diff --git a/lib/youplot/backends/processing.rb b/lib/youplot/backends/processing.rb
index c6b8ca2..ab373a9 100644
--- a/lib/youplot/backends/processing.rb
+++ b/lib/youplot/backends/processing.rb
@@ -15,8 +15,10 @@ module YouPlot
           arr.value_counts(dropna: false)
         end
           .sort do |a, b|
-            r = b[1] <=> a[1]           # compare values
-            r = a[0] <=> b[0] if r == 0 # If the values are the same, compare by name
+            # compare values
+            r = b[1] <=> a[1]
+            # If the values are the same, compare by name
+            r = a[0] <=> b[0] if r == 0
             r
           end
           .transpose
diff --git a/test/youplot/iris_test.rb b/test/youplot/iris_test.rb
index 985d0c0..aece61d 100644
--- a/test/youplot/iris_test.rb
+++ b/test/youplot/iris_test.rb
@@ -34,19 +34,14 @@ class YouPlotIRISTest < Test::Unit::TestCase
     File.read(File.expand_path("../fixtures/#{fname}", __dir__))
   end
 
-  test :bar do
-    YouPlot::Command.new(['bar', '-H', '-d,', '-t', 'IRIS-BARPLOT']).run
-    assert_equal fixture('iris-barplot.txt'), @stderr_file.read
-  end
-
   test :barplot do
     YouPlot::Command.new(['barplot', '-H', '-d,', '-t', 'IRIS-BARPLOT']).run
     assert_equal fixture('iris-barplot.txt'), @stderr_file.read
   end
 
-  test :hist do
-    YouPlot::Command.new(['hist', '-H', '-d,', '-t', 'IRIS-HISTOGRAM']).run
-    assert_equal fixture('iris-histogram.txt'), @stderr_file.read
+  test :bar do
+    YouPlot::Command.new(['bar', '-H', '-d,', '-t', 'IRIS-BARPLOT']).run
+    assert_equal fixture('iris-barplot.txt'), @stderr_file.read
   end
 
   test :histogram do
@@ -54,9 +49,9 @@ class YouPlotIRISTest < Test::Unit::TestCase
     assert_equal fixture('iris-histogram.txt'), @stderr_file.read
   end
 
-  test :line do
-    YouPlot::Command.new(['line', '-H', '-d,', '-t', 'IRIS-LINEPLOT']).run
-    assert_equal fixture('iris-lineplot.txt'), @stderr_file.read
+  test :hist do
+    YouPlot::Command.new(['hist', '-H', '-d,', '-t', 'IRIS-HISTOGRAM']).run
+    assert_equal fixture('iris-histogram.txt'), @stderr_file.read
   end
 
   test :lineplot do
@@ -64,9 +59,9 @@ class YouPlotIRISTest < Test::Unit::TestCase
     assert_equal fixture('iris-lineplot.txt'), @stderr_file.read
   end
 
-  test :lines do
-    YouPlot::Command.new(['lines', '-H', '-d,', '-t', 'IRIS-LINEPLOTS']).run
-    assert_equal fixture('iris-lineplots.txt'), @stderr_file.read
+  test :line do
+    YouPlot::Command.new(['line', '-H', '-d,', '-t', 'IRIS-LINEPLOT']).run
+    assert_equal fixture('iris-lineplot.txt'), @stderr_file.read
   end
 
   test :lineplots do
@@ -74,9 +69,9 @@ class YouPlotIRISTest < Test::Unit::TestCase
     assert_equal fixture('iris-lineplots.txt'), @stderr_file.read
   end
 
-  test :s do
-    YouPlot::Command.new(['s', '-H', '-d,', '-t', 'IRIS-SCATTER']).run
-    assert_equal fixture('iris-scatter.txt'), @stderr_file.read
+  test :lines do
+    YouPlot::Command.new(['lines', '-H', '-d,', '-t', 'IRIS-LINEPLOTS']).run
+    assert_equal fixture('iris-lineplots.txt'), @stderr_file.read
   end
 
   test :scatter do
@@ -84,9 +79,9 @@ class YouPlotIRISTest < Test::Unit::TestCase
     assert_equal fixture('iris-scatter.txt'), @stderr_file.read
   end
 
-  test :d do
-    YouPlot::Command.new(['d', '-H', '-d,', '-t', 'IRIS-DENSITY']).run
-    assert_equal fixture('iris-density.txt'), @stderr_file.read
+  test :s do
+    YouPlot::Command.new(['s', '-H', '-d,', '-t', 'IRIS-SCATTER']).run
+    assert_equal fixture('iris-scatter.txt'), @stderr_file.read
   end
 
   test :density do
@@ -94,9 +89,9 @@ class YouPlotIRISTest < Test::Unit::TestCase
     assert_equal fixture('iris-density.txt'), @stderr_file.read
   end
 
