gorm/preload_test.go

package gorm_test

import (
	"encoding/json"
	"log"
	"reflect"
	"testing"
)

func getPreloadUser(name string) *User {
	return getPreparedUser(name, "Preload")
}

func checkUserHasPreloadData(user User, t *testing.T) {
	u := getPreloadUser(user.Name)
	if user.BillingAddress.Address1 != u.BillingAddress.Address1 {
		t.Error("Failed to preload user's BillingAddress")
	}

	if user.ShippingAddress.Address1 != u.ShippingAddress.Address1 {
		t.Error("Failed to preload user's ShippingAddress")
	}

	if user.CreditCard.Number != u.CreditCard.Number {
		t.Error("Failed to preload user's CreditCard")
	}

	if user.Company.Name != u.Company.Name {
		t.Error("Failed to preload user's Company")
	}

	if len(user.Emails) != len(u.Emails) {
		t.Error("Failed to preload user's Emails")
	} else {
		var found int
		for _, e1 := range u.Emails {
			for _, e2 := range user.Emails {
				if e1.Email == e2.Email {
					found++
					break
				}
			}
		}
		if found != len(u.Emails) {
			t.Error("Failed to preload user's email details")
		}
	}
}

func TestPreload(t *testing.T) {
	user1 := getPreloadUser("user1")
	DB.Save(user1)

	preloadDB := DB.Where("role = ?", "Preload").Preload("BillingAddress").Preload("ShippingAddress").
		Preload("CreditCard").Preload("Emails").Preload("Company")
	var user User
	preloadDB.Find(&user)
	checkUserHasPreloadData(user, t)

	user2 := getPreloadUser("user2")
	DB.Save(user2)

	user3 := getPreloadUser("user3")
	DB.Save(user3)

	var users []User
	preloadDB.Find(&users)

	for _, user := range users {
		checkUserHasPreloadData(user, t)
	}

	var users2 []*User
	preloadDB.Find(&users2)

	for _, user := range users2 {
		checkUserHasPreloadData(*user, t)
	}

	var users3 []*User
	preloadDB.Preload("Emails", "email = ?", user3.Emails[0].Email).Find(&users3)

	for _, user := range users3 {
		if user.Name == user3.Name {
			if len(user.Emails) != 1 {
				t.Errorf("should only preload one emails for user3 when with condition")
			}
		} else if len(user.Emails) != 0 {
			t.Errorf("should not preload any emails for other users when with condition")
		}
	}
}

func TestNestedPreload(t *testing.T) {
	log.SetFlags(log.Lshortfile)
	// Struct: Level3
	{
		type (
			Level1 struct {
				ID       uint
				Value    string
				Level2ID uint
			}
			Level2 struct {
				ID       uint
				Level1   Level1
				Level3ID uint
			}
			Level3 struct {
				ID     uint
				Level2 Level2
			}
		)
		DB.DropTableIfExists(&Level3{})
		DB.DropTableIfExists(&Level2{})
		DB.DropTableIfExists(&Level1{})
		if err := DB.AutoMigrate(&Level3{}, &Level2{}, &Level1{}).Error; err != nil {
			panic(err)
		}

		want := Level3{Level2: Level2{Level1: Level1{Value: "value"}}}
		if err := DB.Create(&want).Error; err != nil {
			panic(err)
		}

		var got Level3
		if err := DB.Preload("Level2").Preload("Level2.Level1").Find(&got).Error; err != nil {
			panic(err)
		}

		if !reflect.DeepEqual(got, want) {
			t.Errorf("got %s; want %s", toJSONString(got), toJSONString(want))
		}
	}
	{
		type (
			Level1 struct {
				ID       uint
				Value    string
				Level2ID uint
			}
			Level2 struct {
				ID       uint
				Level1s  []Level1
				Level3ID uint
			}
			Level3 struct {
				ID      uint
				Level2s []Level2
			}
		)
		DB.DropTableIfExists(&Level3{})
		DB.DropTableIfExists(&Level2{})
		DB.DropTableIfExists(&Level1{})
		if err := DB.AutoMigrate(&Level3{}, &Level2{}, &Level1{}).Error; err != nil {
			panic(err)
		}

