From 6d26886323c3416d7fae142b15638ce5857896d3 Mon Sep 17 00:00:00 2001
From: meatball <meatballsofmeatballs@gmail.com>
Date: Sun, 31 Aug 2025 17:39:44 +0200
Subject: [PATCH 1/6] Add templates for exercises batch 3

---
 .../circular-buffer/.meta/test_template.erb   |  30 ++++
 .../circular-buffer/circular_buffer_test.rb   | 138 ++++++++++--------
 .../crypto-square/.meta/test_template.erb     |  12 ++
 .../practice/crypto-square/.meta/tests.toml   |   5 +
 .../crypto-square/crypto_square_test.rb       |  34 ++---
 .../custom-set/.meta/test_template.erb        |  43 ++++++
 .../practice/custom-set/custom_set_test.rb    |  25 +++-
 .../practice/darts/.meta/test_template.erb    |  12 ++
 exercises/practice/darts/darts_test.rb        |   4 +-
 .../practice/diamond/.meta/test_template.erb  |  15 ++
 exercises/practice/diamond/diamond_test.rb    | 107 +++++++++++---
 .../.meta/test_template.erb                   |  13 ++
 .../dnd-character/.meta/test_template.erb     |  69 +++++++++
 .../dnd-character/dnd_character_test.rb       |  50 +++----
 14 files changed, 433 insertions(+), 124 deletions(-)
 create mode 100644 exercises/practice/circular-buffer/.meta/test_template.erb
 create mode 100644 exercises/practice/crypto-square/.meta/test_template.erb
 create mode 100644 exercises/practice/custom-set/.meta/test_template.erb
 create mode 100644 exercises/practice/darts/.meta/test_template.erb
 create mode 100644 exercises/practice/diamond/.meta/test_template.erb
 create mode 100644 exercises/practice/difference-of-squares/.meta/test_template.erb
 create mode 100644 exercises/practice/dnd-character/.meta/test_template.erb

diff --git a/exercises/practice/circular-buffer/.meta/test_template.erb b/exercises/practice/circular-buffer/.meta/test_template.erb
new file mode 100644
index 0000000000..3be26a5f29
--- /dev/null
+++ b/exercises/practice/circular-buffer/.meta/test_template.erb
@@ -0,0 +1,30 @@
+require 'minitest/autorun'
+require_relative 'circular_buffer'
+
+class CircularBufferTest < Minitest::Test
+<% json["cases"].each do |cases| %>
+    def test_<%= underscore(cases["description"]) %>
+        <%= skip? %> 
+        buffer = CircularBuffer.new(<%= cases["input"]["capacity"] %>)
+        <%- cases["input"]["operations"].each do |operation| -%>
+            <%- if operation["operation"] == "read"-%>
+                <%- if operation["should_succeed"] -%>
+                    assert_equal '<%= operation["expected"] %>', buffer.read
+                <%- else -%>
+                    assert_raises(CircularBuffer::BufferEmptyException) { buffer.read }
+                <%- end -%>
+            <%- elsif operation["operation"] == "write" -%>
+                <%- if operation["should_succeed"] -%>
+                    buffer.write('<%= operation["item"] %>')
+                <%- else -%>
+                    assert_raises(CircularBuffer::BufferFullException) { buffer.write('<%= operation["item"] %>') }
+                <%- end -%>
+            <%- elsif operation["operation"] == "overwrite" -%>
+                buffer.write!('<%= operation["item"] %>')
+            <% elsif operation["operation"] == "clear" -%>
+                buffer.clear
+            <%- end -%>
+        <%- end -%>
+    end
+    <% end %>
+end
\ No newline at end of file
diff --git a/exercises/practice/circular-buffer/circular_buffer_test.rb b/exercises/practice/circular-buffer/circular_buffer_test.rb
index c239e444e4..eacd0f54d0 100644
--- a/exercises/practice/circular-buffer/circular_buffer_test.rb
+++ b/exercises/practice/circular-buffer/circular_buffer_test.rb
@@ -2,107 +2,131 @@
 require_relative 'circular_buffer'
 
 class CircularBufferTest < Minitest::Test
-  def test_read_empty_buffer_throws_buffer_empty_exception
+  def test_reading_empty_buffer_should_fail
+    # skip
     buffer = CircularBuffer.new(1)
     assert_raises(CircularBuffer::BufferEmptyException) { buffer.read }
   end
 
-  def test_write_and_read_back_one_item
+  def test_can_read_an_item_just_written
     skip
     buffer = CircularBuffer.new(1)
-    buffer.write '1'
+    buffer.write('1')
     assert_equal '1', buffer.read
-    assert_raises(CircularBuffer::BufferEmptyException) { buffer.read }
   end
 
-  def test_write_and_read_back_multiple_items
+  def test_each_item_may_only_be_read_once
     skip
-    buffer = CircularBuffer.new(2)
-    buffer.write '1'
-    buffer.write '2'
+    buffer = CircularBuffer.new(1)
+    buffer.write('1')
     assert_equal '1', buffer.read
-    assert_equal '2', buffer.read
     assert_raises(CircularBuffer::BufferEmptyException) { buffer.read }
   end
 
-  def test_clearing_buffer
+  def test_items_are_read_in_the_order_they_are_written
     skip
-    buffer = CircularBuffer.new(3)
-    ('1'..'3').each { |i| buffer.write i }
-    buffer.clear
-    assert_raises(CircularBuffer::BufferEmptyException) { buffer.read }
-    buffer.write '1'
-    buffer.write '2'
+    buffer = CircularBuffer.new(2)
+    buffer.write('1')
+    buffer.write('2')
     assert_equal '1', buffer.read
-    buffer.write '3'
     assert_equal '2', buffer.read
   end
 
-  def test_alternate_write_and_read
+  def test_full_buffer_cant_be_written_to
     skip
-    buffer = CircularBuffer.new(2)
-    buffer.write '1'
+    buffer = CircularBuffer.new(1)
+    buffer.write('1')
+    assert_raises(CircularBuffer::BufferFullException) { buffer.write('2') }
+  end
+
+  def test_a_read_frees_up_capacity_for_another_write
+    skip
+    buffer = CircularBuffer.new(1)
+    buffer.write('1')
     assert_equal '1', buffer.read
-    buffer.write '2'
+    buffer.write('2')
     assert_equal '2', buffer.read
   end
 
