From 6a4d2eab72e679ebbea54559b5b48264106382a8 Mon Sep 17 00:00:00 2001
From: Geoff Hubbard <ghub@instihost.com>
Date: Thu, 8 Jun 2017 08:56:54 +0100
Subject: [PATCH 1/3] collatz-conjecture: New exercise with test generator

---
 exercises/collatz-conjecture/.meta/.version   |  1 +
 .../generator/collatz_conjecture_case.rb      | 31 ++++++++++
 .../.meta/solutions/collatz_conjecture.rb     | 22 +++++++
 .../collatz_conjecture_test.rb                | 58 +++++++++++++++++++
 4 files changed, 112 insertions(+)
 create mode 100644 exercises/collatz-conjecture/.meta/.version
 create mode 100644 exercises/collatz-conjecture/.meta/generator/collatz_conjecture_case.rb
 create mode 100644 exercises/collatz-conjecture/.meta/solutions/collatz_conjecture.rb
 create mode 100644 exercises/collatz-conjecture/collatz_conjecture_test.rb

diff --git a/exercises/collatz-conjecture/.meta/.version b/exercises/collatz-conjecture/.meta/.version
new file mode 100644
index 0000000000..56a6051ca2
--- /dev/null
+++ b/exercises/collatz-conjecture/.meta/.version
@@ -0,0 +1 @@
+1
\ No newline at end of file
diff --git a/exercises/collatz-conjecture/.meta/generator/collatz_conjecture_case.rb b/exercises/collatz-conjecture/.meta/generator/collatz_conjecture_case.rb
new file mode 100644
index 0000000000..0d0804c271
--- /dev/null
+++ b/exercises/collatz-conjecture/.meta/generator/collatz_conjecture_case.rb
@@ -0,0 +1,31 @@
+require 'generator/exercise_case'
+
+class CollatzConjectureCase < Generator::ExerciseCase
+  using Generator::Underscore
+
+  def workload
+    case expected
+    when Fixnum
+      standard_assertion
+    when Hash
+      error_assertion
+    end
+  end
+
+  def standard_assertion
+    assert_equal { subject_of_test }
+  end
+
+  def error_assertion
+    "assert_raises(ArgumentError) { #{subject_of_test} }"
+  end
+
+  def subject_of_test
+    "CollatzConjecture.steps(#{input})"
+  end
+
+  def input
+    number.underscore
+  end
+end
+
diff --git a/exercises/collatz-conjecture/.meta/solutions/collatz_conjecture.rb b/exercises/collatz-conjecture/.meta/solutions/collatz_conjecture.rb
new file mode 100644
index 0000000000..61b140d86e
--- /dev/null
+++ b/exercises/collatz-conjecture/.meta/solutions/collatz_conjecture.rb
@@ -0,0 +1,22 @@
+module BookKeeping
+  VERSION = 1
+end
+
+module CollatzConjecture
+  def self.steps(num)
+    raise ArgumentError if num < 1
+    n = num
+    steps = 0
+    until n == 1
+      steps += 1
+      if n.even?
+        n /= 2
+      else
+        n = 3 * n + 1
+      end
+    end
+    steps
+  end
+end
+
+
diff --git a/exercises/collatz-conjecture/collatz_conjecture_test.rb b/exercises/collatz-conjecture/collatz_conjecture_test.rb
new file mode 100644
index 0000000000..33dad0490b
--- /dev/null
+++ b/exercises/collatz-conjecture/collatz_conjecture_test.rb
@@ -0,0 +1,58 @@
+#!/usr/bin/env ruby
+require 'minitest/autorun'
+require_relative 'collatz_conjecture'
+
+# Common test data version: 1.1.1 25c4479
+class CollatzConjectureTest < Minitest::Test
+  def test_zero_steps_for_one
+    # skip
+    assert_equal 0, CollatzConjecture.steps(1)
+  end
+
+  def test_divide_if_even
+    skip
+    assert_equal 4, CollatzConjecture.steps(16)
+  end
+
+  def test_even_and_odd_steps
+    skip
+    assert_equal 9, CollatzConjecture.steps(12)
+  end
+
+  def test_large_number_of_even_and_odd_steps
+    skip
+    assert_equal 152, CollatzConjecture.steps(1_000_000)
+  end
+
+  def test_zero_is_an_error
+    skip
+    assert_raises(ArgumentError) { CollatzConjecture.steps(0) }
+  end
+
+  def test_negative_value_is_an_error
+    skip
+    assert_raises(ArgumentError) { CollatzConjecture.steps(-15) }
+  end
+
+  # Problems in exercism evolve over time, as we find better ways to ask
+  # questions.
+  # The version number refers to the version of the problem you solved,
+  # not your solution.
+  #
+  # Define a constant named VERSION inside of the top level BookKeeping
+  # module, which may be placed near the end of your file.
+  #
+  # In your file, it will look like this:
+  #
+  # module BookKeeping
+  #   VERSION = 1 # Where the version number matches the one in the test.
+  # end
+  #
+  # If you are curious, read more about constants on RubyDoc:
+  # http://ruby-doc.org/docs/ruby-doc-bundle/UsersGuide/rg/constants.html
+
+  def test_bookkeeping
+    skip
+    assert_equal 1, BookKeeping::VERSION
+  end
+end

From 23415aabd0a0a567ec7b7f8641fb5a88813efb75 Mon Sep 17 00:00:00 2001
From: Geoff Hubbard <ghub@instihost.com>
Date: Thu, 8 Jun 2017 10:04:33 +0100
Subject: [PATCH 2/3] Set executable bit on test file.

---
 exercises/collatz-conjecture/collatz_conjecture_test.rb | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 mode change 100644 => 100755 exercises/collatz-conjecture/collatz_conjecture_test.rb

diff --git a/exercises/collatz-conjecture/collatz_conjecture_test.rb b/exercises/collatz-conjecture/collatz_conjecture_test.rb
old mode 100644
new mode 100755

From b1a05ab931f9e5bdee02e526871afc2c917e19d2 Mon Sep 17 00:00:00 2001
From: Geoff Hubbard <ghub@instihost.com>
Date: Thu, 8 Jun 2017 10:10:22 +0100
Subject: [PATCH 3/3] Add collatz-conjecture to config.json

---
 config.json | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/config.json b/config.json
index 9a605b8a48..799bd906b7 100644
--- a/config.json
+++ b/config.json
@@ -593,6 +593,18 @@
       "topics": [
 
       ]
+    },
+    {
+      "slug": "collatz-conjecture",
+      "difficulty": 1,
+      "topics": [
+        "Control-flow (loops)",
+        "Control-flow (conditionals)",
+        "Recursion",
+        "Integers",
+        "Algorithms",
+        "Mathematics"
+      ]
     }
   ],
   "deprecated": [