You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: structs_test.go
    path of file: ./repos/koanf/providers/structs
    
    the code of the file until where you have to start completion: package structs

import (
	"reflect"
	"testing"
)

type parentStruct struct {
	Name   string   
    
func TestStructs_Read(t *testing.T) {
	type fields struct {
		s     interface{}
		tag   string
		delim string
	}
	tests := []struct {
		name    string
		fields  fields
		want    map[string]interface{}
		wantErr bool
	}{
		{
			name: "read",
			fields: fields{
				s: testStruct{
					Type:  "json",
					Empty: make(map[string]string),
					Parent1: parentStruct{
						Name: "parent1",
						ID:   1234,
						Child1: childStruct{
							Name:  "child1",
							Type:  "json",
							Empty: make(map[string]string),
							Grandchild1: grandchildStruct{
								Ids: []int{1, 2, 3},
								On:  true,
							},
						},
					},
				},
				tag: "koanf",
			},
			want: map[string]interface{}{
				"type":  "json",
				"empty": map[string]string{},
				"parent1": map[string]interface{}{
					"child1": map[string]interface{}{
						"empty": map[string]string{},
						"type":  "json",
						"name":  "child1",
						"grandchild1": map[string]interface{}{
							"on":  true,
							"ids": []int{1, 2, 3},
						},
					},
					"name": "parent1",
					"id":   1234,
				},
			},
			wantErr: false,
		},
		{
			name: "read delim struct",
			fields: fields{
				s: testStructWithDelim{
					Endpoint: "test_endpoint",
					Username: "test_username",
					Password: "test_password",
				},
				tag:   "koanf",
				delim: ".",
			},
			want: map[string]interface{}{
				"conf_creds": map[string]interface{}{
					"password": "test_password",
					"username": "test_username",
				},
				"conf_endpoint": "test_endpoint",
			},
			wantErr: false,
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			s := &Structs{
				s:     tt.fields.s,
				tag:   tt.fields.tag,
				delim: tt.fields.delim,
			}
			got, err := s.Read()
			if (err != nil) != tt.wantErr {
				t.Errorf("Structs.Read() error = %v, wantErr %v", err, tt.wantErr)
				return
			}
			if !reflect.DeepEqual(got, tt.want) {
				t.Errorf("Structs.Read() = \n%#v\nwant \n%#v\n", got, tt.want)
			}
		})
	}
}