-  def test_reads_back_oldest_item
+  def test_read_position_is_maintained_even_across_multiple_writes
     skip
     buffer = CircularBuffer.new(3)
-    buffer.write '1'
-    buffer.write '2'
-    buffer.read
-    buffer.write '3'
+    buffer.write('1')
+    buffer.write('2')
+    assert_equal '1', buffer.read
+    buffer.write('3')
     assert_equal '2', buffer.read
     assert_equal '3', buffer.read
   end
 
-  def test_writing_to_a_full_buffer_throws_an_exception
+  def test_items_cleared_out_of_buffer_cant_be_read
     skip
-    buffer = CircularBuffer.new(2)
-    buffer.write '1'
-    buffer.write '2'
-    assert_raises(CircularBuffer::BufferFullException) { buffer.write 'A' }
+    buffer = CircularBuffer.new(1)
+    buffer.write('1')
+    buffer.clear
+    assert_raises(CircularBuffer::BufferEmptyException) { buffer.read }
   end
 
-  def test_overwriting_oldest_item_in_a_full_buffer
+  def test_clear_frees_up_capacity_for_another_write
     skip
-    buffer = CircularBuffer.new(2)
-    buffer.write '1'
-    buffer.write '2'
-    buffer.write! 'A'
+    buffer = CircularBuffer.new(1)
+    buffer.write('1')
+    buffer.clear
+    buffer.write('2')
     assert_equal '2', buffer.read
-    assert_equal 'A', buffer.read
-    assert_raises(CircularBuffer::BufferEmptyException) { buffer.read }
   end
 
-  def test_forced_writes_to_non_full_buffer_should_behave_like_writes
+  def test_clear_does_nothing_on_empty_buffer
+    skip
+    buffer = CircularBuffer.new(1)
+    buffer.clear
+    buffer.write('1')
+    assert_equal '1', buffer.read
+  end
+
+  def test_overwrite_acts_like_write_on_non_full_buffer
     skip
     buffer = CircularBuffer.new(2)
-    buffer.write '1'
-    buffer.write! '2'
+    buffer.write('1')
+    buffer.write!('2')
     assert_equal '1', buffer.read
     assert_equal '2', buffer.read
-    assert_raises(CircularBuffer::BufferEmptyException) { buffer.read }
   end
 
-  def test_alternate_read_and_write_into_buffer_overflow
+  def test_overwrite_replaces_the_oldest_item_on_full_buffer
+    skip
+    buffer = CircularBuffer.new(2)
+    buffer.write('1')
+    buffer.write('2')
+    buffer.write!('3')
+    assert_equal '2', buffer.read
+    assert_equal '3', buffer.read
+  end
+
+  def test_overwrite_replaces_the_oldest_item_remaining_in_buffer_following_a_read
     skip
-    buffer = CircularBuffer.new(5)
-    ('1'..'3').each { |i| buffer.write i }
-    buffer.read
-    buffer.read
-    buffer.write '4'
-    buffer.read
-    ('5'..'8').each { |i| buffer.write i }
-    buffer.write! 'A'
-    buffer.write! 'B'
-    ('6'..'8').each do |i|
-      assert_equal i, buffer.read
-    end
-    assert_equal 'A', buffer.read
-    assert_equal 'B', buffer.read
+    buffer = CircularBuffer.new(3)
+    buffer.write('1')
+    buffer.write('2')
+    buffer.write('3')
+    assert_equal '1', buffer.read
+    buffer.write('4')
+    buffer.write!('5')
+    assert_equal '3', buffer.read
+    assert_equal '4', buffer.read
+    assert_equal '5', buffer.read
+  end
+
+  def test_initial_clear_does_not_affect_wrapping_around
+    skip
+    buffer = CircularBuffer.new(2)
+    buffer.clear
+    buffer.write('1')
+    buffer.write('2')
+    buffer.write!('3')
+    buffer.write!('4')
+    assert_equal '3', buffer.read
+    assert_equal '4', buffer.read
     assert_raises(CircularBuffer::BufferEmptyException) { buffer.read }
   end
 end
diff --git a/exercises/practice/crypto-square/.meta/test_template.erb b/exercises/practice/crypto-square/.meta/test_template.erb
new file mode 100644
index 0000000000..7ab2747dbd
--- /dev/null
+++ b/exercises/practice/crypto-square/.meta/test_template.erb
@@ -0,0 +1,12 @@
+require 'minitest/autorun'
+require_relative 'crypto_square'
+
+class CryptoSquareTest < Minitest::Test
+<% json["cases"].each do |cases| %>
+    def test_<%= underscore(cases["description"]) %>
+        <%= skip? %> 
+        plaintext = '<%= cases["input"]["plaintext"] %>'
+        assert_equal '<%= cases["expected"] %>', Crypto.new(plaintext).ciphertext
+    end
+    <% end %>
+end
\ No newline at end of file
diff --git a/exercises/practice/crypto-square/.meta/tests.toml b/exercises/practice/crypto-square/.meta/tests.toml
index 085d142ead..94ef0819fe 100644
--- a/exercises/practice/crypto-square/.meta/tests.toml
+++ b/exercises/practice/crypto-square/.meta/tests.toml
@@ -32,3 +32,8 @@ description = "8 character plaintext results in 3 chunks, the last one with a tr
 
 [fbcb0c6d-4c39-4a31-83f6-c473baa6af80]
 description = "54 character plaintext results in 7 chunks, the last two with trailing spaces"
+include = false
+
+[33fd914e-fa44-445b-8f38-ff8fbc9fe6e6]
+description = "54 character plaintext results in 8 chunks, the last two with trailing spaces"
+reimplements = "fbcb0c6d-4c39-4a31-83f6-c473baa6af80"
diff --git a/exercises/practice/crypto-square/crypto_square_test.rb b/exercises/practice/crypto-square/crypto_square_test.rb
index 2802501ea8..d7b88e141e 100644
--- a/exercises/practice/crypto-square/crypto_square_test.rb
+++ b/exercises/practice/crypto-square/crypto_square_test.rb
@@ -4,49 +4,49 @@
 class CryptoSquareTest < Minitest::Test
   def test_empty_plaintext_results_in_an_empty_ciphertext
     # skip
-    plaintext = ""
-    assert_equal "", Crypto.new(plaintext).ciphertext
+    plaintext = ''
+    assert_equal '', Crypto.new(plaintext).ciphertext
   end
 
   def test_normalization_results_in_empty_plaintext
     skip
-    plaintext = "... --- ..."
-    assert_equal "", Crypto.new(plaintext).ciphertext
+    plaintext = '... --- ...'
+    assert_equal '', Crypto.new(plaintext).ciphertext
   end
 
