How to set up individual tracing / logging with SpecFlow

Question

For my SpecFlow tests, I want to setup an individual logging / tracing of the test progress during the execution of tests. E.g. i want to write

• all passed / failed steps
• started / ended scenarios
• started / ended features

to the windows event log (in order to synchronize it with event log messages generated by other system components during the test).

I tried to use the [BeforeFeature], [BeforeScenario], [BeforeStep] Hooks for doing that, but it turned out that I do not have all the required information within this hooks. E.g. i do not know how to get the current text line of the current step executed (including line information, etc.) or the result (failed / passed) of the current step.

Is there a way to get this information within those hooks or in any other way during the execution of the test?

If not: Is there a way to customize the trace output created by Specflow in any other way?

Answer 1

In order to provide a custom implementation of ITestTracer you should create a plugin for SpecFlow.

Create a class library project with a name CustomTracer.SpecflowPlugin. CustomTracer is your name of choice for plugin.

Then put the following code into your new assembly

[assembly: RuntimePlugin(typeof(CustomTracer.SpecflowPlugin.CustomTracerPlugin))]

namespace CustomTracer.SpecflowPlugin
{
    public class CustomTracerPlugin : IRuntimePlugin
    {
        public void RegisterDependencies(ObjectContainer container)
        {

        }

        public void RegisterCustomizations(ObjectContainer container, RuntimeConfiguration runtimeConfiguration)
        {
            container.RegisterTypeAs<CustomTracer, ITestTracer>();
        }

        public void RegisterConfigurationDefaults(RuntimeConfiguration runtimeConfiguration)
        {

        }
    }

    public class CustomTracer : ITestTracer
    {
        // Your implementation here
    }
}

Compile assembly and put in the project folder where your specs are (where .csprog file is).

Edit app.config, specFlow section to include:

<plugins>
  <add name="CustomTracer" path="." type="Runtime"/>
</plugins>

That is it. Your plugin should load and your custom ITracer implementation should be called during scenario execution. You can even debug it, if you run scenarios under debug.

Answer 2

Finally, after some investigation, i found out that you can replace the DefaultTraceListener by your own implementation by implementing the Interface ITraceListener:

public class foo:  TechTalk.SpecFlow.Tracing.ITraceListener
{
    public void WriteTestOutput(string message)
    {
        EventLog.WriteEntry("mysource", "output: " + message);
    }

    public void WriteToolOutput(string message)
    {
        EventLog.WriteEntry("mysource", "specflow: " + message);
    }
}

And modifying your App.config configuration by adding this to the "specflow" section:

<trace traceSuccessfulSteps="true"
       traceTimings="false"
       minTracedDuration="0:0:0.1"
       listener="MyNamespace.foo, MyAssemblyName"/>

However, this is more a "workaround" for me since I don't have typed information (e.g. of the StepInstance class) and I have to rely or modify the output formatting of SpecFlow.

I would prefer replacing the TestTracer (ITestTracer) implementation by my own one in some way, but i did not find a way to do this. Does anyone now how to do it?

Answer 3

In Specflow 2.1 its a little different.

Instead of:

public class CustomTracerPlugin : IRuntimePlugin
{
    public void RegisterDependencies(ObjectContainer container)
    {

    }

    public void RegisterCustomizations(ObjectContainer container, RuntimeConfiguration runtimeConfiguration)
    {
        container.RegisterTypeAs<CustomTracer, ITestTracer>();
    }

    public void RegisterConfigurationDefaults(RuntimeConfiguration runtimeConfiguration)
    {

    }
}

Do this:

public class CustomTracerPlugin : IRuntimePlugin
{
    public void Initialize(RuntimePluginEvents runtimePluginEvents, RuntimePluginParameters runtimePluginParameters)
    {
        runtimePluginEvents.CustomizeTestThreadDependencies += (sender, args) => { args.ObjectContainer.RegisterTypeAs<CustomTracer, ITestTracer>(); };
    }
}

Every thing else is the same as Vladimir Perevalovs answer.

Answer 4

To register a custom ITestTracer in SpecFlow 3.x:

[assembly: RuntimePlugin(typeof(CustomTracerPlugin))]

public class CustomTracerPlugin : IRuntimePlugin
{
    public void Initialize(
        RuntimePluginEvents runtimePluginEvents,
        RuntimePluginParameters runtimePluginParameters,
        UnitTestProviderConfiguration unitTestProviderConfiguration)
    {
        runtimePluginEvents.CustomizeGlobalDependencies +=
            (s, ea) => ea.ObjectContainer.RegisterTypeAs<CustomTracer, ITestTracer>();
    }
}

public class CustomTracer : ITestTracer
{
    ...
}