public async Task UpdateOutputFilesGeneratesWarningWhenAdditionalOutputFileIsEmpty() // To encourage developer to cleanup their code generator
{
await UIThreadDispatcher.Invoke <Task>(async delegate
{
this.output.Content.Clear();
this.output.Content.Append(WhiteSpaceText);
this.provider.UpdateOutputFiles(this.input.FileNames[1], new[] { this.output });
await this.SimulateCustomTool();
ErrorItem warning = ErrorItems.Single(item => item.FileName == this.input.FileNames[1]);
StringAssert.Contains(warning.Description, this.output.Path);
Assert.AreEqual(vsBuildErrorLevel.vsBuildErrorLevelMedium, warning.ErrorLevel);
});
}