   def test_lowercase
     skip
-    plaintext = "A"
-    assert_equal "a", Crypto.new(plaintext).ciphertext
+    plaintext = 'A'
+    assert_equal 'a', Crypto.new(plaintext).ciphertext
   end
 
   def test_remove_spaces
     skip
-    plaintext = "  b "
-    assert_equal "b", Crypto.new(plaintext).ciphertext
+    plaintext = '  b '
+    assert_equal 'b', Crypto.new(plaintext).ciphertext
   end
 
   def test_remove_punctuation
     skip
-    plaintext = "@1,%!"
-    assert_equal "1", Crypto.new(plaintext).ciphertext
+    plaintext = '@1,%!'
+    assert_equal '1', Crypto.new(plaintext).ciphertext
   end
 
   def test_9_character_plaintext_results_in_3_chunks_of_3_characters
     skip
-    plaintext = "This is fun!"
-    assert_equal "tsf hiu isn", Crypto.new(plaintext).ciphertext
+    plaintext = 'This is fun!'
+    assert_equal 'tsf hiu isn', Crypto.new(plaintext).ciphertext
   end
 
   def test_8_character_plaintext_results_in_3_chunks_the_last_one_with_a_trailing_space
     skip
-    plaintext = "Chill out."
-    assert_equal "clu hlt io ", Crypto.new(plaintext).ciphertext
+    plaintext = 'Chill out.'
+    assert_equal 'clu hlt io ', Crypto.new(plaintext).ciphertext
   end
 
-  def test_54_character_plaintext_results_in_7_chunks_the_last_two_with_trailing_spaces
+  def test_54_character_plaintext_results_in_8_chunks_the_last_two_with_trailing_spaces
     skip
-    plaintext = "If man was meant to stay on the ground, god would have given us roots."
-    assert_equal "imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn  sseoau ", Crypto.new(plaintext).ciphertext
+    plaintext = 'If man was meant to stay on the ground, god would have given us roots.'
+    assert_equal 'imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn  sseoau ', Crypto.new(plaintext).ciphertext
   end
 end
diff --git a/exercises/practice/custom-set/.meta/test_template.erb b/exercises/practice/custom-set/.meta/test_template.erb
new file mode 100644
index 0000000000..872eb2f016
--- /dev/null
+++ b/exercises/practice/custom-set/.meta/test_template.erb
@@ -0,0 +1,43 @@
+require 'minitest/autorun'
+require_relative 'custom_set'
+
+class CustomSetTest < Minitest::Test
+<% json["cases"].each do |cases| %>
+    <% cases["cases"].each do |sub_case| %>
+        def test_<%= underscore(sub_case["description"]) %>
+            <%= skip? %>
+            <%- if sub_case["input"].key?("set") -%>
+                set = CustomSet.new <%= sub_case["input"]["set"] %>
+                <%- if sub_case["property"] == "empty" -%>
+                    <%= sub_case["expected"] ? "assert" : "refute" %>_empty set
+                <%- elsif sub_case["property"] == "contains" -%>
+                    element = <%= sub_case["input"]["element"] %>
+                    <%= sub_case["expected"] ? "assert" : "refute" %> set.member? element
+                <%- elsif sub_case["property"] == "add" -%>
+                    expected = CustomSet.new <%= sub_case["expected"] %>
+                    assert_equal expected, set.add(<%= sub_case["input"]["element"] %>)
+                <%- end -%>
+            <%- else -%>
+                set1 = CustomSet.new <%= sub_case["input"]["set1"] %>
+                set2 = CustomSet.new <%= sub_case["input"]["set2"] %>
+                <%- if sub_case["property"] == "subset" -%>
+                    <%= sub_case["expected"] ? "assert" : "refute" %> set1.subset? set2
+                <%- elsif sub_case["property"] == "disjoint" -%>
+                    <%= sub_case["expected"] ? "assert" : "refute" %> set1.disjoint? set2
+                <%- elsif sub_case["property"] == "equal" -%>
+                    <%= sub_case["expected"] ? "assert" : "refute" %>_equal set1, set2
+                <%- elsif sub_case["property"] == "intersection" -%>
+                    expected = CustomSet.new <%= sub_case["expected"] %>
+                    assert_equal expected, set1.intersection(set2)
+                <%- elsif sub_case["property"] == "difference" -%>
+                    expected = CustomSet.new <%= sub_case["expected"] %>
+                    assert_equal expected, set1.difference(set2)
+                <%- elsif sub_case["property"] == "union" -%>
+                    expected = CustomSet.new <%= sub_case["expected"] %>
+                    assert_equal expected, set1.union(set2)
+                <%- end -%>
+            <% end %>
+        end
+    <% end %>
+<% end %>
+end
\ No newline at end of file
diff --git a/exercises/practice/custom-set/custom_set_test.rb b/exercises/practice/custom-set/custom_set_test.rb
index 648fa8549c..4991e94a2e 100644
--- a/exercises/practice/custom-set/custom_set_test.rb
+++ b/exercises/practice/custom-set/custom_set_test.rb
@@ -154,6 +154,13 @@ def test_set_is_not_equal_to_larger_set_with_same_elements
     refute_equal set1, set2
   end
 
+  def test_set_is_equal_to_a_set_constructed_from_an_array_with_duplicates
+    skip
+    set1 = CustomSet.new [1]
+    set2 = CustomSet.new [1, 1]
+    assert_equal set1, set2
+  end
+
   def test_add_to_empty_set
     skip
     set = CustomSet.new []
@@ -180,7 +187,7 @@ def test_intersection_of_two_empty_sets_is_an_empty_set
     set1 = CustomSet.new []
     set2 = CustomSet.new []
     expected = CustomSet.new []
-    assert_equal expected, set2.intersection(set1)
+    assert_equal expected, set1.intersection(set2)
   end
 
   def test_intersection_of_an_empty_set_and_non_empty_set_is_an_empty_set
@@ -188,7 +195,7 @@ def test_intersection_of_an_empty_set_and_non_empty_set_is_an_empty_set
     set1 = CustomSet.new []
     set2 = CustomSet.new [3, 2, 5]
     expected = CustomSet.new []
-    assert_equal expected, set2.intersection(set1)
+    assert_equal expected, set1.intersection(set2)
   end
 
   def test_intersection_of_a_non_empty_set_and_an_empty_set_is_an_empty_set
@@ -196,7 +203,7 @@ def test_intersection_of_a_non_empty_set_and_an_empty_set_is_an_empty_set
     set1 = CustomSet.new [1, 2, 3, 4]
     set2 = CustomSet.new []
     expected = CustomSet.new []
-    assert_equal expected, set2.intersection(set1)
+    assert_equal expected, set1.intersection(set2)
   end
 
