Sample Attribute

This attribute is used to provide sample data or its source.

The available properties are as follows.

Property	Description
Data	Specifies sample data using parameters of a constructor. If the Source property is specified, this is ignored.
Description	Specifies a description of sample data. If the Source property is specified, this is ignored.
Source	Specifies a source type of sample data. This type must implement the ISampleDataSource interface and have a parameterless constructor.

For example:

[Specification("LoginAuthentication specification")]
class LoginAuthenticationSpec
{
    [Example("Login authentication is failed")]
    [Sample(null, "pass", Description = "When a user id is null")]
    [Sample("", "pass", Description = "When a user id is empty")]
    [Sample("user", null, Description = "When a password is null")]
    [Sample("user", "", Description = "When a password is empty")]
    [Sample("user", "pass", Description = "When a user id or password is invalid")]
    void Ex01(string userId, string password)
    {
        ...
    }
}

When a source is specified, its source type must implement the ISampleDataSource interface. The ISampleDataSource interface defines the GetData method that returns an instance that implements the IEnumerable interface and does not have a parameter. The object that is contained by the IEnumerable has properties that indicate sample data. The property name is equal to a parameter name of the specified fixture method. Its case is ignored. If you want to specify a description of the sample fixture, define a property whose name is 'Description'.

For example:

[Specification("LoginAuthentication specification")]
class LoginAuthenticationSpec
{
    [Example("Login authentication is failed")]
    [Sample(Source = typeof(FailedLoginSampleDataSource))]
    void Ex01(string userId, string password)
    {
        ...
    }
}

class FailedLoginSampleDataSource : ISampleDataSource
{
    IEnumerable ISampleDataSource.GetData()
    {
        yield return new { Description = "When a user id is null", UserId = null, Password = "pass" };
        yield return new { Description = "When a user id is empty", UserId = string.Empty, Password = "pass" };
        yield return new { Description = "When a password is null", UserId = "user", Password = null };
        yield return new { Description = "When a password is empty", UserId = "user", Password = string.Empty };
        yield return new { Description = "When a user id or password is invalid", UserId = "user", Password = "pass" };
    }
}