lib/Assertion.php
function closeTo($value, float $delta): self {
    return $this->expect($this->target, equalTo($value, $delta));
  }
function closeTo($value, float $delta): self {
    return $this->expect($this->target, equalTo($value, $delta));
  }
Reports an error if the target is not equal to the specified value, within a given delta range.
@param int|float $value The value to compare.
@param float $delta The allowed distance between two values to consider them equal.
@return self This instance.