   def test_intersection_of_two_sets_with_no_shared_elements_is_an_empty_set
@@ -204,7 +211,7 @@ def test_intersection_of_two_sets_with_no_shared_elements_is_an_empty_set
     set1 = CustomSet.new [1, 2, 3]
     set2 = CustomSet.new [4, 5, 6]
     expected = CustomSet.new []
-    assert_equal expected, set2.intersection(set1)
+    assert_equal expected, set1.intersection(set2)
   end
 
   def test_intersection_of_two_sets_with_shared_elements_is_a_set_of_the_shared_elements
@@ -212,7 +219,7 @@ def test_intersection_of_two_sets_with_shared_elements_is_a_set_of_the_shared_el
     set1 = CustomSet.new [1, 2, 3, 4]
     set2 = CustomSet.new [3, 2, 5]
     expected = CustomSet.new [2, 3]
-    assert_equal expected, set2.intersection(set1)
+    assert_equal expected, set1.intersection(set2)
   end
 
   def test_difference_of_two_empty_sets_is_an_empty_set
@@ -247,6 +254,14 @@ def test_difference_of_two_non_empty_sets_is_a_set_of_elements_that_are_only_in_
     assert_equal expected, set1.difference(set2)
   end
 
+  def test_difference_removes_all_duplicates_in_the_first_set
+    skip
+    set1 = CustomSet.new [1, 1]
+    set2 = CustomSet.new [1]
+    expected = CustomSet.new []
+    assert_equal expected, set1.difference(set2)
+  end
+
   def test_union_of_empty_sets_is_an_empty_set
     skip
     set1 = CustomSet.new []
diff --git a/exercises/practice/darts/.meta/test_template.erb b/exercises/practice/darts/.meta/test_template.erb
new file mode 100644
index 0000000000..a5ad83d9fe
--- /dev/null
+++ b/exercises/practice/darts/.meta/test_template.erb
@@ -0,0 +1,12 @@
+require 'minitest/autorun'
+require_relative 'darts'
+
+class DartsTest < Minitest::Test
+<% json["cases"].each do |cases| %>
+    def test_<%= underscore(cases["description"]) %>
+        <%= skip? %> 
+        darts = Darts.new(<%= cases["input"]["x"] %>, <%= cases["input"]["y"] %>)
+        assert_equal(<%= cases["expected"] %>, darts.score)
+    end
+    <% end %>
+end
\ No newline at end of file
diff --git a/exercises/practice/darts/darts_test.rb b/exercises/practice/darts/darts_test.rb
index d155ff2bd0..7f70119f86 100644
--- a/exercises/practice/darts/darts_test.rb
+++ b/exercises/practice/darts/darts_test.rb
@@ -26,13 +26,13 @@ def test_on_the_inner_circle
     assert_equal(10, darts.score)
   end
 
-  def test_exactly_on_centre
+  def test_exactly_on_center
     skip
     darts = Darts.new(0, 0)
     assert_equal(10, darts.score)
   end
 
-  def test_near_the_centre
+  def test_near_the_center
     skip
     darts = Darts.new(-0.1, -0.1)
     assert_equal(10, darts.score)
diff --git a/exercises/practice/diamond/.meta/test_template.erb b/exercises/practice/diamond/.meta/test_template.erb
new file mode 100644
index 0000000000..ff29ea8d18
--- /dev/null
+++ b/exercises/practice/diamond/.meta/test_template.erb
@@ -0,0 +1,15 @@
+require 'minitest/autorun'
+require_relative 'diamond'
+
+class DiamondTest < Minitest::Test
+<% json["cases"].each do |cases| %>
+    def test_<%= underscore(cases["description"]) %>
+        <%= skip? %> 
+        answer = Diamond.make_diamond('<%= cases["input"]["letter"] %>')
+        string =<% cases["expected"].each do |row| -%>
+                "<%= row %>\n"\
+        <%- end %>
+        assert_equal string, answer
+    end
+    <% end %>
+end
\ No newline at end of file
diff --git a/exercises/practice/diamond/diamond_test.rb b/exercises/practice/diamond/diamond_test.rb
index 579be07d1b..41cc04a2b2 100644
--- a/exercises/practice/diamond/diamond_test.rb
+++ b/exercises/practice/diamond/diamond_test.rb
@@ -2,34 +2,105 @@
 require_relative 'diamond'
 
 class DiamondTest < Minitest::Test
-  def test_letter_a
+  def test_degenerate_case_with_a_single_a_row
+    # skip
     answer = Diamond.make_diamond('A')
-    assert_equal "A\n", answer
+    string = "A\n"\
+
+    assert_equal string, answer
+  end
+
+  def test_degenerate_case_with_no_row_containing_3_distinct_groups_of_spaces
+    skip
+    answer = Diamond.make_diamond('B')
+    string = " A \n"\
+            "B B\n"\
+            " A \n"\
+
+    assert_equal string, answer
   end
 
-  def test_letter_c
+  def test_smallest_non_degenerate_case_with_odd_diamond_side_length
     skip
     answer = Diamond.make_diamond('C')
     string = "  A  \n"\
-             " B B \n"\
-             "C   C\n"\
-             " B B \n"\
-             "  A  \n"
+            " B B \n"\
+            "C   C\n"\
+            " B B \n"\
+            "  A  \n"\
+
     assert_equal string, answer
   end
 
