Failed to define a simple unit test testcase

Question

I am trying to do a simple test case with Test Unit, in Ruby 1.9.1 (Ubuntu Linux 12.04 64 bits) : but it says me that the initialize method of my TestCase is missing arguments. And when I look further at the error, it says me that it tried to launch /usr/lib/ruby/1.9.1/minitest.

However, I installed the Test Unit gem before.

This is the first source file : Run.rb

#!/usr/bin/env ruby

require "test/unit"
require_relative "NumbersSet.rb"

def draw_result
    the_drawn_result = nil
    loop do
        the_drawn_result = rand(1000)
        break if the_drawn_result >= 100
    end
    the_drawn_result
end

def do_operation(operation, number_1, number_2)
    return nil if number_1 < 1 or number_2 < 1
    number_1, number_2 = number_2, number_1 if  number_1 < number_2
    case operation
        when :add
            result = number_1 + number_2
            return "#{number_1} + #{number_2} = #{result}", result
        when :sub
            return nil if number_1 == number_2 # A zero result will not help us
            result = number_1 - number_2
            return "#{number_1} - #{number_2} = #{result}", result
        when :mul
            return nil if number_1 == 1 or number_2 == 1 # Otherwise, this would be identity operation
            result = number_1 * number_2
            return "#{number_1} * #{number_2} = #{result}", result
        when :div
            return nil if number_1 == 1 or number_2 == 1 # Otherwise, this could be identity operation
            return nil if number_1 % number_2 != 0
            result = number_1 / number_2
            return "#{number_1} / #{number_2} = #{result}", result
        else
            raise "Unknown operation #{operation} !"
    end
end

def play
    drawn_numbers = NumbersSet.draw
    puts drawn_numbers.inspect, draw_result
end

class DrawTest < Test::Unit::TestCase
    def draw_test

        assert_equal(nil, do_operation(:add, -3, 1))
        assert_equal(nil, do_operation(:add, 1, -1))
        assert_equal(nil, do_operation(:add, 5, 0))
        assert_equal(nil, do_operation(:add, 0, 5))
        assert_equal(nil, do_operation(:add, 3, 5))
        assert_equal(nil, do_operation(:add, 5, 3))

        assert_equal(nil, do_operation(:sub, 5, 3))
        assert_equal(nil, do_operation(:sub, 3, 5))
        assert_equal(nil, do_operation(:sub, 3, 3))

        assert_equal(nil, do_operation(:mul, 3, 5))
        assert_equal(nil, do_operation(:mul, 5, 3))
        assert_equal(nil, do_operation(:mul, 3, 1))
        assert_equal(nil, do_operation(:mul, 1, 3))

        assert_equal(nil, do_operation(:div, 20, 3))
        assert_equal(nil, do_operation(:div, 3, 20))
        assert_equal(nil, do_operation(:div, 20, 1))
        assert_equal(nil, do_operation(:div, 1, 20))
        assert_equal(nil, do_operation(:div, 20, 4))
        assert_equal(nil, do_operation(:div, 5, 20))

    end
end

OPERATIONS = [:add, :sub, :mul, :div]

DrawTest.new.draw_test

This is the second file : NumbersSet.rb

class NumbersSet

    def self.draw
        plaques = {}
        (1..10).each { |value| plaques[value] = 2}
        [25,50,75,100].each { |value| plaques[value] = 1}

        draw_possibilities = (1..10).to_a << 25 << 50 << 75 << 100
        the_draw = []
        6.times do |loop_index|
            drawn_number_index = nil
            loop do
                drawn_number_index = rand(draw_possibilities.size)
                break if plaques[draw_possibilities[drawn_number_index]] > 0
            end
            the_draw << draw_possibilities[drawn_number_index]
            plaques[draw_possibilities[drawn_number_index]] -= 1
        end
        the_draw
    end

end

And this this the terminal error :

$ ./Run.rb 
/usr/lib/ruby/1.9.1/minitest/unit.rb:971:in `initialize': wrong number of arguments (0 for 1) (ArgumentError)
    from ./Run.rb:77:in `new'
    from ./Run.rb:77:in `<main>'

So, is this really a bad coding from myself, or an installation issue ? Thanks in advance.

