From 5ed1c0815233b09db7d97e1bd0735a4b6206d31f Mon Sep 17 00:00:00 2001
From: Lidiane Taquehara <lidi.mayra@gmail.com>
Date: Wed, 13 Jul 2016 11:03:32 +0000
Subject: [PATCH 1/3] Class method to calculate Coefficient of Variation

---
 lib/descriptive_statistics/coefficient_of_variation.rb | 8 ++++++++
 lib/descriptive_statistics/descriptive_statistics.rb   | 1 +
 lib/descriptive_statistics/safe.rb                     | 1 +
 spec/safe/class_method_spec.rb                         | 4 ++++
 4 files changed, 14 insertions(+)
 create mode 100644 lib/descriptive_statistics/coefficient_of_variation.rb

diff --git a/lib/descriptive_statistics/coefficient_of_variation.rb b/lib/descriptive_statistics/coefficient_of_variation.rb
new file mode 100644
index 0000000..7cf68e1
--- /dev/null
+++ b/lib/descriptive_statistics/coefficient_of_variation.rb
@@ -0,0 +1,8 @@
+module DescriptiveStatistics
+  def coefficient_of_variation(collection = self, &block)
+    values = Support::convert(collection, &block)
+    return DescriptiveStatistics.coefficient_of_variation_empty_collection_default_value if values.empty?
+
+    values.standard_deviation / values.mean
+  end
+end
diff --git a/lib/descriptive_statistics/descriptive_statistics.rb b/lib/descriptive_statistics/descriptive_statistics.rb
index 1a35fed..89e5bb1 100644
--- a/lib/descriptive_statistics/descriptive_statistics.rb
+++ b/lib/descriptive_statistics/descriptive_statistics.rb
@@ -4,6 +4,7 @@ def descriptive_statistics(&block)
              :sum => self.sum(&block),
              :variance => self.variance(&block),
              :standard_deviation => self.standard_deviation(&block),
+	      :coefficient_of_variation => self.coefficient_of_variation(&block),
              :min => self.min(&block),
              :max => self.max(&block),
              :mean => self.mean(&block),
diff --git a/lib/descriptive_statistics/safe.rb b/lib/descriptive_statistics/safe.rb
index 9c45acd..0ce8796 100644
--- a/lib/descriptive_statistics/safe.rb
+++ b/lib/descriptive_statistics/safe.rb
@@ -6,6 +6,7 @@
 require 'descriptive_statistics/mode.rb'
 require 'descriptive_statistics/variance.rb'
 require 'descriptive_statistics/standard_deviation.rb'
+require 'descriptive_statistics/coefficient_of_variation.rb'
 require 'descriptive_statistics/percentile.rb'
 require 'descriptive_statistics/percentile_rank.rb'
 require 'descriptive_statistics/range.rb'
diff --git a/spec/safe/class_method_spec.rb b/spec/safe/class_method_spec.rb
index 53d93a3..41be8ce 100644
--- a/spec/safe/class_method_spec.rb
+++ b/spec/safe/class_method_spec.rb
@@ -32,6 +32,10 @@
       expect(subject.standard_deviation(data)).to eql(2.778310325442932)
     end
 
+    it "calculates the coefficient of variation" do
+      expect(subject.coefficient_of_variation(data)).to eql (0.5659521033309676)
+    end
+
     it "calculates the percentile" do
       expect(subject.percentile(30, data)).to eql(3.0)
       expect(subject.percentile(50, data)).to eql(5.0)

From 097fd8e021c442335a8ef117b378f7b18ade4357 Mon Sep 17 00:00:00 2001
From: Lidiane Taquehara <lidi.mayra@gmail.com>
Date: Thu, 14 Jul 2016 05:22:22 -0300
Subject: [PATCH 2/3] =?UTF-8?q?Implementa=C3=A7=C3=A3o=20de=20specs?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../descriptive_statistics.rb                  |  2 +-
 spec/monkeypatch/array_spec.rb                 |  6 +++++-
 spec/monkeypatch/empty_collection_spec.rb      | 18 +++++++++++++++++-
 spec/monkeypatch/hash_spec.rb                  |  6 +++++-
 spec/monkeypatch/object_spec.rb                |  6 +++++-
 spec/monkeypatch/set_spec.rb                   |  6 +++++-
 spec/monkeypatch/single_value_spec.rb          |  6 +++++-
 spec/safe/class_method_spec.rb                 |  4 ++--
 spec/safe/extend_spec.rb                       |  6 +++++-
 spec/safe/stats_spec.rb                        |  6 +++++-
 10 files changed, 55 insertions(+), 11 deletions(-)

