Specflow ignores When step in F# step assembly - f#

Question

I am using VS2010, SpecFlow 1.9.0, NUnit 2.6.2 and ReSharper 7.1. I have a feature file taken from the example:
Feature: SpecFlowFeature1
In order to avoid silly mistakes
As a math idiot
I want to be told the sum of two numbers
#mytag
Scenario: Add two numbers
Given I have entered 50 into the calculator
And I have entered 70 into the calculator
When I press the add button
Then the result should be 120 on the screen
I have implemented the step definitions in a separate F# assembly:
[<TechTalk.SpecFlow.Binding>]
module StepDefinitions
open TechTalk.SpecFlow
open NUnit.Framework
let [<Given>] ``I have entered (.*) into the calculator`` (a: int) =
ScenarioContext.Current.Pending()
let [<When>] ``I press the add button`` =
ScenarioContext.Current.Pending()
let [<Then>] ``the result should be (.*) on the screen`` (r: int) =
ScenarioContext.Current.Pending()
I have told SpecFlow where to find them via the stepAssemblies tag in app.config
However, when I run the test, it finds the Given and Then steps, but not the When step. The error I get is:
No matching step definition found for one or more steps.
using System;
using TechTalk.SpecFlow;
namespace MyNamespace
{
[Binding]
public class StepDefinitions
{
[When(#"I press the add button")]
public void WhenIPressTheAddButton()
{
ScenarioContext.Current.Pending();
}
}
}
Given I have entered 50 into the calculator
-> pending: StepDefinitions.I have entered (.*) into the calculator(50)
And I have entered 70 into the calculator
-> skipped because of previous errors
When I press the add button
-> No matching step definition found for the step. Use the following code to create one:
[When(#"I press the add button")]
public void WhenIPressTheAddButton()
{
ScenarioContext.Current.Pending();
}
Then the result should be 120 on the screen
-> skipped because of previous errors
Have I gone wrong somewhere, or is there a bug with F# support?

Answer 1

The correct translation of the C# is actually
let [<When>] ``I press the add button``() =
ScenarioContext.Current.Pending()
Note the extra (). As this was missing in the original version, the function had a different signature which meant that it wasn't found.