using System;

using FluentAssertions;

​

double temp1 = 0.1 - 0.025;

double temp2 = 0.075;

((object)temp1).Should().BeEquivalentTo(temp2, options => options.Using<double>(a => a.Subject.HasMinimalDifference(a.Expectation, 1)).WhenTypeIs<double>());

Console.WriteLine("passed\n-----");

((object)temp1).Should().BeEquivalentTo(10, options => options.Using<double>(a => a.Subject.HasMinimalDifference(a.Expectation, 1)).WhenTypeIs<double>());

public static class DoubleExts

{

    public static bool HasMinimalDifference(this double value1, double value2, int units)

    {

        long lValue1 = BitConverter.DoubleToInt64Bits(value1);

        long lValue2 = BitConverter.DoubleToInt64Bits(value2);

        // If the signs are different, return false except for +0 and -0.

        if ((lValue1 >> 63) != (lValue2 >> 63))

        {

            if (value1 == value2)

                return true;

            return false;

        }

​

        long diff = Math.Abs(lValue1 - lValue2);

        if (diff <= (long)units)

            return true;

        return false;

    }

}