURL function in main.go cannot receive the args I pass in, see the pic below.
when db.find called, mock.ExpectQuery receive it and start to compare it, so far so good.
db.Find(&url, params["id"])
mock.ExpectQuery(regexp.QuoteMeta(testQuery)).WillReturnRows(rows).WithArgs(id)
According to the testing log, it shows that when db.Find triggerd, it only excute SELECT * FROM "urls" but not I expected SELECT * FROM "urls" WHERE "urls"."id" = $1.
But when I test db.Find on local with postman and log the SQL syntax out, it can be excute properly. see pic below.
In summary, I think the problem is the responeWriter/request I put in getURL(mockedWriter, mockedRequest) are wrong, and it leads that getURL(w http.ResponseWriter, r *http.Request) cannot work as we expect.
Please let me know if I missing anything~
Any idea or way to rewrite the code would be help, thank you!
If you just want to test the SQL string that db.Find returns, you can use the DryRun feature (per documentation).
stmt := db.Session(&Session{DryRun: true}).Find(&url, params["id"]).Statement
stmt.SQL.String() //returns SQL query string without the param value
stmt.Vars // contains an array of input params
However, to write a test for the getURL function, you could use sqlmock to mock the results that would be returned when executing the db.Find call.
func TestGetURL(t *testing.T) {
//set const answer for this test
testQuery := "SELECT * FROM `urls` WHERE `id` = $1"
id := 1
//create response writer and request for testing
//set up the mock sql connection
testDB, mock, err := sqlmock.New()
//handle error
// uses "gorm.io/driver/postgres" library
dialector := postgres.New(postgres.Config{
DSN: "sqlmock_db_0",
DriverName: "postgres",
Conn: testDB,
PreferSimpleProtocol: true,
})
db, err = gorm.Open(dialector, &gorm.Config{})
//handle error
//mock the db.Find function
rows := sqlmock.NewRows([]string{"id", "url", "expire_at", "short_url"}).
AddRow(1, "http://somelongurl.com", "some_date", "http://shorturl.com")
mock.ExpectQuery(regexp.QuoteMeta(testQuery)).
WillReturnRows(rows).WithArgs(id)
//call getURL()
getUrl(mockedWriter, &mockedRequest)
//check values in mockedWriter using assert
}
This Post and Emin Laletovic are really helps me alot.
I think I get the answer to this qeustion.
Let's recap this questioon. First, I'm using gorm for postgresql and mux for http services and build a CRUD service.
I need to write a unit test to check if my database syntax is correct (we assuming that the connection is statusOK), so we focus on how to write a unit test for SQL syntax.
But the handler function in main.go don't have return value, so we need to use mock-sql/ ExpectQuery(), this function will be triggered when the db.Find() inside getURL(). By doing this, we dont have to return a value to check if it match our target or not.
The problem I met in Update is fixed by This Post, building an unit test with mux, but that post is focusing on status check and return value.
I set the const answer for this test, the id variable is what we expect to get. Noticed that $1 I don't know how to change it, and I've try many times to rewrite but SQL syntax is still return $1, maybe it is some kind of constraint I dont know.
//set const answer for this test
testQuery := `SELECT * FROM "urls" WHERE "urls"."id" = $1`
id := "1"
I set the value pass into the getURL() by doint this
//set the value send into the function
vars := map[string]string{
"id": "1",
}
//create response writer and request for testing
mockedWriter := httptest.NewRecorder()
mockedRequest := httptest.NewRequest("GET", "/{id}", nil)
mockedRequest = mux.SetURLVars(mockedRequest, vars)
Finally, we call mock.ExpectationsWereMet() to check if anything went wrong.
if err := mock.ExpectationsWereMet(); err != nil {
t.Errorf("SQL syntax is not match: %s", err)
}
Below is my test code:
func TestGetURL(t *testing.T) {
//set const answer for this test
testQuery := `SELECT * FROM "urls" WHERE "urls"."id" = $1`
id := "1"
//set up the mock sql connection
testDB, mock, err := sqlmock.New()
if err != nil {
panic("sqlmock.New() occurs an error")
}
// uses "gorm.io/driver/postgres" library
dialector := postgres.New(postgres.Config{
DSN: "sqlmock_db_0",
DriverName: "postgres",
Conn: testDB,
PreferSimpleProtocol: true,
})
db, err = gorm.Open(dialector, &gorm.Config{})
if err != nil {
panic("Cannot open stub database")
}
//mock the db.Find function
rows := sqlmock.NewRows([]string{"id", "url", "expire_at", "short_url"}).