-  def test_letter_e
+  def test_smallest_non_degenerate_case_with_even_diamond_side_length
     skip
-    answer = Diamond.make_diamond('E')
-    string = "    A    \n"\
-             "   B B   \n"\
-             "  C   C  \n"\
-             " D     D \n"\
-             "E       E\n"\
-             " D     D \n"\
-             "  C   C  \n"\
-             "   B B   \n"\
-             "    A    \n"
+    answer = Diamond.make_diamond('D')
+    string = "   A   \n"\
+            "  B B  \n"\
+            " C   C \n"\
+            "D     D\n"\
+            " C   C \n"\
+            "  B B  \n"\
+            "   A   \n"\
+
+    assert_equal string, answer
+  end
+
+  def test_largest_possible_diamond
+    skip
+    answer = Diamond.make_diamond('Z')
+    string = "                         A                         \n"\
+            "                        B B                        \n"\
+            "                       C   C                       \n"\
+            "                      D     D                      \n"\
+            "                     E       E                     \n"\
+            "                    F         F                    \n"\
+            "                   G           G                   \n"\
+            "                  H             H                  \n"\
+            "                 I               I                 \n"\
+            "                J                 J                \n"\
+            "               K                   K               \n"\
+            "              L                     L              \n"\
+            "             M                       M             \n"\
+            "            N                         N            \n"\
+            "           O                           O           \n"\
+            "          P                             P          \n"\
+            "         Q                               Q         \n"\
+            "        R                                 R        \n"\
+            "       S                                   S       \n"\
+            "      T                                     T      \n"\
+            "     U                                       U     \n"\
+            "    V                                         V    \n"\
+            "   W                                           W   \n"\
+            "  X                                             X  \n"\
+            " Y                                               Y \n"\
+            "Z                                                 Z\n"\
+            " Y                                               Y \n"\
+            "  X                                             X  \n"\
+            "   W                                           W   \n"\
+            "    V                                         V    \n"\
+            "     U                                       U     \n"\
+            "      T                                     T      \n"\
+            "       S                                   S       \n"\
+            "        R                                 R        \n"\
+            "         Q                               Q         \n"\
+            "          P                             P          \n"\
+            "           O                           O           \n"\
+            "            N                         N            \n"\
+            "             M                       M             \n"\
+            "              L                     L              \n"\
+            "               K                   K               \n"\
+            "                J                 J                \n"\
+            "                 I               I                 \n"\
+            "                  H             H                  \n"\
+            "                   G           G                   \n"\
+            "                    F         F                    \n"\
+            "                     E       E                     \n"\
+            "                      D     D                      \n"\
+            "                       C   C                       \n"\
+            "                        B B                        \n"\
+            "                         A                         \n"\
+
     assert_equal string, answer
   end
 end
diff --git a/exercises/practice/difference-of-squares/.meta/test_template.erb b/exercises/practice/difference-of-squares/.meta/test_template.erb
new file mode 100644
index 0000000000..85e8865cfa
--- /dev/null
+++ b/exercises/practice/difference-of-squares/.meta/test_template.erb
@@ -0,0 +1,13 @@
+require 'minitest/autorun'
+require_relative 'difference_of_squares'
+
+class DifferenceOfSquaresTest < Minitest::Test
+<% json["cases"].each do |cases| %>
+    <% cases["cases"].each do |sub_case| %>
+        def test_<%= underscore(sub_case["description"]) %>
+            <%= skip? %> 
+            assert_equal <%= sub_case["expected"] %>, Squares.new(<%= sub_case["input"]["number"] %>).<%= sub_case["property"] == "differenceOfSquares" ? "difference" : sub_case["property"].gsub(/([A-Z])/, '_\1').downcase.sub(/^_/, '') %>
+        end
+    <% end %>
+<% end %>
+end
\ No newline at end of file
diff --git a/exercises/practice/dnd-character/.meta/test_template.erb b/exercises/practice/dnd-character/.meta/test_template.erb
new file mode 100644
index 0000000000..e841b1d8de
--- /dev/null
+++ b/exercises/practice/dnd-character/.meta/test_template.erb
@@ -0,0 +1,69 @@
+require 'minitest/autorun'
+require_relative 'dnd_character'
+
+module Helpers
+  BASE_HITPOINTS = 10
+
+  def attributes
+    %i[strength dexterity constitution intelligence wisdom charisma]
+  end
+end
+
+class DndCharacterTest < Minitest::Test
+  include Helpers
+<% json["cases"].each do |cases| %>
+    <% if cases.key?("cases")%>
+
+        <% cases["cases"].each do |sub_case| %>
+            def test_<%= underscore(sub_case["description"]) %>
+                <%= skip? %>
+                <%- if sub_case["property"] == "modifier" -%>
+                assert_equal(<%= sub_case["expected"] %>, DndCharacter.modifier(<%= sub_case["input"]["score"] %>))
+                <%- end -%>
+            end
+        <% end %>
+    <% end %>
+<% end %>
+    # rubocop:disable Style/FormatString, Style/RedundantPercentQ
+  def test_random_character_stats
+    skip
+    100.times do
+      character = DndCharacter.new
+      allowed_range = (3..18)
+      expected_hitpoints = BASE_HITPOINTS +
+                           DndCharacter.modifier(character.constitution)
+      informative_message = %q(The character's %s must be within %s)
+
+      attributes.each do |attribute|
+        assert_includes allowed_range, character.send(attribute),
+          informative_message % [attribute, allowed_range]
+      end
+
+      informative_message = %q(The character's %s must be %s)
+
+      assert_equal expected_hitpoints, character.hitpoints,
+        informative_message % ['hitpoints', expected_hitpoints]
+    end
+  end
+
+  def test_stats_calculated_once
+    skip
+    informative_message = <<~EXPLAIN
+      The character's %<attribute>s must not change if called more than once.
+      It was %<first>s, is now %<second>s.
+    EXPLAIN
+
+    100.times do
+      character = DndCharacter.new
+
+      (attributes << :hitpoints).each do |attribute|
+        first = character.send(attribute)
+        second = character.send(attribute)
+
+        assert_equal first, second,
+          informative_message % { attribute:, first:, second: }
+      end
+    end
+    # rubocop:enable Style/FormatString, Style/RedundantPercentQ
+  end
+end
\ No newline at end of file
diff --git a/exercises/practice/dnd-character/dnd_character_test.rb b/exercises/practice/dnd-character/dnd_character_test.rb
index 1506f2bd6f..3667a12974 100644
--- a/exercises/practice/dnd-character/dnd_character_test.rb
+++ b/exercises/practice/dnd-character/dnd_character_test.rb
@@ -12,84 +12,84 @@ def attributes
 class DndCharacterTest < Minitest::Test
   include Helpers
 
-  def test_modifier_score_3
+  def test_ability_modifier_for_score_3_is__4
     # skip
     assert_equal(-4, DndCharacter.modifier(3))
   end
 
-  def test_modifier_score_4
+  def test_ability_modifier_for_score_4_is__3
     skip
     assert_equal(-3, DndCharacter.modifier(4))
   end
 
-  def test_modifier_score_5
+  def test_ability_modifier_for_score_5_is__3
     skip
     assert_equal(-3, DndCharacter.modifier(5))
   end
 
-  def test_modifier_score_6
+  def test_ability_modifier_for_score_6_is__2
     skip
     assert_equal(-2, DndCharacter.modifier(6))
   end
 
