`class BeWithin`

Represents a predicate that checks if the subject is within a tolerance of a value.

Nested

Bounded

Definitions

`def initialize(tolerance)`

Initialize a new BeWithin predicate.

Signature

parameter　tolerance　Numeric: The tolerance value.

Implementation

def initialize(tolerance)
	@tolerance = tolerance
end

`def of(value)`

Create a bounded predicate that checks if the subject is within tolerance of a value.

Signature

parameter　value　Numeric: The value to check against.
returns　Bounded: A new Bounded predicate.

Implementation

def of(value)
	tolerance = @tolerance.abs
	
	return Bounded.new(Range.new(value - tolerance, value + tolerance))
end

`def percent_of(value)`

Create a bounded predicate that checks if the subject is within a percentage tolerance of a value.

Signature

parameter　value　Numeric: The value to check against.
returns　Bounded: A new Bounded predicate.

Implementation

def percent_of(value)
	tolerance = Rational(@tolerance, 100)
	
	return Bounded.new(Range.new(value - value * tolerance, value + value * tolerance))
end

`def print(output)`

Print a representation of this predicate.

Signature

parameter　output　Output: The output target.

Implementation

def print(output)
	output.write("be within ", :variable, @tolerance, :reset)
end

`def call(assertions, subject)`

Evaluate this predicate against a subject.

Signature

parameter　assertions　Assertions: The assertions instance to use.
parameter　subject　Object: The subject to evaluate.

Implementation

def call(assertions, subject)
	assertions.nested(self) do |assertions|
		assertions.assert(subject < @tolerance, self)
	end
end