Answer 1

I found what went bad :

In file Run.rb, where I defined my TestCase subclass :

1. The DrawTest class, as a subclass of Test::Unit::TestCase must define its tests methods with a name that begins with test => So was not draw_test.
2. I must not create an instance of DrawTest class, as I did in the previous version

So this source file is better :

#!/usr/bin/env ruby

require "test/unit"
require_relative "NumbersSet.rb"

def draw_result
    the_drawn_result = nil
    loop do
        the_drawn_result = rand(1000)
        break if the_drawn_result >= 100
    end
    the_drawn_result
end

def do_operation(operation, number_1, number_2)
    return nil if number_1 < 1 or number_2 < 1
    number_1, number_2 = number_2, number_1 if  number_1 < number_2
    case operation
        when :add
            result = number_1 + number_2
            return "#{number_1} + #{number_2} = #{result}", result
        when :sub
            return nil if number_1 == number_2 # A zero result will not help us
            result = number_1 - number_2
            return "#{number_1} - #{number_2} = #{result}", result
        when :mul
            return nil if number_1 == 1 or number_2 == 1 # Otherwise, this would be identity operation
            result = number_1 * number_2
            return "#{number_1} * #{number_2} = #{result}", result
        when :div
            return nil if number_1 == 1 or number_2 == 1 # Otherwise, this could be identity operation
            return nil if number_1 % number_2 != 0
            result = number_1 / number_2
            return "#{number_1} / #{number_2} = #{result}", result
        else
            raise "Unknown operation #{operation} !"
    end
end

def play
    drawn_numbers = NumbersSet.draw
    puts drawn_numbers.inspect, draw_result
end

class DrawTest < Test::Unit::TestCase
    def test_draw

        assert_equal(nil, do_operation(:add, -3, 1))
        assert_equal(nil, do_operation(:add, 1, -1))
        assert_equal(nil, do_operation(:add, 5, 0))
        assert_equal(nil, do_operation(:add, 0, 5))

        assert_equal(nil, do_operation(:sub, -3, 1))
        assert_equal(nil, do_operation(:sub, 1, -1))
        assert_equal(nil, do_operation(:sub, 5, 0))
        assert_equal(nil, do_operation(:sub, 0, 5))

        assert_equal(nil, do_operation(:mul, -3, 1))
        assert_equal(nil, do_operation(:mul, 1, -1))
        assert_equal(nil, do_operation(:mul, 5, 0))
        assert_equal(nil, do_operation(:mul, 0, 5))

        assert_equal(nil, do_operation(:div, -3, 1))
        assert_equal(nil, do_operation(:div, 1, -1))
        assert_equal(nil, do_operation(:div, 5, 0))
        assert_equal(nil, do_operation(:div, 0, 5))

        assert_equal(nil, do_operation(:add, 3, 5))
        assert_equal(nil, do_operation(:add, 5, 3))

        assert_equal(nil, do_operation(:sub, 5, 3))
        assert_equal(nil, do_operation(:sub, 3, 5))
        assert_equal(nil, do_operation(:sub, 3, 3))

        assert_equal(nil, do_operation(:mul, 3, 5))
        assert_equal(nil, do_operation(:mul, 5, 3))
        assert_equal(nil, do_operation(:mul, 3, 1))
        assert_equal(nil, do_operation(:mul, 1, 3))

        assert_equal(nil, do_operation(:div, 20, 3))
        assert_equal(nil, do_operation(:div, 3, 20))
        assert_equal(nil, do_operation(:div, 20, 1))
        assert_equal(nil, do_operation(:div, 1, 20))
        assert_equal(nil, do_operation(:div, 20, 4))
        assert_equal(nil, do_operation(:div, 5, 20))

    end
end

OPERATIONS = [:add, :sub, :mul, :div]