-  def test_modifier_score_7
+  def test_ability_modifier_for_score_7_is__2
     skip
     assert_equal(-2, DndCharacter.modifier(7))
   end
 
-  def test_modifier_score_8
+  def test_ability_modifier_for_score_8_is__1
     skip
     assert_equal(-1, DndCharacter.modifier(8))
   end
 
-  def test_modifier_score_9
+  def test_ability_modifier_for_score_9_is__1
     skip
     assert_equal(-1, DndCharacter.modifier(9))
   end
 
-  def test_modifier_score_10
+  def test_ability_modifier_for_score_10_is_0
     skip
-    assert_equal 0, DndCharacter.modifier(10)
+    assert_equal(0, DndCharacter.modifier(10))
   end
 
-  def test_modifier_score_11
+  def test_ability_modifier_for_score_11_is_0
     skip
-    assert_equal 0, DndCharacter.modifier(11)
+    assert_equal(0, DndCharacter.modifier(11))
   end
 
-  def test_modifier_score_12
+  def test_ability_modifier_for_score_12_is_1
     skip
-    assert_equal 1, DndCharacter.modifier(12)
+    assert_equal(1, DndCharacter.modifier(12))
   end
 
-  def test_modifier_score_13
+  def test_ability_modifier_for_score_13_is_1
     skip
-    assert_equal 1, DndCharacter.modifier(13)
+    assert_equal(1, DndCharacter.modifier(13))
   end
 
-  def test_modifier_score_14
+  def test_ability_modifier_for_score_14_is_2
     skip
-    assert_equal 2, DndCharacter.modifier(14)
+    assert_equal(2, DndCharacter.modifier(14))
   end
 
-  def test_modifier_score_15
+  def test_ability_modifier_for_score_15_is_2
     skip
-    assert_equal 2, DndCharacter.modifier(15)
+    assert_equal(2, DndCharacter.modifier(15))
   end
 
-  def test_modifier_score_16
+  def test_ability_modifier_for_score_16_is_3
     skip
-    assert_equal 3, DndCharacter.modifier(16)
+    assert_equal(3, DndCharacter.modifier(16))
   end
 
-  def test_modifier_score_17
+  def test_ability_modifier_for_score_17_is_3
     skip
-    assert_equal 3, DndCharacter.modifier(17)
+    assert_equal(3, DndCharacter.modifier(17))
   end
 
-  def test_modifier_score_18
+  def test_ability_modifier_for_score_18_is_4
     skip
-    assert_equal 4, DndCharacter.modifier(18)
+    assert_equal(4, DndCharacter.modifier(18))
   end
 
   # rubocop:disable Style/FormatString, Style/RedundantPercentQ

From c2d4d9560435abe40bd4d2fb8a5b092b155be2a5 Mon Sep 17 00:00:00 2001
From: meatball <69751659+meatball133@users.noreply.github.com>
Date: Sun, 31 Aug 2025 23:07:07 +0200
Subject: [PATCH 2/6] Fix exercise naming in generator (#1770) (#1777)

* Enhance underscore method to filter invalid characters and update test file naming convention
* Add test case which test underscore for special characters
* Use character classes in regex. Also expose description for nested test cases.
* Underscore must not create multiple underscores around special characters
---
 bin/generate                   |  6 +++++-
 generatorv2/lib/generator.rb   |  6 +++---
 generatorv2/lib/utils.rb       |  2 +-
 generatorv2/test/utils_test.rb | 10 ++++++++++
 4 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/bin/generate b/bin/generate
index fd6f32f277..4966be4299 100755
--- a/bin/generate
+++ b/bin/generate
@@ -9,6 +9,10 @@ def exercises
     .select { |file| File.directory? File.join('./exercises/practice', file) }
 end
 
+def underscore(str)
+  str.gsub(/[^\w\s-]/, '').gsub(/[-\s]/, '_').downcase
+end
+
 class VerificationError < StandardError
   MESSAGE = 'The result generated for %<exercise>s, does not match the current file'
 
@@ -39,7 +43,7 @@ end
 parser.on('--verify', 'Verify all exercises') do
   exercises.each do |exercise|
     if File.exist?("./exercises/practice/#{exercise}/.meta/test_template.erb")
-      current_code = File.read("./exercises/practice/#{exercise}/#{exercise}_test.rb")
+      current_code = File.read("./exercises/practice/#{exercise}/#{underscore(exercise)}_test.rb")
       f = File.new("./exercises/practice/#{exercise}/temp_test.rb", 'w+')
       Generator.new(exercise).generate(f.path)
       generated_code = f.read
diff --git a/generatorv2/lib/generator.rb b/generatorv2/lib/generator.rb
index a0d669e929..5f15b0b43c 100644
--- a/generatorv2/lib/generator.rb
+++ b/generatorv2/lib/generator.rb
@@ -21,17 +21,17 @@ def generate(result_path = "./exercises/practice/#{@exercise}/#{underscore(@exer
     additional_json(json)
     json["cases"] = remove_tests(uuid, json)
     status = proc { status }
-    template = ERB.new File.read("./exercises/practice/#{@exercise}/.meta/test_template.erb")
+    template = ERB.new(File.read("./exercises/practice/#{@exercise}/.meta/test_template.erb"), trim_mode: '-')
 
     result = template.result(binding)
 
     File.write(result_path, result)
     RuboCop::CLI.new.
-      run(['-x', '-c', '.rubocop.yml', '-o', NullDevice.path, result_path])
+      run(['-a', '-c', '.rubocop.yml', '-o', NullDevice.path, result_path])
   end
 
   def underscore(str)
-    str.gsub(/[-\s]/, '_').downcase
+    str.gsub(/[^\w\s-]/, '').gsub('  ', ' ').gsub(/[-\s]/, '_').downcase
   end
 
   def camel_case(str)
diff --git a/generatorv2/lib/utils.rb b/generatorv2/lib/utils.rb
index d6b80971e6..a728848e8c 100644
--- a/generatorv2/lib/utils.rb
+++ b/generatorv2/lib/utils.rb
@@ -47,7 +47,7 @@ def additional_json(json)
   def remove_tests(uuid, json)
     json["cases"].each_with_object([]) do |x, acc|
       if x["cases"]
-        acc << { "cases" => remove_tests(uuid, x) }
+        acc << { "cases" => remove_tests(uuid, x), "description" => x["description"] }
       elsif uuid.include?(x["uuid"])
         acc << x
       end
diff --git a/generatorv2/test/utils_test.rb b/generatorv2/test/utils_test.rb
index 235021882c..944e0b66b8 100644
--- a/generatorv2/test/utils_test.rb
+++ b/generatorv2/test/utils_test.rb
@@ -22,6 +22,16 @@ def test_underscore_with_two_words
       Generator.new("two-fer").underscore("two-fer")
   end
 
+  def test_underscore_with_special_characters
+    assert_equal "two_fer",
+      Generator.new("two-fer").underscore("two,!@#$%^&*()-fer")
+  end
+
+  def test_underscore_with_special_characters_should_not_create_multiple_spaces
+    assert_equal "two_fer",
+      Generator.new("two-fer").underscore("two = fer")
+  end
+
   def test_first_time_includes_hastag
     assert_equal "# skip",
       Generator.new("acronym").skip?

