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Intro to TDD
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class Calculator | |
attr_reader :string_to_calculate | |
def initialize(string_to_calculate, options = {}) | |
@string_to_calculate = string_to_calculate | |
@delimiter = options[:delimiter] | |
end | |
def add | |
raise ArgumentError, error_message unless negatives.empty? | |
numbers.reject { |x| x > 1000 }.reduce(0, :+) | |
end | |
def self.add(string, options = {}) | |
new(string, options).add | |
end | |
private | |
def delimiter | |
@regex_delimiter ||= Regexp.new("[,\\n#{Regexp.escape(@delimiter.to_s)}]") | |
end | |
def numbers | |
@numbers ||= string_to_calculate.split(delimiter).map(&:to_i) | |
end | |
def negatives | |
@negatives ||= numbers.select { |n| n < 0 } | |
end | |
def error_message | |
"negatives are not allowed: #{negatives.join(", ")}" | |
end | |
end |
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gem 'minitest' | |
require "minitest/autorun" | |
require_relative "calculator" | |
class TestCalculator < Minitest::Test | |
def test_given_a_string_returns_a_number | |
number = rand(100) | |
assert_equal number, Calculator.add(number.to_s) | |
end | |
def test_empty_string_returns_zero | |
assert_equal 0, Calculator.add("") | |
end | |
def test_csv_should_sum_values | |
n1 = rand(100) | |
n2 = rand(100) | |
assert_equal n1 + n2, Calculator.add("#{n1},#{n2}") | |
end | |
def random_nuber_array(min, max) | |
numbers = Array.new((min..max).to_a.sample) { |x| rand(100) } | |
end | |
def test_greater_than_two_numbers_sum_values | |
assert_equal 10, Calculator.add("1,3,5,1") | |
numbers = random_nuber_array(2, 50) | |
sum = 0 | |
numbers.each { |x| sum += x } | |
assert_equal sum , Calculator.add(numbers.join(",")) | |
end | |
def test_newline_as_delimeter_when_summing_values | |
["1\n2,3", "1\n2\n3"].each do |number_string| | |
assert_equal 6, Calculator.add(number_string) | |
end | |
end | |
def test_negative_number_throws_error | |
[ | |
{ input: "-1", error: "-1" }, | |
{ input: "1,2,-5", error: "-5" }, | |
{ input: "-1,-2,-3", error: "-1, -2, -3" }, | |
{ input: "-1,22,-3", error: "-1, -3" }, | |
].each do |test| | |
err = assert_raises ArgumentError do | |
Calculator.add(test[:input]) | |
end | |
assert_equal "negatives are not allowed: " + test[:error], err.message | |
end | |
end | |
def test_ignore_numbers_greater_than_1000 | |
[ | |
{ input: "1001", sum: 0 }, | |
{ input: "1001,2", sum: 2 }, | |
{ input: "1000,2", sum: 1002 }, | |
{ input: "1002,10", sum: 10 }, | |
{ input: "5,1020,7", sum: 12 } | |
].each do |test| | |
assert_equal test[:sum], Calculator.add(test[:input]) | |
end | |
end | |
def test_user_specified_delimiter | |
["+", "|", ".", "]"].each do |delimiter| | |
assert_equal 6, Calculator.add([1, 2, 3].join(delimiter), delimiter: delimiter) | |
end | |
end | |
def test_custom_delimiter_with_default_delimiters | |
assert_equal 10, Calculator.add("1,2+3\n4", delimiter: "+") | |
end | |
end |
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