SpecFlow.Assist.Dynamic–maxing out with Simple.Data

· November 2, 2011

SpecFlow.Assist.Dynamic came about from my own need when I wrote something that used Simple.Data.

I saw the power and simplicity (duh!) in Simple.Data by using dynamics. And I started to thinking on how it could be used in SpecFlow to further simplify and shorten up the code in my steps.

This is the third and final post on SpecFlow.Assist.Dynamic. Again this is not the formal documentation. It can be found here. These are just my personal preferences and thoughts on how to use it. This time with Simple.Data. And it won’t be long.

SpecFlow and Simple.Data

First you should check out Darren Cauthons post on using SpecFlow and simple data together. It shows the great use of a lightweight, simple data access framework in SpecFlow.

As I said in my earlier post test data management is something that you often have to handle in your scenarios. Simple.Data is more than up to the job.

SpecFlow.Assist.Dynamic and Simple.Data

So I thought I’ll take Darrens example from the post and rewrite it using SpecFlow.Assist.Dynamic.

Here is the feature Darren is using, updated to be a bit more readable for a non-technical person (spaces in headers):

1: Scenario: Submit a valid create account form
2:  Given the following accounts exist
3:      | First name | Last name | Email   |
4:      | Howard     | Roark     | h@r.com |
5:  When I submit the following Create Account form
6:      | Field      | Value   |
7:      | First name | John    |
8:      | Last name  | Galt    |
9:      | Email      | j@g.com |
10:  Then the following accounts should exist
11:      | First name | Last name | Email   |
12:      | Howard     | Roark     | h@r.com |
13:      | John       | Galt      | j@g.com |

SpecFlow.Assist.Dynamic will convert the “First name” header into “FirstName” as you might remember. As will the statically typed SpecFlow.Assist table helpers if I remember correctly.

I first create the Simple.Data dynamic database object in the a method marked with the attribute BeforeScenario. And while I’m there I clear out the Accounts table as well:

1: private static dynamic DB { get; set; }
3: [BeforeScenario]
4: public void Setup()
5: {
6:     DB = Database.Open();
7:     DB.Accounts.DeleteAll();
8: }

In the Given step I’m using the step argument transformations that comes with SpecFlow.Assist.Dynamic and get a IList<dynamic> from the Table as parameter to the step definition. This can then be sent right on to the Simple.Data database object, like this:

1:[Given(@"the following accounts exist")]
2: public void x(IList<dynamic> accounts)
3: {
4:     DB.Accounts.Insert(accounts);
5: }

Bom! Database table loaded – one line.

In the When-step I have faked up a controller. Here I am using SpecFlow.Assist.Dynamic to get a single instance, again with the use of the step argument transformations; this time it will turn the Table into a dynamic:

1: [When(@"I submit the following Create Account form")]
2: public void y(dynamic account)
3: {
4:     var fakeController = new FakeAccountController(DB);
5:     fakeController.Create(account);
6: }

The actual FakeAccountController looks like this:

1: public class FakeAccountController
2: {
3:     private readonly dynamic _database;
5:     public FakeAccountController(dynamic database)
6:     {
7:         _database = database;
8:     }
10:     public void Create(dynamic account)
11:     {
12:         _database.Accounts.Insert(account);
13:     }
14: }

Finally the Then-step compares the Table from the scenario to the content of the database. For now I just compare the number of rows, which is super lazy… but it’s ten o’clock and I’m tired…

1:  [Then(@"the following accounts should exist")]
2: public void z(IList<dynamic> expectedAccounts)
3: {
4:     IList<dynamic> accountsInDb = DB.Accounts.All().ToList();
6:     // Assert that they are the same
7:     expectedAccounts.Count.Should().Equal(accountsInDb.Count);
8:     // ...
9: }


So by marrying the great Simple.Data framework with my small efforts in SpecFlow.Assist.Dynamic we can now move clear-text scenario data from and to the database very easily and with just a few lines of code.

I hope you found this helpful and the SpecFlow.Assist.Dynamic could be useful for you.

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