SpecFlow + AutoMapper + AutoPoco = Steckbrett.SpecsSupport

Steckbrett.SpecsSupport is a library of helper “steps” to easily generate model instances in SpecFlow specifications. It integrates AutoPoco and AutoMapper libraries.

Apart from configuring the model, there is only one extra requirement to use these helpers in specifications: In order to activate the model mapping configurations, you have to tag the feature with @model_mapping

Let's see the whole thing in action using a project that provides sample usage features. In App.config, SpecFlow is instructed to include steps defined in Steckbrett.SpecsSupport.dll assembly (<stepAssemblies> section). A simple sample model is configured in ModelMappingEvents.cs . Below you can see some sample scenarios: the steps shown in red are helpers defined in Steckbrett.SpecsSupport.dll ; underscored fragments are step arguments.

A sample scenario of (pseudo-)random instance generation (see more in AutoPoco.feature):

Scenario: Generating a consecutive number of random instances

 

Given 3 random instances of Customer

Given 2 random instances of Customer

Then I should have 5 random instances of Customer

 

Some sample scenarios of table mappings (see more in AutoMapper.feature):

Scenario: Mapping table to Customer

 

Given the following instance of Customer:

    | FirstName | LastName |

    | John      | Doe      |

 

Then I should have a Customer called John Doe

 

Scenario: Mapping tables to Order and Details, add to parent list with implicit typing

 

Given the following instance of Order:

    | Id |

    |  1 |

 

And the following instances added to Details of Order 1:

    | Price | Quantity |

    |   150 |        2 |

    |   200 |        1 |

 

When I calculate Order 1 total

 

Then I should get total 500 in Order 1

Scenario: Mapping self-referencing table to Customer

 

Given the following instance of Customer:

    | Id | FirstName | LastName | Parent |

    |  1 | John      | Doe      |   null |

    |  2 | John      | Doe      |      1 |

 

Then I should have Customer 1 referencing to no parent customer

And I should have Customer 2 referencing to parent customer 1

Scenario: Mapping from file

 

Given instances of Customer from file Data\Customers.gherkin

Then I should have 15 instances of Customer

 

You can access the model instances from your steps using extension methods on ScenarioContext. For example:

 

[Then(@"I should get total (.+) in Order (\d+)")]

public void ThenIShouldGetTotalInOrder(decimal total, int orderId)

{

    var order = ScenarioContext.Current.InstanceById<Order>(orderId);

 

    Assert.That(order.Total, Is.EqualTo(total));

}

 

[Then(@"the first instance of Customer should have Id (\d+)")]

public void ThenTheFirstInstanceOfCustomerShouldHaveId(int id)

{

    var customer = ScenarioContext.Current.InstancesOf<Customer>().FirstOrDefault();

 

    Assert.That(customer, Is.Not.Null);

    Assert.That(customer.Id, Is.EqualTo(id));

}

 

That's all folks! All the trickiness of model instantiation is hidden behind the helper steps so you can focus on writing gorgeous specs.

Your feedback is welcome.

_______________________________________________________

UPDATE 2010-05-27: Inspired by Pickle (thanks to Jonas Bandi for the tip), I’ve just added some assertions steps. See Assertions.feature for examples.

_______________________________________________________

PS: "Steckbrett" is the name of the in-house framework we use in our company. It's German for "plugboard". :-)