QuickCheckr 0.0.5

<img src='icon.png' width='40' align='top'/> QuickCheckr

CSI: .NET

Property-based testing for the pragmatic.

Example

Buggy Code:

public class BugHouse
{
    private int count;
    public bool Run(int number)
    {
        if (count == 5) throw new Exception("Here's Johnny");
        if (number == 6 && count != 3) count++;
        if (count >= 3) count++;
        return true;
    }
}

The Checkr:

from bughouse in Trackr.Stashed(() => new BugHouse())
from number in Checkr.Input("number", Fuzzr.Int())
from output in Checkr.Act("BugHouse.Run", () => bughouse.Run(number))
from expect in Checkr.Expect("Returns true", () => output)
select Case.Closed;

Reports:

------------------------------------------------------------
 Test:                    Example
 Location:                CreateReadMe.cs:26:1
 Original failing run:    85 executions
 Minimal failing case:    5 executions (after 82 shrinks)
 Seed:                    1141724745
 ------------------------------------------------------------
  Executed: BugHouse.Run (3 Times)
   - Input: number = 6
 ------------------------------------------------------------
  Executed: BugHouse.Run (2 Times)
 ===========================================================================
  !! Exception Thrown: System.Exception: Here's Johnny
   at QuickCheckr.Tests.CreateReadMe.BugHouse.Run(Int32 number) in CreateReadMe.cs:line 69
   at QuickCheckr.Tests.CreateReadMe.<>c__DisplayClass2_0.GetCheckr() in CreateReadMe.cs:line 57
   at QuickCheckr.Checkr.<>c__DisplayClass8_1`1.TryCatch() in CheckrAct.cs:line 69
   at QuickCheckr.UnderTheHood.TheCatcher.InTheCheckr[T](CheckrState state, Func`1 func, Action`1 onException) in UnderTheHood\TheCatcher.cs:line 14
 ===========================================================================
 Passed Expectations
 - Returns true: 84x
 ------------------------------------------------------------

Highlights

• LINQ-based workflow: Build tests using familiar query expressions.
• Shrinking: Reduce randomly generated scenarios to minimal failing cases.
• Stateful testing: Pools, stashed objects, and multi-step behaviours supported out of the box.
• Deterministic: Reproducible runs using seeds.
• Built for Devs: Transparency and traceability as a first-class concern.

Installation

QuickCheckr is available on NuGet:

Install-Package QuickCheckr

Or via the .NET CLI:

dotnet add package QuickCheckr

Documentation

QuickCheckr is in the process of being fully documented, with real, executable examples for every feature, and every statement in the docs is backed by a test.

• Start here: Checkr-ing Things Out
• Then see it catch a real bug: Bolting Horses

Full Guide: This is a work in progess. Follow the link to find out what's coming next.

Roadmap

• Elm-style helpful exceptions.
• Full Guide + Reference documentation.
• Additional diagnostic flows.
• True async execution throughout the engine.

Dependencies

• QuickFuzzr: For random input generation.
• QuickPulse.Show: For stringifying any C# object or value.
• QuickPulse: Implicit through QuickPulse.Show. But also used for diagnostics filtering and transformations.

The Wonder(ing) Years

Why QuickCheckr Exists

License

This project is licensed under the MIT License.