AddRow(1, "url", "date", "shorurl")
//try to match the real SQL syntax we get and testQuery
mock.ExpectQuery(regexp.QuoteMeta(testQuery)).WillReturnRows(rows).WithArgs(id)
//set the value send into the function
vars := map[string]string{
"id": "1",
}
//create response writer and request for testing
mockedWriter := httptest.NewRecorder()
mockedRequest := httptest.NewRequest("GET", "/{id}", nil)
mockedRequest = mux.SetURLVars(mockedRequest, vars)
//call getURL()
getURL(mockedWriter, mockedRequest)
//check result in mockedWriter mocksql built function
if err := mock.ExpectationsWereMet(); err != nil {
t.Errorf("SQL syntax is not match: %s", err)
}
}
And I run two tests with args(1, 1) and args(1, 2), and it works fine. see pic below(please ignore the chinese words)
My application mostly consists of CRUDs to/from MongoDB using mongo-go-drive package. This function is one of gRPC server services and all it does is calling database method action.GetProducts(ctx) and it returns *mongo.cursor. Then the result is decoded. For each document, I put the document content into a singular product struct, then append it to products slices (the GetProductsResponse struct is made using gRPC proto repeated GetProductResponse type). After appending all product into GetProductsResponse, I return the response to gRPC client.
I am also new to testing in general, how should I break down the function and do the mocking (how to mock the cursor?) for unit testing? Is it even necessary in the first place to do unit test on the function even though all it does is appending the result, or should I just go straight for the integration test and skip the unit test since it involves database I/O?
func (s *Server) GetProducts(ctx context.Context, in *pb.EmptyRequest) (*pb.GetProductsResponse, error) {
cursor, err := action.GetProducts(ctx)
if err != nil {
return nil, err
}
products := pb.GetProductsResponse{}
res := model.Product{}
for cursor.Next(ctx) {
// Convert document to above struct
err := cursor.Decode(&res)
if err != nil {
return nil, fmt.Errorf("failed to decode document: %v", err)
}
product := &pb.GetProductResponse{ProductId: res.Product_id.Hex(), Name: res.Name, Price: res.Price, Qty: int32(res.Qty)}
products.Products = append(products.Products, product)
}
return &products, nil
}
If you interact with the DB is not unit testing anymore, because you're integrating with another external system.
Anyway, I use to define my "repository" layer function this way:
package repo
var FetchUserById = func(id string) (*model.User, error){
// here the real logic
return user, err
}
and then, when I have to test my "service" layer logic, I would mock the entire "repository" layer this way:
repo.FetchUserById = func(id string) (*model.User, err) {
return myMockedUser, nil
}
In program bellow I have two routers. One is working at localhost:3000 and acts like a public access point. It also may send requests with data to another local address which is localhost:8000 where data is being processed. Second router is working at localhost:8000 and handles processing requests for the first router.
Problem
The first router sends a request with context to the second using http.NewRequestWithContext() function. The value is being added to the context and the context is added to request. When request arrives to the second router it does not have value that was added previously.
Some things like error handling are not being written to not post a wall of code here.
package main
import (
"bytes"
"context"
"net/http"
"github.com/go-chi/chi"
"github.com/go-chi/chi/middleware"
)
func main() {
go func() {
err := http.ListenAndServe(
"localhost:3000",
GetDataAndSolve(),
)
if err != nil {
panic(err)
}
}()
go func() {
err := http.ListenAndServe( // in GetDataAndSolve() we send requests
"localhost:8000", // with data for processing
InternalService(),
)
if err != nil {
panic(err)
}
}()
// interrupt := make(chan os.Signal, 1)
// signal.Notify(interrupt, syscall.SIGTERM, syscall.SIGINT)
// <-interrupt // just a cool way to close the program, uncomment if you need it
}
func GetDataAndSolve() http.Handler {
r := chi.NewRouter()
r.Use(middleware.Logger)
r.Get("/tasks/str", func(rw http.ResponseWriter, r *http.Request) {
// receiving data for processing...
