A testable Go Service with repository (storage + finders)

testable_service_poc.go

package main

import (
  "fmt"
)


type Thing struct {
  Uuid         string
  Description  string
}

type Store interface {
  findRawThing(string, string)(string, error)
}

///====
type TestStore struct {}

func NewTestStore(config string) (*TestStore, error){
  return &TestStore{}, nil
}

func (ts *TestStore) findRawThing(uuid string, another string)(string, error) {
  fmt.Println(another)
  return "this is a raw TEST thing", nil
}

//*****

type RealStore struct {
  config  string
}

func NewRealStore(config string) (*RealStore, error){
  return &RealStore{config: config}, nil
}

func (ts *RealStore) findRawThing(uuid string, another string)(string, error) {
  fmt.Println(another)
  return "this is a raw thing coming from REAL db", nil
}


///====


type ThingRepository interface {
  FindThing(string)(*Thing, error)
}

type Thinger struct {}

func (tr Thinger) FindThing(uuid string) func(Store)(*Thing, error) {
  return func(st Store)(*Thing, error) {
    rawThing, _ :=  st.findRawThing(uuid, "another_param")
    return &Thing{Uuid: uuid, Description: rawThing}, nil
  }
}

//====

type Repository struct {
  store    Store
  thinger  Thinger
}

func (tr *Repository) FindThing(uuid string)(*Thing, error) {
  return tr.thinger.FindThing(uuid)(tr.store)
}

func NewTestThingRepository(config string)(ThingRepository, error) {
  testStore, _ := NewTestStore(config)
  return &Repository{store: testStore, thinger: Thinger{}}, nil
}

func NewRealThingRepository(config string)(ThingRepository, error) {
  realStore, _ := NewRealStore(config)
  return &Repository{store: realStore, thinger: Thinger{}}, nil
}


//====

func main() {
    testRepo, _ := NewTestThingRepository("config")
    aTestThing, _ := testRepo.FindThing("c0ff33b4be")
    fmt.Printf("TEST_REPO => %+v\n", aTestThing)

    realRepo, _ := NewRealThingRepository("config")
    aRealThing, _ := realRepo.FindThing("c0ff33b4be")
    fmt.Printf("REAL_REPO => %+v\n", aRealThing)
}