FormatException in Verifies when test fail

[Roxeez]

Bug Type Please pick one:

• [ ] a check failed to detect an error (false negative), i.e. a test is green while it should be red.
• [ ] a check raised un existing error (false positive), i.e a test is red while it should be green.
• [ ] an error message is invalid/incomplete (please provide samples)
• [x] a ran into an exception.
• [ ] other.

Describe the bug I'm getting this exception when my test fail (in Verifies scope)

System.FormatException
Input string was not in a correct format.
   at System.Text.StringBuilder.AppendFormatHelper(IFormatProvider provider, String format, ReadOnlySpan`1 args)
   at System.Text.StringBuilder.AppendFormat(String format, Object arg0, Object arg1)
   at NFluent.Extensibility.FluentMessage.ToString()
   at NFluent.Kernel.CheckLogic`1.EndCheck()
   at NFluent.CheckMember`2.Verifies(Action`1 func)

Check.That(result).IsInstanceOf<OkObjectResult>()
    .Which
    .WhichMember(x => x.Value)
    .Verifies(x =>
    {
        x.IsNull();
    });

To Reproduce

public class MyEntity
{

}

public class MyExample
{
    public object Value { get; init; }
}

var value = new MyExample
{
    Value = new List<MyEntity>()
};

// Assert
Check.That(value).IsInstanceOf<MyExample>()
    .Which
    .WhichMember(x => x.Value)
    .Verifies(x =>
    {
        x.IsNull();
    });

Expected behavior I expected it toshow me explicitly what's the problem instead of a FormatException

Desktop (please complete the following information):

• NFluent version: 3.0.1.352
• Net Version: .NET 7
• IDE: Rider 2023.1.4

[dupdob]

hi thanks for reporting this. I have reproduced and fixed this issue. I will be releasing a fix in the coming days

[dupdob]

Hi I did publish V3.0.2.327-beta that contains the fix. Could you please test it and report ? if the problem is fixed, I will publish an official release.

[Roxeez]

Yes looks like it's fixed !