From 169890685e3437d176c3baa7edbf56dcc0bf6f57 Mon Sep 17 00:00:00 2001
From: meatball <meatballsofmeatballs@gmail.com>
Date: Tue, 2 Sep 2025 19:58:26 +0200
Subject: [PATCH 3/6] Change to singel qoutes, change conditional statement

---
 generatorv2/lib/utils.rb | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/generatorv2/lib/utils.rb b/generatorv2/lib/utils.rb
index a728848e8c..c180b29164 100644
--- a/generatorv2/lib/utils.rb
+++ b/generatorv2/lib/utils.rb
@@ -10,7 +10,7 @@ def toml(path = "./exercises/practice/#{@exercise}/.meta/tests.toml")
 
     uuid = TomlRB.load_file(path)
     uuid = uuid.filter do |_k, v|
-      v.none? { |k, inner_value| k == "include" && !inner_value }
+      v.none? { |k, inner_value| k == 'include' && !inner_value }
     end
     uuid.keys
   end
@@ -39,18 +39,18 @@ def additional_json(json)
     file_path = "./exercises/practice/#{@exercise}/.meta/additional_tests.json"
     return unless File.exist?(file_path)
 
-    JSON.parse(File.read(file_path))["cases"].each do |test|
-      json["cases"] << test
+    JSON.parse(File.read(file_path))['cases'].each do |test|
+      json['cases'] << test
     end
   end
 
   def remove_tests(uuid, json)
-    json["cases"].each_with_object([]) do |x, acc|
-      if x["cases"]
-        acc << { "cases" => remove_tests(uuid, x), "description" => x["description"] }
-      elsif uuid.include?(x["uuid"])
-        acc << x
-      end
+    json['cases'].each_with_object([]) do |x, acc|
+      acc << if x['cases']
+               { 'cases' => remove_tests(uuid, x), 'description' => x['description'] }
+             elsif uuid.include?(x['uuid'])
+               x
+             end
     end
   end
 end

From 964c3083cc0b215b81522a0ced3ae9f7229011aa Mon Sep 17 00:00:00 2001
From: meatball <meatballsofmeatballs@gmail.com>
Date: Tue, 2 Sep 2025 19:59:21 +0200
Subject: [PATCH 4/6] add eol

---
 exercises/practice/circular-buffer/.meta/test_template.erb      | 2 +-
 exercises/practice/crypto-square/.meta/test_template.erb        | 2 +-
 exercises/practice/custom-set/.meta/test_template.erb           | 2 +-
 exercises/practice/darts/.meta/test_template.erb                | 2 +-
 exercises/practice/diamond/.meta/test_template.erb              | 2 +-
 .../practice/difference-of-squares/.meta/test_template.erb      | 2 +-
 exercises/practice/dnd-character/.meta/test_template.erb        | 2 +-
 7 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/exercises/practice/circular-buffer/.meta/test_template.erb b/exercises/practice/circular-buffer/.meta/test_template.erb
index 3be26a5f29..dcf255bc44 100644
--- a/exercises/practice/circular-buffer/.meta/test_template.erb
+++ b/exercises/practice/circular-buffer/.meta/test_template.erb
@@ -27,4 +27,4 @@ class CircularBufferTest < Minitest::Test
         <%- end -%>
     end
     <% end %>
-end
\ No newline at end of file
+end
diff --git a/exercises/practice/crypto-square/.meta/test_template.erb b/exercises/practice/crypto-square/.meta/test_template.erb
index 7ab2747dbd..3070e04fdc 100644
--- a/exercises/practice/crypto-square/.meta/test_template.erb
+++ b/exercises/practice/crypto-square/.meta/test_template.erb
@@ -9,4 +9,4 @@ class CryptoSquareTest < Minitest::Test
         assert_equal '<%= cases["expected"] %>', Crypto.new(plaintext).ciphertext
     end
     <% end %>
-end
\ No newline at end of file
+end
diff --git a/exercises/practice/custom-set/.meta/test_template.erb b/exercises/practice/custom-set/.meta/test_template.erb
index 872eb2f016..75c33d6ed1 100644
--- a/exercises/practice/custom-set/.meta/test_template.erb
+++ b/exercises/practice/custom-set/.meta/test_template.erb
@@ -40,4 +40,4 @@ class CustomSetTest < Minitest::Test
         end
     <% end %>
 <% end %>
-end
\ No newline at end of file
+end
diff --git a/exercises/practice/darts/.meta/test_template.erb b/exercises/practice/darts/.meta/test_template.erb
index a5ad83d9fe..3f915148fa 100644
--- a/exercises/practice/darts/.meta/test_template.erb
+++ b/exercises/practice/darts/.meta/test_template.erb
@@ -9,4 +9,4 @@ class DartsTest < Minitest::Test
         assert_equal(<%= cases["expected"] %>, darts.score)
     end
     <% end %>
-end
\ No newline at end of file
+end
diff --git a/exercises/practice/diamond/.meta/test_template.erb b/exercises/practice/diamond/.meta/test_template.erb
index ff29ea8d18..4d8458e773 100644
--- a/exercises/practice/diamond/.meta/test_template.erb
+++ b/exercises/practice/diamond/.meta/test_template.erb
@@ -12,4 +12,4 @@ class DiamondTest < Minitest::Test
         assert_equal string, answer
     end
     <% end %>
-end
\ No newline at end of file
+end
diff --git a/exercises/practice/difference-of-squares/.meta/test_template.erb b/exercises/practice/difference-of-squares/.meta/test_template.erb
index 85e8865cfa..53880e8ce9 100644
--- a/exercises/practice/difference-of-squares/.meta/test_template.erb
+++ b/exercises/practice/difference-of-squares/.meta/test_template.erb
@@ -10,4 +10,4 @@ class DifferenceOfSquaresTest < Minitest::Test
         end
     <% end %>
 <% end %>
-end
\ No newline at end of file
+end
diff --git a/exercises/practice/dnd-character/.meta/test_template.erb b/exercises/practice/dnd-character/.meta/test_template.erb
index e841b1d8de..2fc7b96355 100644
--- a/exercises/practice/dnd-character/.meta/test_template.erb
+++ b/exercises/practice/dnd-character/.meta/test_template.erb
@@ -66,4 +66,4 @@ class DndCharacterTest < Minitest::Test
     end
     # rubocop:enable Style/FormatString, Style/RedundantPercentQ
   end
-end
\ No newline at end of file
+end