taskCtx := context.WithValue(r.Context(), "str", "strVar") // the value is being
postReq, err := http.NewRequestWithContext( // stored to context
taskCtx, // context is being given to request
"POST",
"http://localhost:8000/tasks/solution",
bytes.NewBuffer([]byte("something")),
)
postReq.Header.Set("Content-Type", "application/json") // specifying for endpoint
if err != nil { // what we are sending
return
}
resp, err := http.DefaultClient.Do(postReq) // running actual request
// pls, proceed to Solver()
// do stuff to resp
// also despite arriving to middleware without right context
// here resp contains a request with correct context
})
return r
}
func Solver(next http.Handler) http.Handler { // here we end up after sending postReq
return http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
if r.Context().Value("str").(string) == "" {
return // the request arrive without "str" in its context
}
ctxWithResult := context.WithValue(r.Context(), "result", mockFunc(r.Context()))
next.ServeHTTP(rw, r.Clone(ctxWithResult))
})
}
func InternalService() http.Handler {
r := chi.NewRouter()
r.Use(middleware.Logger)
r.With(Solver).Post("/tasks/solution", emptyHandlerFunc)
return r
}
Your understanding of context is not correct.
Context (simplifying to an extent and in reference to NewRequestWithContext API), is just an in-memory object using which you can control the lifetime of the request (Handling/Triggering cancellations).
However your code is making a HTTP call, which goes over the wire (marshaled) using HTTP protocol. This protocol doesn't understand golang's context or its values.
In your scenario, both /tasks/str and /tasks/solution are being run on the same server. What if they were on different servers, probably different languages and application servers as well, So the context cannot be sent across.
Since the APIs are within the same server, maybe you can avoid making a full blown HTTP call and resort to directly invoking the API/Method. It might turn out to be faster as well.
If you still want to send additional values from context, then you'll have to make use of other attributes like HTTP Headers, Params, Body to send across the required information. This can provide more info on how to serialize data from context over HTTP.
How do I create a proper mongo based application in Go using the official driver(go.mongodb.org/mongo-driver/mongo)? I have a MongoConnect() and MongoDisconnect(client) function to create a connection and delete it. But, it's not too efficient and starts leaking FD as the app has got around 40 functions and finding all the missed MongoDisconnect() becomes hectic.
The current MongoConnect and MongoDisconnect are as follows.
func MongoConnect() (*mongo.Client, error) {
clientOptions := options.Client().ApplyURI("mongodb://localhost:27017")
client, err := mongo.Connect(context.TODO(), clientOptions)
if err != nil {
Logger(err)
return nil, err
}
err = client.Ping(context.TODO(), nil)
if err != nil {
Logger(err)
return nil, err
}
return client, err
}
func MongoDisconnect(client *mongo.Client) {
_ = client.Disconnect(context.TODO())
}
I am looking for a method that would still use MongoConnect() to create connections and would automatically kill the client without the usage of MongoDisconnect().
PS. Other methods that are better than the above requirement are also welcome
I'm not sure that there is an 'efficient' way to fix the underlying issue, you probably will need to look at all the places where you've called MongoConnect() and ensure you have a corresponding MongoDisconnect().
In saying that, what you might want to look at is implemententing the right pattern for connecting to databases.
Generally speaking, if your database driver takes care of managing connections for you then you should create the connection once and just pass it around as needed.
You could also defer the closing of that connection to a go routine which would close it once it was no longer needed (when you're application is shutting down).
Here is a code snippet of how this is implemented:
// =========================================================================
// Start Database
log.Println("main: Initializing database support")
db, err := database.Open(database.Config{
User: cfg.DB.User,
Password: cfg.DB.Password,
Host: cfg.DB.Host,
Name: cfg.DB.Name,
DisableTLS: cfg.DB.DisableTLS,
})
if err != nil {
return errors.Wrap(err, "connecting to db")
}
defer func() {
log.Printf("main: Database Stopping : %s", cfg.DB.Host)
db.Close()
}()
I didn't write this code and its part of a larger project scaffold which has some other nice patterns for web applications.
