Grabbing the output sent to Console.Out from within a unit test?
I am building a unit test in C# with NUnit, and I'd like to test that the main progra开发者_运维百科m actually outputs the right output depending on the command line arguments.
Is there a way from an NUnit test method that calls Program.Main(...)
to grab everything written to Console.Out
and Console.Error
so that I can verify against it?
You can redirect Console.In
, Console.Out
and Console.Error
to custom StringWriters, like this
[TestMethod]
public void ValidateConsoleOutput()
{
using (StringWriter sw = new StringWriter())
{
Console.SetOut(sw);
ConsoleUser cu = new ConsoleUser();
cu.DoWork();
string expected = string.Format("Ploeh{0}", Environment.NewLine);
Assert.AreEqual<string>(expected, sw.ToString());
}
}
See this blog post for full details.
You can use this simple class to get the output with a using statement:
public class ConsoleOutput : IDisposable
{
private StringWriter stringWriter;
private TextWriter originalOutput;
public ConsoleOutput()
{
stringWriter = new StringWriter();
originalOutput = Console.Out;
Console.SetOut(stringWriter);
}
public string GetOuput()
{
return stringWriter.ToString();
}
public void Dispose()
{
Console.SetOut(originalOutput);
stringWriter.Dispose();
}
}
Here is an example how to use it:
using (var consoleOutput = new ConsoleOutput())
{
target.WriteToConsole(text);
Assert.AreEqual(text, consoleOutput.GetOuput());
}
you can find more detailed information and a working code sample on my blog post here - Getting console output within a unit test.
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