log-test-output.md

Logging Output from Scenario Steps

Since this framework relies on Xunit for execution, it's natural that you can output messages from your scenario steps (i.e. test methods) through ITestOutputHelper interface, which is defined within Xunit framework.

To acquire instance of the output, simply define a constructor argument of type ITestOutputHelper. This is optional, and you don't have to define such argument at all times; Only when you need to output string messages from your methods.

For example:

[FeatureFile(@"./TestOutput/OutputMessages.feature")]
public sealed class OutputMessages : Feature
{
    private readonly ITestOutputHelper _testOutputHelper;

    public OutputMessages(ITestOutputHelper testOutputHelper)
    {
        _testOutputHelper = testOutputHelper;
    }

    [Given(@"output is available")]
    public void Given_output_is_available()
    {
        Assert.NotNull(_testOutputHelper);
    }

    [When(@"I log message ""(.+)""")]
    public void Given_message(string message)
    {
        _testOutputHelper.WriteLine(message);
    }

    [Then(@"I should see it in the output")]
    public void Then_I_should_see_it_in_the_output()
    {
        //check the output.
    }
}

Notice that the constructor has an argument ITestOutputHelper testOutputHelper, which can be used later on (as in the Given_message method above) to output messages to the standard test output pane.

---

Obviously, this example assumes that there is a feature file which has corresponding steps matching these methods. Such as this one:

File: OutputMessages.feature

Feature: Output Messages
	In order to help see what is received by scenario steps
	As a BDD tester
	I want to output messages from steps

Scenario: Log Strings
	Given output is available
	When I log message "hello word"
	Then I should see it in the output