Ultimate service
I'm fetching a document from MongoDB and passing it into function transform, e.g.
var doc map[string]interface{}
err := collection.FindOne(context.TODO(), filter).Decode(&doc)
result := transform(doc)
I want to write unit tests for transform, but I'm not sure how to mock a response from MongoDB. Ideally I want to set something like this up:
func TestTransform(t *testing.T) {
byt := []byte(`
{"hello": "world",
"message": "apple"}
`)
var doc map[string]interface{}
>>> Some method here to Decode byt into doc like the code above <<<
out := transform(doc)
expected := ...
if diff := deep.Equal(expected, out); diff != nil {
t.Error(diff)
}
}
One way would be to json.Unmarshal into doc, but this sometimes gives different results. For example, if the document in MongoDB has an array in it, then that array is decoded into doc as a bson.A type not []interface{} type.
A member from my team recently found out there is a hidden gem inside the official MongoDB driver for GO: https://pkg.go.dev/go.mongodb.org/mongo-driver#v1.9.1/mongo/integration/mtest. Although the package is in experimental mode and there is no backward compatibility guaranteed for it, it can help you to perform unit testing, at least with this version of the driver.
You can check this cool article with plenty of examples of how to use it: https://medium.com/#victor.neuret/mocking-the-official-mongo-golang-driver-5aad5b226a78. Additionally, here is the repository with the code samples for this article: https://github.com/victorneuret/mongo-go-driver-mock.
So, based in your example and the samples from the article I think you could try something like the following (of course, you might need to tweak and experiment with this):
func TestTransform(t *testing.T) {
mt := mtest.New(t, mtest.NewOptions().ClientType(mtest.Mock))
defer mt.Close()
mt.Run("find & transform", func(mt *mtest.T) {
myollection = mt.Coll
expected := myStructure{...}
mt.AddMockResponses(mtest.CreateCursorResponse(1, "foo.bar", mtest.FirstBatch, bson.D{
{"_id", expected.ID},
{"field-1", expected.Field1},
{"field-2", expected.Field2},
}))
response, err := myFindFunction(expected.ID)
if err != nil {
t.Error(err)
}
out := transform(response)
if diff := deep.Equal(expected, out); diff != nil {
t.Error(diff)
}
})
}
Alternatively, you can perform a more real testing and in an automated way via integration testing with Docker containers. There are a few good packages that could help you with this:
https://github.com/ory/dockertest
https://github.com/testcontainers/testcontainers-go
I have followed this approach with dockertest library to automate a full integration testing environment that could be setUp and tearDown via the go test -v -run Integration command. See a full example here: https://github.com/AnhellO/learn-dockertest/tree/master/mongo.
Hope this helps.
The best solution to write testable could would be to extract your code to a DAO or Data-Repository. You would define an interface which would return what you need. This way, you can just used a Mocked Version for testing.
// repository.go
type ISomeRepository interface {
Get(string) (*SomeModel, error)
}
type SomeRepository struct { ... }
func (r *SomeRepository) Get(id string) (*SomeModel, error) {
// Handling a real repository access and returning your Object
}
When you need to mock it, just create a Mock-Struct and implement the interface:
// repository_test.go
type SomeMockRepository struct { ... }
func (r *SomeRepository) Get(id string) (*SomeModel, error) {
return &SomeModel{...}, nil
}
func TestSomething() {
// You can use your mock as ISomeRepository
var repo *ISomeRepository
repo = &SomeMockRepository{}
someModel, err := repo.Get("123")
}
This is best used with some kind of dependency-injection, so passing this repository as ISomeRepository into the function.
Using monkey library to hook any function from mongo driver.
For example:
func insert(collection *mongo.Collection) (int, error) {
ctx, _ := context.WithTimeout(context.Background(), 10*time.Second)
u := User{
Name: "kevin",
Age: 20,
}
res, err := collection.InsertOne(ctx, u)
if err != nil {
log.Printf("error: %v", err)
return 0, err
}
id := res.InsertedID.(int)
return id, nil
}
func TestInsert(t *testing.T) {
var c *mongo.Collection
var guard *monkey.PatchGuard
guard = monkey.PatchInstanceMethod(reflect.TypeOf(c), "InsertOne",
func(c *mongo.Collection, ctx context.Context, document interface{}, opts ...*options.InsertOneOptions) (*mongo.InsertOneResult, error) {
guard.Unpatch()
defer guard.Restore()
log.Printf("record: %+v, collection: %s, database: %s", document, c.Name(), c.Database().Name())
res := &mongo.InsertOneResult{
InsertedID: 100,
}
return res, nil
})
collection := client.Database("db").Collection("person")
id, err := insert(collection)
require.NoError(t, err)
assert.Equal(t, id, 100)
}