SpecFlow assist - create instance from table

Question

I'm trying out the specFlow assist and not sure how would one create class property from table. Imagine I have this class:

public class Tracking 
{
    public string Category { get; set; }
}

public class ODARequest
{
    public string Title { get; set; }
    public string Name { get; set; }
    public Tracking Tracking { get; set; }
}

My Given scenario is next:

Scenario: Successfully create an account
Given I have entered the following data into the ODA form:
    | Field                  | Value            |
    | Title                  | Mr               |
    | Name                   | Andy             |
    | Tracking Category      | MDA              |


public void GivenIHaveEnteredTheFollowingDataIntoTheODAForm(Table table)
{
    var request = table.CreateInstance<ODARequest>();
}

The Tracking property will not be populated. Anyone know how to describe Tracking.Category in the table for this situation?

Answer 1

I've been hitting this problem and been thinking how to do it with a single step.

Scenario: Successfully create an account
Given I have entered the following data into the ODA form:
    |Title | Name | Category|
    | Mr   | Andy | MDA     |

public void GivenIHaveEnteredTheFollowingDataIntoTheODAForm(Table table)
{
    var request = table.CreateInstance<ODARequest>();
    request.Tracking = table.CreateInstance<Tracking>();
}

How it works: You may call "CreateInstance" for each complex property you have so specflow will create you an instance. So you can have a single table with properties from different types.

By doing so you won't need a different step and the need of sharing data between the steps.

The drawback is that you may end up with a huge table if your class has a lot of properties with different types.

Note: As @Alex M commented it there is a risk when the classes are having a property with same name. What will happen actually is that both instances will get the same value due to the property name match on both classes.

Answer 2

I haven't been able to find a way of getting specflow to map "CreateInstance" to non-standard data types properties.

However, in this case you could at least use a StepArgumentTransformation as follows:

    [Given(@"I have entered the following data into the ODA form:")]
    public void GivenIHaveEnteredTheFollowingDataIntoTheODAForm(ODARequest request)
    {
        Assert.IsNotNull(request.Tracking);
    }

    [StepArgumentTransformation(@".*")]
    public ODARequest StringToTracking(Table input)
    {
        return new ODARequest() { 
            Title = input.Rows.Single(row => row["Title"])["value"],
            Name = input.Rows.Single(row => row["Name"])["value"],
            Tracking = new Tracking() 
                { Category = input.Rows.Single(row => row["Field"] == "Tracking Category")["Value"] }
            };
    }

With a little work you could tidy the stepargumenttransformation up to accept each parameter as optional (rather than having "single()" throw if it is omitted).

I feel like there really ought to be a better way to do this, more like your original suggested code. Hope this is helpful.

Answer 3

Another possibility without modifying the specflow assist itself is to separate the subclass properties into separate Given. Can be as per below example:

Scenario: Successfully create an account
Given I have entered the following data into the ODA form:
| Field                  | Value            |
| Title                  | Mr               |
| Name                   | Andy             |
And the tracking info as:
| Tracking Category      | MDA              |

then my step definitions would be as:

[Given(@"I have entered the following data into the ODA form:")]
public void GivenIHaveEnteredTheFollowingDataIntoTheODAForm(Table table)
{
    var request = table.CreateInstance<ODARequest>();
    ScenarioContext.Current.Set(request, "request");
}
[Given(@"the tracking info as:")]
public void GivenTheTrackingInfoAs(Table table)
{
    var request = ScenarioContext.Current.Get<ODARequest>("request");
    request.TrackingFields = table.CreateInstance<Tracking>();
}

Otherwise the possibility is to contribute to specflow assist development.