-  test :box do
-    YouPlot::Command.new(['box', '-H', '-d,', '-t', 'IRIS-BOXPLOT']).run
-    assert_equal fixture('iris-boxplot.txt'), @stderr_file.read
+  test :d do
+    YouPlot::Command.new(['d', '-H', '-d,', '-t', 'IRIS-DENSITY']).run
+    assert_equal fixture('iris-density.txt'), @stderr_file.read
   end
 
   test :boxplot do
@@ -104,6 +99,11 @@ class YouPlotIRISTest < Test::Unit::TestCase
     assert_equal fixture('iris-boxplot.txt'), @stderr_file.read
   end
 
+  test :box do
+    YouPlot::Command.new(['box', '-H', '-d,', '-t', 'IRIS-BOXPLOT']).run
+    assert_equal fixture('iris-boxplot.txt'), @stderr_file.read
+  end
+
   # test :c do
   #   YouPlot::Command.new(['count', '-H', '-d,']).run
   #   assert_equal fixture('iris-count.txt'), @stderr_file.read
diff --git a/test/youplot/simple_test.rb b/test/youplot/simple_test.rb
index 8c3a121..ac0d8d9 100644
--- a/test/youplot/simple_test.rb
+++ b/test/youplot/simple_test.rb
@@ -34,11 +34,8 @@ class YouPlotSimpleTest < Test::Unit::TestCase
     File.read(File.expand_path("../fixtures/#{fname}", __dir__))
   end
 
-  test :bar do
-    assert_raise(ArgumentError) do
-      YouPlot::Command.new(['bar']).run
-    end
-  end
+  # Single command
+  # The goal is to verify that the command works without any options.
 
   test :barplot do
     assert_raise(ArgumentError) do
@@ -46,9 +43,10 @@ class YouPlotSimpleTest < Test::Unit::TestCase
     end
   end
 
-  test :hist do
-    YouPlot::Command.new(['hist']).run
-    assert_equal fixture('simple-histogram.txt'), @stderr_file.read
+  test :bar do
+    assert_raise(ArgumentError) do
+      YouPlot::Command.new(['bar']).run
+    end
   end
 
   test :histogram do
@@ -56,9 +54,9 @@ class YouPlotSimpleTest < Test::Unit::TestCase
     assert_equal fixture('simple-histogram.txt'), @stderr_file.read
   end
 
-  test :line do
-    YouPlot::Command.new(['line']).run
-    assert_equal fixture('simple-lineplot.txt'), @stderr_file.read
+  test :hist do
+    YouPlot::Command.new(['hist']).run
+    assert_equal fixture('simple-histogram.txt'), @stderr_file.read
   end
 
   test :lineplot do
@@ -66,10 +64,9 @@ class YouPlotSimpleTest < Test::Unit::TestCase
     assert_equal fixture('simple-lineplot.txt'), @stderr_file.read
   end
 
-  test :lines do
-    assert_raise(YouPlot::Backends::UnicodePlot::Error) do
-      YouPlot::Command.new(['lines']).run
-    end
+  test :line do
+    YouPlot::Command.new(['line']).run
+    assert_equal fixture('simple-lineplot.txt'), @stderr_file.read
   end
 
   test :lineplots do
@@ -78,9 +75,9 @@ class YouPlotSimpleTest < Test::Unit::TestCase
     end
   end
 
-  test :s do
+  test :lines do
     assert_raise(YouPlot::Backends::UnicodePlot::Error) do
-      YouPlot::Command.new(['s']).run
+      YouPlot::Command.new(['lines']).run
     end
   end
 
@@ -90,9 +87,9 @@ class YouPlotSimpleTest < Test::Unit::TestCase
     end
   end
 
-  test :d do
+  test :s do
     assert_raise(YouPlot::Backends::UnicodePlot::Error) do
-      YouPlot::Command.new(['d']).run
+      YouPlot::Command.new(['s']).run
     end
   end
 
@@ -102,9 +99,10 @@ class YouPlotSimpleTest < Test::Unit::TestCase
     end
   end
 
-  test :box do
-    YouPlot::Command.new(['box']).run
-    assert_equal fixture('simple-boxplot.txt'), @stderr_file.read
+  test :d do
+    assert_raise(YouPlot::Backends::UnicodePlot::Error) do
+      YouPlot::Command.new(['d']).run
+    end
   end
 
   test :boxplot do
@@ -112,9 +110,9 @@ class YouPlotSimpleTest < Test::Unit::TestCase
     assert_equal fixture('simple-boxplot.txt'), @stderr_file.read
   end
 
-  test :c do
-    YouPlot::Command.new(['count']).run
-    assert_equal fixture('simple-count.txt'), @stderr_file.read
+  test :box do
+    YouPlot::Command.new(['box']).run
+    assert_equal fixture('simple-boxplot.txt'), @stderr_file.read
   end
 
   test :count do
@@ -122,6 +120,11 @@ class YouPlotSimpleTest < Test::Unit::TestCase
     assert_equal fixture('simple-count.txt'), @stderr_file.read
   end
 
+  test :c do
+    YouPlot::Command.new(['count']).run
+    assert_equal fixture('simple-count.txt'), @stderr_file.read
+  end
+
   test :plot_output_stdout do
     YouPlot::Command.new(['line', '-o']).run
     assert_equal '', @stderr_file.read