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: blob_test.go
    path of file: ./repos/vald/internal/config
    
    the code of the file until where you have to start completion: //
// Copyright (C) 2019-2024 vdaas.org vald team <vald@vdaas.org>
//
// Licensed under the Apache License, Version 2.0 (the "License");
// You may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or ag
    
func TestBlobStorageType_String(t *testing.T) {
	type want struct {
		want string
	}
	type test struct {
		name       string
		bst        BlobStorageType
		want       want
		checkFunc  func(want, string) error
		beforeFunc func()
		afterFunc  func()
	}
	defaultCheckFunc := func(w want, got string) error {
		if !reflect.DeepEqual(got, w.want) {
			return errors.Errorf("got: \"%#v\",\n\t\t\t\twant: \"%#v\"", got, w.want)
		}
		return nil
	}
	tests := []test{
		{
			name: "return s3 when the bst is S3",
			bst:  S3,
			want: want{
				want: "s3",
			},
		},
		{
			name: "return cloud_storage when the bst is CloudStorage",
			bst:  CloudStorage,
			want: want{
				want: "cloud_storage",
			},
		},
		{
			name: "return unknown when the bst is empty",
			want: want{
				want: "unknown",
			},
		},
		{
			name: "return unknown when the bst is invalid storage type",
			bst:  BlobStorageType(100),
			want: want{
				want: "unknown",
			},
		},
	}

	for _, tc := range tests {
		test := tc
		t.Run(test.name, func(tt *testing.T) {
			defer goleak.VerifyNone(tt, goleakIgnoreOptions...)
			if test.beforeFunc != nil {
				test.beforeFunc()
			}
			if test.afterFunc != nil {
				defer test.afterFunc()
			}
			checkFunc := test.checkFunc
			if test.checkFunc == nil {
				checkFunc = defaultCheckFunc
			}

			got := test.bst.String()
			if err := checkFunc(test.want, got); err != nil {
				tt.Errorf("error = %v", err)
			}
		})
	}
}