t.Fatalf("should only find no pet with invalid conditions, but got %v", count)
	}

	// Count
	AssertAssociationCount(t, user, "Pets", 2, "")

	// Append
	pet := Pet{Name: "pet-has-many-append"}

	if err := DB.Model(&user2).Association("Pets").Append(&pet); err != nil {
		t.Fatalf("Error happened when append account, got %v", err)
	}

	if pet.ID == 0 {
		t.Fatalf("Pet's ID should be created")
	}