		want := Level3{
			Level2s: []Level2{
				{
					Level1s: []Level1{
						{Value: "value1"},
						{Value: "value2"},
					},
				},
				{
					Level1s: []Level1{
						{Value: "value3"},
					},
				},
			},
		}
		if err := DB.Create(&want).Error; err != nil {
			panic(err)
		}

		var got Level3
		if err := DB.Preload("Level2s.Level1s").Find(&got).Error; err != nil {
			panic(err)
		}

		if !reflect.DeepEqual(got, want) {
			t.Errorf("got %s; want %s", toJSONString(got), toJSONString(want))
		}
	}
	{
		type (
			Level1 struct {
				ID       uint
				Value    string
				Level2ID uint
			}
			Level2 struct {
				ID       uint
				Level1   Level1
				Level3ID uint
			}
			Level3 struct {
				ID      uint
				Level2s []Level2
			}
		)
		DB.DropTableIfExists(&Level3{})
		DB.DropTableIfExists(&Level2{})
		DB.DropTableIfExists(&Level1{})
		if err := DB.AutoMigrate(&Level3{}, &Level2{}, &Level1{}).Error; err != nil {
			panic(err)
		}

		want := Level3{
			Level2s: []Level2{
				{Level1: Level1{Value: "value1"}},
				{Level1: Level1{Value: "value2"}},
			},
		}
		if err := DB.Create(&want).Error; err != nil {
			panic(err)
		}

		var got Level3
		if err := DB.Preload("Level2s.Level1").Find(&got).Error; err != nil {
			panic(err)
		}

		if !reflect.DeepEqual(got, want) {
			t.Errorf("got %s; want %s", toJSONString(got), toJSONString(want))
		}
	}
	{
		type (
			Level1 struct {
				ID       uint
				Value    string
				Level2ID uint
			}
			Level2 struct {
				ID       uint
				Level1s  []Level1
				Level3ID uint
			}
			Level3 struct {
				ID     uint
				Level2 Level2
			}
		)
		DB.DropTableIfExists(&Level3{})
		DB.DropTableIfExists(&Level2{})
		DB.DropTableIfExists(&Level1{})
		if err := DB.AutoMigrate(&Level3{}, &Level2{}, &Level1{}).Error; err != nil {
			panic(err)
		}

		want := Level3{
			Level2: Level2{
				Level1s: []Level1{
					Level1{Value: "value1"},
					Level1{Value: "value2"},
				},
			},
		}
		if err := DB.Create(&want).Error; err != nil {
			panic(err)
		}

		var got Level3
		if err := DB.Preload("Level2.Level1s").Find(&got).Error; err != nil {
			panic(err)
		}

		if !reflect.DeepEqual(got, want) {
			t.Errorf("got %s; want %s", toJSONString(got), toJSONString(want))
		}
	}

	// Slice: []Level3
	{
		type (
			Level1 struct {
				ID       uint
				Value    string
				Level2ID uint
			}
			Level2 struct {
				ID       uint
				Level1   Level1
				Level3ID uint
			}
			Level3 struct {
				ID     uint
				Level2 Level2
			}
		)
		DB.DropTableIfExists(&Level3{})
		DB.DropTableIfExists(&Level2{})
		DB.DropTableIfExists(&Level1{})
		if err := DB.AutoMigrate(&Level3{}, &Level2{}, &Level1{}).Error; err != nil {
			panic(err)
		}

		want := make([]Level3, 2)
		want[0] = Level3{Level2: Level2{Level1: Level1{Value: "value"}}}
		if err := DB.Create(&want[0]).Error; err != nil {
			panic(err)
		}
		want[1] = Level3{Level2: Level2{Level1: Level1{Value: "value2"}}}
		if err := DB.Create(&want[1]).Error; err != nil {
			panic(err)
		}

		var got []Level3
		if err := DB.Preload("Level2").Preload("Level2.Level1").Find(&got).Error; err != nil {
			panic(err)
		}

		if !reflect.DeepEqual(got, want) {
			t.Errorf("got %s; want %s", toJSONString(got), toJSONString(want))
		}
	}
	{
		type (
			Level1 struct {
				ID       uint
				Value    string
				Level2ID uint
			}
			Level2 struct {
				ID       uint
				Level1s  []Level1
				Level3ID uint
			}
			Level3 struct {
				ID      uint
				Level2s []Level2
			}
		)
		DB.DropTableIfExists(&Level3{})
		DB.DropTableIfExists(&Level2{})
		DB.DropTableIfExists(&Level1{})
		if err := DB.AutoMigrate(&Level3{}, &Level2{}, &Level1{}).Error; err != nil {
			panic(err)
		}