diff --git a/lib/descriptive_statistics/descriptive_statistics.rb b/lib/descriptive_statistics/descriptive_statistics.rb
index 89e5bb1..b88e551 100644
--- a/lib/descriptive_statistics/descriptive_statistics.rb
+++ b/lib/descriptive_statistics/descriptive_statistics.rb
@@ -4,7 +4,7 @@ def descriptive_statistics(&block)
              :sum => self.sum(&block),
              :variance => self.variance(&block),
              :standard_deviation => self.standard_deviation(&block),
-	      :coefficient_of_variation => self.coefficient_of_variation(&block),
+             :coefficient_of_variation => self.coefficient_of_variation(&block),
              :min => self.min(&block),
              :max => self.max(&block),
              :mean => self.mean(&block),
diff --git a/spec/monkeypatch/array_spec.rb b/spec/monkeypatch/array_spec.rb
index 6f65437..a7130d5 100644
--- a/spec/monkeypatch/array_spec.rb
+++ b/spec/monkeypatch/array_spec.rb
@@ -37,6 +37,10 @@
       expect(subject.standard_deviation).to eql(2.778310325442932)
     end
 
+    it "calculates the coefficient of variation" do
+      expect(subject.coefficient_of_variation).to eql(0.5659521033309676)
+    end
+
     it "calculates the percentile" do
       expect(subject.percentile(30)).to eql(3.0)
       expect(subject.percentile(50)).to eql(5.0)
@@ -61,4 +65,4 @@
 
    end
 
-end
\ No newline at end of file
+end
diff --git a/spec/monkeypatch/empty_collection_spec.rb b/spec/monkeypatch/empty_collection_spec.rb
index 4a74b73..78dcf9d 100644
--- a/spec/monkeypatch/empty_collection_spec.rb
+++ b/spec/monkeypatch/empty_collection_spec.rb
@@ -35,6 +35,10 @@
       expect(subject.standard_deviation).to eql(nil)
     end
 
+    it "calculates the coefficient of variation" do
+      expect(subject.coefficient_of_variation).to eql(nil)
+    end
+
     it "calculates the percentile" do
       expect(subject.percentile(30)).to eql(nil)
       expect(subject.percentile(50)).to eql(nil)
@@ -93,6 +97,10 @@
       expect(subject.standard_deviation).to eql(0.0)
     end
 
+    it "calculates the coefficient of variation" do
+      expect(subject.coefficient_of_variation).to eql(0.0)
+    end
+
     it "calculates the percentile" do
       expect(subject.percentile(30)).to eql(0.0)
       expect(subject.percentile(50)).to eql(0.0)
@@ -148,6 +156,10 @@
       expect(subject.standard_deviation).to eql(nil)
     end
 
+    it "calculates the coefficient_of_variation" do
+      expect(subject.coefficient_of_variation).to eql(nil)
+    end
+
     it "calculates the percentile" do
       expect(subject.percentile(30)).to eql(nil)
       expect(subject.percentile(50)).to eql(nil)
@@ -203,6 +215,10 @@
       expect(subject.standard_deviation).to eql(nil)
     end
 
+    it "calculates the coefficient_of_variation" do
+      expect(subject.coefficient_of_variation).to eql(nil)
+    end
+
     it "calculates the percentile" do
       expect(subject.percentile(30)).to eql(nil)
       expect(subject.percentile(50)).to eql(nil)
@@ -227,4 +243,4 @@
 
   end
 
-end
\ No newline at end of file
+end
diff --git a/spec/monkeypatch/hash_spec.rb b/spec/monkeypatch/hash_spec.rb
index 0422d5f..f475716 100644
--- a/spec/monkeypatch/hash_spec.rb
+++ b/spec/monkeypatch/hash_spec.rb
@@ -37,6 +37,10 @@
       expect(subject.standard_deviation).to eql(2.778310325442932)
     end
 
+    it "calculates the coefficient_of_variation" do
+      expect(subject.coefficient_of_variation).to eql(0.5659521033309676)
+    end
+
     it "calculates the percentile" do
       expect(subject.percentile(30)).to eql(3.0)
       expect(subject.percentile(50)).to eql(5.0)
@@ -61,4 +65,4 @@
 
    end
 
-end
\ No newline at end of file
+end
diff --git a/spec/monkeypatch/object_spec.rb b/spec/monkeypatch/object_spec.rb
index 574a1ef..b4a83d0 100644
--- a/spec/monkeypatch/object_spec.rb
+++ b/spec/monkeypatch/object_spec.rb
@@ -41,6 +41,10 @@
         expect(subject.standard_deviation(&:price)).to eql(2.0850659461993044)
       end
 
+      it "calculates the coefficient_of_variation" do
+        expect(subject.coefficient_of_variation(&:price)).to eql(0.6043669409273346)
+      end
+
       it "calculates the percentile" do
         expect(subject.percentile(30, &:price)).to eql(2.3)
         expect(subject.percentile(50, &:price)).to eql(3.8)
@@ -116,4 +120,4 @@
     end
    end
 