From 1b71ff2d75a71cdad1dc0352f97431fa83eb18db Mon Sep 17 00:00:00 2001
From: meatball <meatballsofmeatballs@gmail.com>
Date: Tue, 2 Sep 2025 20:26:13 +0200
Subject: [PATCH 5/6] Rollback changes due to errors

---
 generatorv2/lib/utils.rb | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/generatorv2/lib/utils.rb b/generatorv2/lib/utils.rb
index c180b29164..86bd6a0ed3 100644
--- a/generatorv2/lib/utils.rb
+++ b/generatorv2/lib/utils.rb
@@ -46,11 +46,11 @@ def additional_json(json)
 
   def remove_tests(uuid, json)
     json['cases'].each_with_object([]) do |x, acc|
-      acc << if x['cases']
-               { 'cases' => remove_tests(uuid, x), 'description' => x['description'] }
-             elsif uuid.include?(x['uuid'])
-               x
-             end
+      if x['cases']
+        acc << { 'cases' => remove_tests(uuid, x), 'description' => x['description'] }
+      elsif uuid.include?(x['uuid'])
+        acc << x
+      end
     end
   end
 end

From 6007953c8690b6cf517c0f5463bde461abb0222f Mon Sep 17 00:00:00 2001
From: meatball <meatballsofmeatballs@gmail.com>
Date: Sun, 7 Sep 2025 12:48:48 +0200
Subject: [PATCH 6/6] Remove trailling spaces

---
 exercises/practice/circular-buffer/.meta/test_template.erb      | 2 +-
 exercises/practice/crypto-square/.meta/test_template.erb        | 2 +-
 exercises/practice/darts/.meta/test_template.erb                | 2 +-
 exercises/practice/diamond/.meta/test_template.erb              | 2 +-
 .../practice/difference-of-squares/.meta/test_template.erb      | 2 +-
 5 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/exercises/practice/circular-buffer/.meta/test_template.erb b/exercises/practice/circular-buffer/.meta/test_template.erb
index dcf255bc44..dedd77d4b6 100644
--- a/exercises/practice/circular-buffer/.meta/test_template.erb
+++ b/exercises/practice/circular-buffer/.meta/test_template.erb
@@ -4,7 +4,7 @@ require_relative 'circular_buffer'
 class CircularBufferTest < Minitest::Test
 <% json["cases"].each do |cases| %>
     def test_<%= underscore(cases["description"]) %>
-        <%= skip? %> 
+        <%= skip? %>
         buffer = CircularBuffer.new(<%= cases["input"]["capacity"] %>)
         <%- cases["input"]["operations"].each do |operation| -%>
             <%- if operation["operation"] == "read"-%>
diff --git a/exercises/practice/crypto-square/.meta/test_template.erb b/exercises/practice/crypto-square/.meta/test_template.erb
index 3070e04fdc..101b09556b 100644
--- a/exercises/practice/crypto-square/.meta/test_template.erb
+++ b/exercises/practice/crypto-square/.meta/test_template.erb
@@ -4,7 +4,7 @@ require_relative 'crypto_square'
 class CryptoSquareTest < Minitest::Test
 <% json["cases"].each do |cases| %>
     def test_<%= underscore(cases["description"]) %>
-        <%= skip? %> 
+        <%= skip? %>
         plaintext = '<%= cases["input"]["plaintext"] %>'
         assert_equal '<%= cases["expected"] %>', Crypto.new(plaintext).ciphertext
     end
diff --git a/exercises/practice/darts/.meta/test_template.erb b/exercises/practice/darts/.meta/test_template.erb
index 3f915148fa..abb30703af 100644
--- a/exercises/practice/darts/.meta/test_template.erb
+++ b/exercises/practice/darts/.meta/test_template.erb
@@ -4,7 +4,7 @@ require_relative 'darts'
 class DartsTest < Minitest::Test
 <% json["cases"].each do |cases| %>
     def test_<%= underscore(cases["description"]) %>
-        <%= skip? %> 
+        <%= skip? %>
         darts = Darts.new(<%= cases["input"]["x"] %>, <%= cases["input"]["y"] %>)
         assert_equal(<%= cases["expected"] %>, darts.score)
     end
diff --git a/exercises/practice/diamond/.meta/test_template.erb b/exercises/practice/diamond/.meta/test_template.erb
index 4d8458e773..c1db095d5d 100644
--- a/exercises/practice/diamond/.meta/test_template.erb
+++ b/exercises/practice/diamond/.meta/test_template.erb
@@ -4,7 +4,7 @@ require_relative 'diamond'
 class DiamondTest < Minitest::Test
 <% json["cases"].each do |cases| %>
     def test_<%= underscore(cases["description"]) %>
-        <%= skip? %> 
+        <%= skip? %>
         answer = Diamond.make_diamond('<%= cases["input"]["letter"] %>')
         string =<% cases["expected"].each do |row| -%>
                 "<%= row %>\n"\
diff --git a/exercises/practice/difference-of-squares/.meta/test_template.erb b/exercises/practice/difference-of-squares/.meta/test_template.erb
index 53880e8ce9..38bf92ca72 100644
--- a/exercises/practice/difference-of-squares/.meta/test_template.erb
+++ b/exercises/practice/difference-of-squares/.meta/test_template.erb
@@ -5,7 +5,7 @@ class DifferenceOfSquaresTest < Minitest::Test
 <% json["cases"].each do |cases| %>
     <% cases["cases"].each do |sub_case| %>
         def test_<%= underscore(sub_case["description"]) %>
-            <%= skip? %> 
+            <%= skip? %>
             assert_equal <%= sub_case["expected"] %>, Squares.new(<%= sub_case["input"]["number"] %>).<%= sub_case["property"] == "differenceOfSquares" ? "difference" : sub_case["property"].gsub(/([A-Z])/, '_\1').downcase.sub(/^_/, '') %>
         end
     <% end %>