		want := make([]Level3, 2)
		want[0] = Level3{
			Level2s: []Level2{
				{
					Level1s: []Level1{
						{Value: "value1"},
						{Value: "value2"},
					},
				},
				{
					Level1s: []Level1{
						{Value: "value3"},
					},
				},
			},
		}
		if err := DB.Create(&want[0]).Error; err != nil {
			panic(err)
		}
		want[1] = Level3{
			Level2s: []Level2{
				{
					Level1s: []Level1{
						{Value: "value3"},
						{Value: "value4"},
					},
				},
				{
					Level1s: []Level1{
						{Value: "value5"},
					},
				},
			},
		}
		if err := DB.Create(&want[1]).Error; err != nil {
			panic(err)
		}

		var got []Level3
		if err := DB.Preload("Level2s.Level1s").Find(&got).Error; err != nil {
			panic(err)
		}

		if !reflect.DeepEqual(got, want) {
			t.Errorf("got %s; want %s", toJSONString(got), toJSONString(want))
		}
	}
	{
		type (
			Level1 struct {
				ID       uint
				Value    string
				Level2ID uint
			}
			Level2 struct {
				ID       uint
				Level1   Level1
				Level3ID uint
			}
			Level3 struct {
				ID      uint
				Level2s []Level2
			}
		)
		DB.DropTableIfExists(&Level3{})
		DB.DropTableIfExists(&Level2{})
		DB.DropTableIfExists(&Level1{})
		if err := DB.AutoMigrate(&Level3{}, &Level2{}, &Level1{}).Error; err != nil {
			panic(err)
		}

		want := make([]Level3, 2)
		want[0] = Level3{
			Level2s: []Level2{
				{Level1: Level1{Value: "value1"}},
				{Level1: Level1{Value: "value2"}},
			},
		}
		if err := DB.Create(&want[0]).Error; err != nil {
			panic(err)
		}
		want[1] = Level3{
			Level2s: []Level2{
				{Level1: Level1{Value: "value3"}},
				{Level1: Level1{Value: "value4"}},
			},
		}
		if err := DB.Create(&want[1]).Error; err != nil {
			panic(err)
		}

		var got []Level3
		if err := DB.Preload("Level2s.Level1").Find(&got).Error; err != nil {
			panic(err)
		}

		if !reflect.DeepEqual(got, want) {
			t.Errorf("got %s; want %s", toJSONString(got), toJSONString(want))
		}
	}
	{
		type (
			Level1 struct {
				ID       uint
				Value    string
				Level2ID uint
			}
			Level2 struct {
				ID       uint
				Level1s  []Level1
				Level3ID uint
			}
			Level3 struct {
				ID     uint
				Level2 Level2
			}
		)
		DB.DropTableIfExists(&Level3{})
		DB.DropTableIfExists(&Level2{})
		DB.DropTableIfExists(&Level1{})
		if err := DB.AutoMigrate(&Level3{}, &Level2{}, &Level1{}).Error; err != nil {
			panic(err)
		}

		want := make([]Level3, 2)
		want[0] = Level3{
			Level2: Level2{
				Level1s: []Level1{
					Level1{Value: "value1"},
					Level1{Value: "value2"},
				},
			},
		}
		if err := DB.Create(&want[0]).Error; err != nil {
			panic(err)
		}
		want[1] = Level3{
			Level2: Level2{
				Level1s: []Level1{
					Level1{Value: "value3"},
					Level1{Value: "value4"},
				},
			},
		}
		if err := DB.Create(&want[1]).Error; err != nil {
			panic(err)
		}

		var got []Level3
		if err := DB.Preload("Level2.Level1s").Find(&got).Error; err != nil {
			panic(err)
		}

		if !reflect.DeepEqual(got, want) {
			t.Errorf("got %s; want %s", toJSONString(got), toJSONString(want))
		}
	}
}

func toJSONString(v interface{}) []byte {
	r, _ := json.MarshalIndent(v, "", "  ")
	return r
}