-end
\ No newline at end of file
+end
diff --git a/spec/monkeypatch/set_spec.rb b/spec/monkeypatch/set_spec.rb
index 77e5951..a77781c 100644
--- a/spec/monkeypatch/set_spec.rb
+++ b/spec/monkeypatch/set_spec.rb
@@ -37,6 +37,10 @@
       expect(subject.standard_deviation).to eql(2.799416848895061)
     end
 
+    it "calculates the coefficient_of_variation" do
+      expect(subject.coefficient_of_variation).to eql(0.576350527713689)
+    end
+
     it "calculates the percentile" do
       expect(subject.percentile(30)).to eql(2.8)
       expect(subject.percentile(50)).to eql(5.0)
@@ -61,4 +65,4 @@
 
    end
 
-end
\ No newline at end of file
+end
diff --git a/spec/monkeypatch/single_value_spec.rb b/spec/monkeypatch/single_value_spec.rb
index 1c09711..56b8f4a 100644
--- a/spec/monkeypatch/single_value_spec.rb
+++ b/spec/monkeypatch/single_value_spec.rb
@@ -31,6 +31,10 @@
       expect(subject.standard_deviation).to eql(0.0)
     end
 
+    it "calculates the coefficient_of_variation" do
+      expect(subject.coefficient_of_variation).to eql(0.0)
+    end
+
     it "calculates the percentile" do
       expect(subject.percentile(30)).to eql(2.0)
       expect(subject.percentile(50)).to eql(2.0)
@@ -55,4 +59,4 @@
 
    end
 
-end
\ No newline at end of file
+end
diff --git a/spec/safe/class_method_spec.rb b/spec/safe/class_method_spec.rb
index 41be8ce..44c35fd 100644
--- a/spec/safe/class_method_spec.rb
+++ b/spec/safe/class_method_spec.rb
@@ -33,7 +33,7 @@
     end
 
     it "calculates the coefficient of variation" do
-      expect(subject.coefficient_of_variation(data)).to eql (0.5659521033309676)
+      expect(subject.coefficient_of_variation(data)).to eql(0.5659521033309676)
     end
 
     it "calculates the percentile" do
@@ -60,4 +60,4 @@
 
    end
 
-end
\ No newline at end of file
+end
diff --git a/spec/safe/extend_spec.rb b/spec/safe/extend_spec.rb
index a34356f..324f8be 100644
--- a/spec/safe/extend_spec.rb
+++ b/spec/safe/extend_spec.rb
@@ -42,6 +42,10 @@
       expect(subject.standard_deviation).to eql(2.778310325442932)
     end
 
+    it "calculates the coefficient of variation" do
+      expect(subject.coefficient_of_variation).to eql (0.5659521033309676)
+    end
+
     it "calculates the percentile" do
       expect(subject.percentile(30)).to eql(3.0)
       expect(subject.percentile(50)).to eql(5.0)
@@ -66,4 +70,4 @@
 
    end
 
-end
\ No newline at end of file
+end
diff --git a/spec/safe/stats_spec.rb b/spec/safe/stats_spec.rb
index 1cd3d57..b6202a1 100644
--- a/spec/safe/stats_spec.rb
+++ b/spec/safe/stats_spec.rb
@@ -31,6 +31,10 @@
       expect(subject.standard_deviation).to eql(2.778310325442932)
     end
 
+    it "calculates the coefficient of variation" do
+      expect(subject.coefficient_of_variation).to eql (0.5659521033309676)
+    end
+
     it "calculates the percentile" do
       expect(subject.percentile(30)).to eql(3.0)
       expect(subject.percentile(50)).to eql(5.0)
@@ -55,4 +59,4 @@
 
    end
 
-end
\ No newline at end of file
+end

From 72d851090ddba7bca0a3e5a1376c689f7c0ce6a3 Mon Sep 17 00:00:00 2001
From: Lidiane Taquehara <lidi.mayra@gmail.com>
Date: Thu, 14 Jul 2016 07:04:33 -0300
Subject: [PATCH 3/3] Broke conditional in lines (too long)

---
 lib/descriptive_statistics/coefficient_of_variation.rb | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/descriptive_statistics/coefficient_of_variation.rb b/lib/descriptive_statistics/coefficient_of_variation.rb
index 7cf68e1..4a87177 100644
--- a/lib/descriptive_statistics/coefficient_of_variation.rb
+++ b/lib/descriptive_statistics/coefficient_of_variation.rb
@@ -1,7 +1,10 @@
 module DescriptiveStatistics
   def coefficient_of_variation(collection = self, &block)
     values = Support::convert(collection, &block)
-    return DescriptiveStatistics.coefficient_of_variation_empty_collection_default_value if values.empty?
+
+    if values.empty?
+      return DescriptiveStatistics.coefficient_of_variation_empty_collection_default_value
+    end
 
     values.standard_deviation / values.mean
   end