Add silent option to suppress console output

Usage: SimpleCov::Formatter::HTMLFormatter.new(silent: true)

Closes #116.

Author: sferik

lib/simplecov-html.rb

@@ -22,12 +22,13 @@ class HTMLFormatter
         ".css" => "text/css",
       }.freeze
 
-      def initialize
+      def initialize(silent: false)
         @branch_coverage = SimpleCov.branch_coverage?
         @method_coverage = SimpleCov.method_coverage?
         @templates = {}
         @inline_assets = !ENV["SIMPLECOV_INLINE_ASSETS"].nil?
         @public_assets_dir = File.join(File.dirname(__FILE__), "../public/")
+        @silent = silent
       end
 
       def format(result)
@@ -40,7 +41,7 @@ def format(result)
         File.open(File.join(output_path, "index.html"), "wb") do |file|
           file.puts template("layout").result(binding)
         end
-        puts output_message(result)
+        puts output_message(result) unless @silent
       end
 
     private

test/test_simple_cov-html.rb

@@ -89,6 +89,14 @@ def bad_template.result(_binding)
     assert_match(/Encoding problems with file/, output)
   end
 
+  def test_silenced_output
+    result = SimpleCov::Result.new({fixtures_path.join("sample.rb").to_s => CoverageFixtures::SAMPLE_RB})
+    formatter = SimpleCov::Formatter::HTMLFormatter.new(silent: true)
+    stdout, = capture_io { formatter.format(result) }
+
+    assert_empty stdout
+  end
+
   def test_strength_css_classes
     formatter = SimpleCov::Formatter::HTMLFormatter.new