Colorize output with --color

Displays all violation in red

lib/cane/cli/parser.rb

@@ -118,6 +118,9 @@ def add_cane_options
           "Use all processors. Slower on small projects, faster on large.",
             cast: ->(x) { x }
 
+        add_option %w(--color),
+          "Colorize output", default: false
+
         parser.separator ""
       end
 

lib/cane/runner.rb

@@ -19,7 +19,7 @@ def initialize(spec)
     end
 
     def run
-      outputter.print formatter.new(violations)
+      outputter.print formatter.new(violations, opts)
 
       violations.length <= opts.fetch(:max_violations)
     end

lib/cane/violation_formatter.rb

@@ -6,24 +6,28 @@ module Cane
   # Computes a string to be displayed as output from an array of violations
   # computed by the checks.
   class ViolationFormatter
-    attr_reader :violations
+    attr_reader :violations, :options
 
-    def initialize(violations)
+    def initialize(violations, options = {})
       @violations = violations.map do |v|
         v.merge(file_and_line: v[:line] ?
           "%s:%i" % v.values_at(:file, :line) :
           v[:file]
         )
       end
+
+      @options = options
     end
 
     def to_s
       return "" if violations.empty?
 
-      violations.group_by {|x| x[:description] }.map do |d, vs|
+      string = violations.group_by {|x| x[:description] }.map do |d, vs|
         format_group_header(d, vs) +
           format_violations(vs)
       end.join("\n") + "\n\n" + totals + "\n\n"
+
+      colorize(string)
     end
 
     protected
@@ -54,6 +58,12 @@ def format_violation(v, column_widths)
       }.join('  ').strip
     end
 
+    def colorize(string)
+      return string unless options[:color]
+
+      "\e[31m#{string}\e[0m"
+    end
+
     def totals
       "Total Violations: #{violations.length}"
     end

spec/cane_spec.rb

@@ -69,6 +69,12 @@ def violations
     Cane.task_runner(parallel: true).should == Parallel
   end
 
+  it 'colorizes output' do
+    output, exitstatus = run("--color --abc-max 0")
+
+    output.should include("\e[31m")
+  end
+
   after do
     if Object.const_defined?(class_name)
       Object.send(:remove_const, class_name)

spec/violation_formatter_spec.rb

@@ -18,4 +18,15 @@ def violation(description)
     result = described_class.new(violations).to_s
     result.should include("Total Violations: 2")
   end
+
+  it 'does not colorize output by default' do
+    result = described_class.new([violation("FAIL")]).to_s
+    result.should_not include("\e[31m")
+  end
+
+  it 'colorizes output when passed color: true' do
+    result = described_class.new([violation("FAIL")], color: true).to_s
+    result.should include("\e[31m")
+    result.should include("\e[0m")
+  end
 end