BUG OF THE MONTH | Expression is always true

public virtual DateTime NextDate(....)
{
  ....
  // both are valid dates, so chose one randomly
  if (   IsWithinRange(nextDayOfWeek, minDateTime, maxDateTime) 
      && IsWithinRange(previousDayOfWeek, minDateTime, maxDateTime))
  {
    return _random.Next(0, 1) == 0  
           ? previousDayOfWeek
           : nextDayOfWeek;
  }
  ....
}

V3022 Expression ‘_random.Next(0, 1) == 0’ is always true. RandomValueGenerator.cs 142

The bottom line was that either one or the other value was selected with a 50% probability. However, in this case, the Next method will always return 0.

This happens because the second argument is not included in the range of values. That is, the value that the method can return will be in the range [0,1). Let’s fix that:

public virtual DateTime NextDate(....)
{
  ....
  // both are valid dates, so chose one randomly
  if (   IsWithinRange(nextDayOfWeek, minDateTime, maxDateTime) 
      && IsWithinRange(previousDayOfWeek, minDateTime, maxDateTime))
  {
    return _random.Next(0, 2) == 0
           ? previousDayOfWeek
           : nextDayOfWeek;
  }
  ....
}

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