I use Specflow a lot. It is a simple way to describe specifications for a software system. Working with days, however, never look nice in Gherkin style. Consider the following given:
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Given a user created '16-02-2023'.
It just needs to read nicer, something like:
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Given a user created 'yesterday'.
By default, the string ‘yesterday’ is not a DateTime value. It is possible to overwrite existing value retrievers of Specflow (or to create your own). To commentate the use of ‘yesterday’ or ‘tomorrow’, I have made an overwrite of the default DateTimeValueRetriever. A binding (or Hook) is needed to unregister the default one and register the SpecialDateTimeValueRetriever. The complete code is displayed below:
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using TechTalk.SpecFlow.Assist;
namespace TechTalk.SpecFlow.Assist.ValueRetrievers;
public class SpecialDateTimeValueRetriever : DateTimeValueRetriever
{
public static readonly DateTime Today = DateTime.UtcNow;
private readonly Dictionary<string, DateTime> specialDates = new Dictionary<string, DateTime>
{
{ "TODAY", Today },
{ "TOMORROW", Today.AddDays(1) },
{ "YESTERDAY", Today.AddDays(-1) },
{ "DAY AFTER TOMORROW", Today.AddDays(2) },
{ "DAY BEFORE YESTERDAY", Today.AddDays(-2) },
{ "IN AN HOUR", Today.AddHours(1) },
{ "AN HOUR AGO", Today.AddHours(-1) }
};
protected override DateTime GetNonEmptyValue(string value)
{
return specialDates.TryGetValue(value.ToUpper(), out DateTime dateTime)
? dateTime
: base.GetNonEmptyValue(value);
}
}
[Binding]
public static class SpecialDateTimeModelHook
{
[BeforeTestRun]
public static void BeforeTestRun()
{
Service.Instance.ValueRetrievers.Unregister<DateTimeValueRetriever>();
Service.Instance.ValueRetrievers.Register(new SpecialDateTimeValueRetriever());
}
}
Specflow itself describes how to create your own custom IValueRetriever here and the location of their own ValueRetrieves are in Github.