Raise Error Question

Ruby
1

Attached are two files that are an RPN calculator and its accompanying
rspec tests, respectively.

I am having an issue with passing the test:

“it “fails informatively when there’s not enough values stacked away” do
expect {
calculator.plus
}.to raise_error(“calculator is empty”)”

and am having this failure:

"Failures:

  1. RPNCalculator fails informatively when there’s not enough values
    stacked away
    Failure/Error: expect {
    expected Exception with “calculator is empty” but nothing was
    raised

    ./12_rpn_calculator/rpn_calculator_spec.rb:117:in `block (2

levels) in <top (required)>’"

Relevant code for this is as follows:

"class RPNCalculator
def initialize(value = 0, array = [])
@value = value
@array = array
end

def value
return @value
end

def push(num)
@array << num
end

def plus
if @array.length >= 2
@value += @array[-1] + @array[-2]
@array.pop(2)
elsif @array.length == 1
@value += @array[-1]
@array.pop
else
raise “calculator is empty”
end
end
end"

Any help will be appreciated, thanks.