Add custom assertion for type already handled by FA

[lonix1]

I found this sample that creates a custom assertion for MyClass:

public class MyClassAssertions : ReferenceTypeAssertions<MyClass, MyClassAssertions>
{
    public MyClassAssertions(MyClass subject) : base(subject) { }
    protected override string Identifier => nameof(MyClass);
}

public static class Extensions
{
    public static MyClassAssertions Should(this MyClass myClass) => new MyClassAssertions(myClass);
}

That allows:

myClass.Should()....

But how do you add a custom assertion for a type that already has assertions, e.g. DateTime:

myDateTime.Should().BeFooBarBaz();

[dennisdoomen]

Add an extension method that extends DateTimeAssertions. We do this in

fluentassertions/Src/FluentAssertions/NumericAssertionsExtensions.cs

Line 668 in fb53da1

public static AndConstraint<NullableNumericAssertions<float>> BeApproximately(this NullableNumericAssertions<float> parent,