Add test template for perfect-numbers

exercises/practice/perfect-numbers/.meta/config.json

@@ -10,7 +10,8 @@
     "iHiD",
     "Insti",
     "kotp",
-    "tryantwit"
+    "tryantwit",
+    "themetar"
   ],
   "files": {
     "solution": [

exercises/practice/perfect-numbers/.meta/example.rb

@@ -1,24 +1,25 @@
-class PerfectNumber
-  def self.classify(num)
-    raise 'not a natural number' if num < 0
-    aliquot_sum = aliquot_sum(num)
-    aliquot_sum == num ? "perfect" : aliquot_sum < num ? "deficient" : 'abundant'
-  end
+module PerfectNumber
+  def self.classify(number)
+    raise ArgumentError, 'Classification is only possible for positive integers.' unless number > 0
+
+    aliquot_sum = get_divisors(number).sum
 
-  def self.aliquot_sum(num)
-    get_divisors(num).reduce(:+)
+    if aliquot_sum == number
+      "perfect"
+    else
+      aliquot_sum < number ? "deficient" : 'abundant'
+    end
   end
 
-  private
+  def self.get_divisors(number)
+    return [] if number == 1
+
+    (2..Math.sqrt(number)).each_with_object [1] do |n, divisors|
+      div, mod = number.divmod n
+      next unless mod.zero?
 
-  def self.get_divisors(num)
-    divisors = [0]
-    (1..Math.sqrt(num)).each do |n|
-      if num % n == 0
-        divisors << n
-        divisors << num/n unless (n == 1) || (num/n) == n
-      end
+      divisors << n
+      divisors << div unless div == n
     end
-    divisors
   end
 end

exercises/practice/perfect-numbers/.meta/test_template.erb

@@ -0,0 +1,18 @@
+require 'minitest/autorun'
+require_relative 'perfect_numbers'
+
+class PerfectNumberTest < Minitest::Test
+<% json["cases"].each do |group| %>
+  <% group["cases"].each do |sub_case| %>
+    def test_<%= underscore(sub_case["description"]) %>
+      <%= skip? %> 
+      <%- if sub_case["expected"].is_a?(Hash) && sub_case["expected"].key?("error") -%>
+        error = assert_raises(ArgumentError) { PerfectNumber.<%= underscore(sub_case["property"]) %>(<%= sub_case["input"]["number"] %>) }
+        assert_equal '<%= sub_case["expected"]["error"] %>', error.message
+      <%- else -%>
+        assert_equal '<%= sub_case["expected"] %>', PerfectNumber.<%= underscore(sub_case["property"]) %>(<%= sub_case["input"]["number"] %>)
+      <%- end -%>
+    end
+  <% end %>
+<% end %>
+end

exercises/practice/perfect-numbers/perfect_numbers_test.rb

@@ -2,21 +2,70 @@
 require_relative 'perfect_numbers'
 
 class PerfectNumberTest < Minitest::Test
-  def test_initialize_perfect_number
-    assert_raises RuntimeError do
-      PerfectNumber.classify(-1)
-    end
+  def test_smallest_perfect_number_is_classified_correctly
+    # skip
+    assert_equal 'perfect', PerfectNumber.classify(6)
   end
 
-  def test_classify_deficient
-    assert_equal 'deficient', PerfectNumber.classify(13)
+  def test_medium_perfect_number_is_classified_correctly
+    skip
+    assert_equal 'perfect', PerfectNumber.classify(28)
   end
 
-  def test_classify_perfect
-    assert_equal 'perfect', PerfectNumber.classify(28)
+  def test_large_perfect_number_is_classified_correctly
+    skip
+    assert_equal 'perfect', PerfectNumber.classify(33_550_336)
   end
 
-  def test_classify_abundant
+  def test_smallest_abundant_number_is_classified_correctly
+    skip
     assert_equal 'abundant', PerfectNumber.classify(12)
   end
+
+  def test_medium_abundant_number_is_classified_correctly
+    skip
+    assert_equal 'abundant', PerfectNumber.classify(30)
+  end
+
+  def test_large_abundant_number_is_classified_correctly
+    skip
+    assert_equal 'abundant', PerfectNumber.classify(33_550_335)
+  end
+
+  def test_smallest_prime_deficient_number_is_classified_correctly
+    skip
+    assert_equal 'deficient', PerfectNumber.classify(2)
+  end
+
+  def test_smallest_non_prime_deficient_number_is_classified_correctly
+    skip
+    assert_equal 'deficient', PerfectNumber.classify(4)
+  end
+
+  def test_medium_deficient_number_is_classified_correctly
+    skip
+    assert_equal 'deficient', PerfectNumber.classify(32)
+  end
+
+  def test_large_deficient_number_is_classified_correctly
+    skip
+    assert_equal 'deficient', PerfectNumber.classify(33_550_337)
+  end
+
+  def test_edge_case_no_factors_other_than_itself_is_classified_correctly
+    skip
+    assert_equal 'deficient', PerfectNumber.classify(1)
+  end
+
+  def test_zero_is_rejected_as_it_is_not_a_positive_integer
+    skip
+    error = assert_raises(ArgumentError) { PerfectNumber.classify(0) }
+    assert_equal 'Classification is only possible for positive integers.', error.message
+  end
+
+  def test_negative_integer_is_rejected_as_it_is_not_a_positive_integer
+    skip
+    error = assert_raises(ArgumentError) { PerfectNumber.classify(-1) }
+    assert_equal 'Classification is only possible for positive integers.', error.message
+  end
 end