The problem with splitting tests into separate files

[ku9n (Serhii Kuyanov)]

I have written a large number of tests for my API in one file, and everything works fine there. Now I want to separate these tests into individual files, and no matter what I’ve tried, as you can see in the [repository] (GitHub - ku9nov/SAU: Simple Auto Updater service written in Golang.), I’m using the handler module, so I can’t place the tests in the handler module as there is a cyclic dependency. Also, for the tests to pass, there must be a connection to the database, so connecting to it is mandatory for all functions.

With moving the tests to a separate folder, I haven’t had any success either.

Let’s consider the simplest example: this is my server_test.go file.

package main

var (
	client        *mongo.Client
	appDB         db.AppRepository
	mongoDatabase *mongo.Database
	configDB      connstring.ConnString
	s3Endpoint    string
)

func TestMain(m *testing.M) {
	// Set up resources before running tests
	setup()
	// Run the tests
	code := m.Run()
	teardown()
	os.Exit(code)
}

func copyFile(src, dst string) {
	input, err := os.ReadFile(src)
	if err != nil {
		logrus.Errorf("Failed to read the file: %v", err)
		return
	}

	err = os.WriteFile(dst, input, 0644)
	if err != nil {
		logrus.Errorf("Failed to copy the file: %v", err)
		return
	}
}

func removeFile(filename string) {
	err := os.Remove(filename)
	if err != nil {
		logrus.Errorf("Failed to remove the file: %v", err)
		return
	}
}

func setup() {
	viper.SetConfigType("env")
	viper.SetConfigName(".env")
	// set the configuration file path
	viper.AddConfigPath(".")
	// read in the configuration file
	if err := viper.ReadInConfig(); err != nil {
		panic(err)
	}
	// Create a single database connection
	flagMap := map[string]interface{}{
		"migration":     true,
		"rollback":      false,
		"user_name":     "admin",
		"user_password": "password",
	}
	s3Endpoint = viper.GetString("S3_ENDPOINT")
	client, configDB = mongod.ConnectToDatabase(viper.GetString("MONGODB_URL_TESTS"), flagMap)
	appDB = mongod.NewAppRepository(&configDB, client)
	mongoDatabase = client.Database(configDB.Database)
	copyFile("LICENSE", "testapp.dmg")
	copyFile("LICENSE", "testapp.pkg")

}

func teardown() {
	adminsCollection := mongoDatabase.Collection("admins")
	filter := bson.M{"username": "admin"}

	// Delete the admin user from the collection
	_, err := adminsCollection.DeleteOne(context.TODO(), filter)
	if err != nil {
		logrus.Errorf("Failed to remove admin user: %v", err)
	}
	log.Println("Successfully removed admin user.")
	client.Disconnect(context.Background())
	log.Println("MongoDB is disconnected.")
	removeFile("testapp.dmg")
	removeFile("testapp.pkg")
}

func TestHealthCheck(t *testing.T) {

	router := gin.Default()
	w := httptest.NewRecorder()

	handler := handler.NewAppHandler(client, appDB, mongoDatabase)
	router.GET("/health", func(c *gin.Context) {
		handler.HealthCheck(c)
	})

	req, _ := http.NewRequest("GET", "/health", nil)

	// Serve the request using the Gin router.
	router.ServeHTTP(w, req)

	// Check the response status code.
	assert.Equal(t, http.StatusOK, w.Code)

	// Check the response body.
	expected := `{"status":"healthy"}`
	assert.Equal(t, expected, w.Body.String())
}

How can I correctly move the TestHealthCheck function to tests/info_test.go? Of course, passing the database connection parameters to it…