Timecop 1.0.1

Timecop - Easy Date and Time Testing in C#

Timecop is a small library that helps you test DateTime in a static, thread-safe, ambient context.

Timecop targets .NET Standard 2.0, has no external dependencies, and can be used with .NET Framework 4.5+ and any version of .NET and .NET Core.

Timecop has been inspired by the timecop Ruby gem.

Installation

You can install Timecop from NuGet using the .NET CLI:

dotnet add package Timecop

Basic usage

Timecop allows you to freeze and travel in time. Just use the Clock class instead of DateTimeto get the current time via Now or UtcNow properties, and manipulate time with the Timecop class in your tests.

string Greet()
{
    var timeOfDay = Clock.Now.Hour switch // Use Clock instead of DateTime
    {
        >= 0 and < 6 => "night",
        >= 6 and < 12 => "morning",
        >= 12 and < 18 => "afternoon",
        _ => "evening"
    };

    return $"Good {timeOfDay}!";
}

// freeze at 2pm local time:
using var tc = Timecop.Frozen(o => o.At(14,0,0).LocalTime()); 

Greet(); // Good afternoon!

// travel to 8pm local time:
tc.TravelBy(TimeSpan.FromHours(6)); 

Greet(); // Good evening!

Available methods

Freezing and resuming time

Time is frozen with either an instance Freeze or a static Frozen method, both having the same set of signatures. The instance Freeze freezes the instance of Timecop, the static Frozen creates an already frozen instance.

Frozen time doesn't run for your tests until you call Resume or dispose the Timecop instance:

using var tc = Timecop.Frozen(1990, 12, 2, 14, 38, 51, DateTimeKind.Local);

Clock.Now; // 1990-12-02 14:38:51

Thread.Sleep(TimeSpan.FromSeconds(3));

Clock.Now; // 1990-12-02 14:38:51 - still the same value

tc.Resume();

Thread.Sleep(TimeSpan.FromSeconds(3));

Clock.Now; // 1990-12-02 14:38:54 - time has changed

Both Freeze and Frozen have multiple overloads:

// freeze at the current instant:
tc.Freeze();

// freeze at the specified DateTime:
tc.Freeze(new DateTime(1990, 12, 2, 14, 38, 51, DateTimeKind.Utc));

// freeze at the specified date and time:
tc.Freeze(1990, 12, 2, 14, 38, 51, DateTimeKind.Utc);

// freeze at the specified date:
tc.Freeze(1990, 12, 2, DateTimeKind.Utc);

// freeze at the specified date or time or both:
tc.Freeze(o => o.On(1990, 12, 2)
                .At(14, 13, 51)
                .LocalTime());

Traveling in time

Use the TravelBy method to travel forward and backward in time:

using var tc = Timecop.Frozen(1990, 12, 2, 14, 38, 51, DateTimeKind.Local);

tc.TravelBy(TimeSpan.FromDays(1));

Clock.Now; // 1990-12-03 14:38:51 - one day in the future

License

Timecop was created by Dmytro Khmara and is licensed under the MIT license.