Go: organize your tests with "suits" to get setup/teardown for group of tests and make initialization without using init() function and any testing frameworks!

service_test.go

package service

import (
  "fmt"
  "testing"
  "github.com/jinzhu/gorm"
  ".../service/model"
)

type test func(t *testing.T)

// CoolServiceSuite - group of CoolService tests 
func CoolServiceSuite(s CoolService, testDB *gorm.DB) []test {
  return []test{
    ServiceMethodFirst(s, testDB),
    ServiceMethodNext(s, testDB),
  }
}

// ServiceMethodFirst - make test for CoolService.MethodFirst()
func ServiceMethodFirst(s CoolService, testDB *gorm.DB) test {
  return func(t *testing.T) {
    t.Log("TEST service.CoolService.MethodFirst()")
    value, err := s.MethodFirst()
    if err != nil {
      t.Errorf("Unexpected error: %v", err)
    }
    if value != "first is cool" {
      t.Errorf("Unexpected result: %s", value)
    }
    // check DB changes with testDB
  }
}

// ServiceMethodNext - make test for CoolService.MethodNext()
func ServiceMethodNext(s CoolService, testDB *gorm.DB) test {
  return func(t *testing.T) {
    // test something
  }
}

// setupDB - creates independent db connection to track changes made by CoolService,
// returns *gorm.DB only as example
func setupDB() *gorm.DB {
  // read config, find DSN ...
  db, err := gorm.Open(...)
  if err != nil {
    panic(err)
  }
  // prepare something or make migrations ...
  return db
}

func TestCoolService(t *testing.T) {
  testDB := setupDB()
  
  // additional setup ...
  
  defer func() {
    // tear down
    testDB.Close()
    // ...
  }()
  
  cool, err := NewCoolService()
  for i, test := range CoolServiceSuite(cool, testDB) {
    t.Run(fmt.Sprintf("test #%d", i), test)
  }
}