simple_test.go

package service

import (
	"testing"
)

type preCheckMock struct {
	userExistsMock func(email string) bool
}

func (p preCheckMock) UserExists(email string) bool {
	return p.userExistsMock(email)
}

func TestCheckUserExist(t *testing.T) {
	user := User{
		Name:     "John Doe",
		Email:    "[email protected]",
		UserName: "john",
	}
	err := RegisterUser(user, NewRegistrationPreChecker())
	if err == nil {
		t.Error("Expected Register User to throw an error, got nil")
	}
}

func TestRegisterUser(t *testing.T) {
	user := User{
		Name:     "John Doe",
		Email:    "[email protected]",
		UserName: "john",
	}

	regPreCond := preCheckMock{func(email string) bool { return false }}

	err := RegisterUser(user, regPreCond)
	if err != nil {
		t.Fatal(err)
	}

	regPreCond = preCheckMock{func(email string) bool { return true }}

	err = RegisterUser(user, regPreCond)
	if err == nil {
		t.Error("Expected Register User to throw an error, got nil")
	}
}