public async Task LoadSymbolsAsync()
        {
            var modules = new List <SbModule>()
            {
                Substitute.For <SbModule>(),
                Substitute.For <SbModule>(),
                Substitute.For <SbModule>(),
                Substitute.For <SbModule>(),
            };

            _target.GetNumModules().Returns(modules.Count);
            for (int i = 0; i < modules.Count; i++)
            {
                _target.GetModuleAtIndex(i).Returns(modules[i]);
            }

            var task           = Substitute.For <ICancelable>();
            var symbolSettings =
                new SymbolInclusionSettings(true, new List <string>(), new List <string>());
            var moduleFileLoadRecorder = Substitute.For <IModuleFileLoadMetricsRecorder>();
            await _attachedProgram.LoadModuleFilesAsync(
                symbolSettings, true, task, moduleFileLoadRecorder);

            await _moduleFileLoader.Received(1).LoadModuleFilesAsync(
                Arg.Is <IList <SbModule> >(l => l.SequenceEqual(modules)), symbolSettings, true, task,
                moduleFileLoadRecorder);
        }