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: cache_flags_test.go
    path of file: ./repos/trivy/pkg/flag
    
    the code of the file until where you have to start completion: package flag_test

import (
	"testing"
	"time"

	"github.
    
func TestCacheOptions_CacheBackendMasked(t *testing.T) {
	type fields struct {
		backend string
	}
	tests := []struct {
		name   string
		fields fields
		want   string
	}{
		{
			name: "redis cache backend masked",
			fields: fields{
				backend: "redis://root:password@localhost:6379",
			},
			want: "redis://****@localhost:6379",
		},
		{
			name: "redis cache backend masked does nothing",
			fields: fields{
				backend: "redis://localhost:6379",
			},
			want: "redis://localhost:6379",
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			c := &flag.CacheOptions{
				CacheBackend: tt.fields.backend,
			}

			assert.Equal(t, tt.want, c.CacheBackendMasked())
		})
	}
}