Change to optional warning display

lib/mutant/cli/command/environment.rb

@@ -13,6 +13,7 @@ class Environment < self
             add_runner_options
             add_integration_options
             add_matcher_options
+            add_reporter_options
           ].freeze
 
       private
@@ -126,6 +127,14 @@ def add_runner_options(parser)
             set(mutation: @config.mutation.with(timeout: Float(number)))
           end
         end
+
+        def add_reporter_options(parser)
+          parser.separator('Reporting:')
+
+          parser.on('--print-warnings', 'Print warnings') do
+            set(reporter: @config.reporter.with(print_warnings: true))
+          end
+        end
       end # Run
     end # Command
   end # CLI

lib/mutant/reporter/cli.rb

@@ -4,7 +4,7 @@ module Mutant
   class Reporter
     # Reporter that reports in human readable format
     class CLI < self
-      include Anima.new(:output, :format)
+      include Anima.new(:print_warnings, :output, :format)
 
       # Build reporter
       #
@@ -13,8 +13,9 @@ class CLI < self
       # @return [Reporter::CLI]
       def self.build(output)
         new(
-          format: Format::Progressive.new(tty: output.respond_to?(:tty?) && output.tty?),
-          output: output
+          format:         Format::Progressive.new(tty: output.respond_to?(:tty?) && output.tty?),
+          print_warnings: false,
+          output:         output
         )
       end
 
@@ -51,7 +52,7 @@ def delay
       #
       # @return [self]
       def warn(message)
-        output.puts(message)
+        output.puts(message) if print_warnings
         self
       end
 

spec/unit/mutant/cli_spec.rb

@@ -320,6 +320,10 @@ def self.main_body
                 --ignore-subject EXPRESSION  Ignore subjects that match EXPRESSION as prefix
                 --start-subject EXPRESSION   Start mutation testing at a specific subject
                 --since REVISION             Only select subjects touched since REVISION
+
+
+        Reporting:
+                --print-warnings             Print warnings
       MESSAGE
 
       {
@@ -370,6 +374,10 @@ def self.main_body
                 --ignore-subject EXPRESSION  Ignore subjects that match EXPRESSION as prefix
                 --start-subject EXPRESSION   Start mutation testing at a specific subject
                 --since REVISION             Only select subjects touched since REVISION
+
+
+        Reporting:
+                --print-warnings             Print warnings
       MESSAGE
 
       {
@@ -420,6 +428,10 @@ def self.main_body
                 --ignore-subject EXPRESSION  Ignore subjects that match EXPRESSION as prefix
                 --start-subject EXPRESSION   Start mutation testing at a specific subject
                 --since REVISION             Only select subjects touched since REVISION
+
+
+        Reporting:
+                --print-warnings             Print warnings
       MESSAGE
 
       {
@@ -864,6 +876,48 @@ def self.main_body
       end
     end
 
+    context 'environment subject list --print-warnings' do
+      include_context 'environment'
+
+      let(:arguments) { %w[environment subject list --print-warnings] }
+
+      let(:expected_exit) { true }
+
+      let(:expected_events) do
+        [
+          %i[
+            record
+            config
+          ],
+          [
+            :load_config,
+            {
+              cli_config: expected_cli_config.with(
+                reporter: expected_cli_config.reporter.with(print_warnings: true)
+              ),
+              world:      world
+            }.inspect
+          ],
+          [
+            :bootstrap,
+            Mutant::Env.empty(world, bootstrap_config).inspect
+          ],
+          [
+            :stdout,
+            :puts,
+            'Subjects in environment: 1'
+          ],
+          [
+            :stdout,
+            :puts,
+            'Object#send'
+          ]
+        ]
+      end
+
+      include_examples 'CLI run'
+    end
+
     context 'environment subject list' do
       include_context 'environment'
 

spec/unit/mutant/reporter/cli_spec.rb

@@ -3,9 +3,9 @@
 RSpec.describe Mutant::Reporter::CLI do
   setup_shared_context
 
-  let(:format) { described_class::Format::Progressive.new(tty: tty?) }
-  let(:object) { described_class.new(format: format, output: output) }
-  let(:tty?)   { false                                               }
+  let(:format) { described_class::Format::Progressive.new(tty: tty?)                        }
+  let(:object) { described_class.new(format: format, output: output, print_warnings: false) }
+  let(:tty?)   { false                                                                      }
 
   def contents
     output.rewind
@@ -26,18 +26,18 @@ def self.it_reports(expected_content)
       let(:tty?)   { true                            }
       let(:output) { instance_double(IO, tty?: true) }
 
-      it { should eql(described_class.new(format: format, output: output)) }
+      it { should eql(described_class.new(format: format, output: output, print_warnings: false)) }
     end
 
     context 'when output is not a tty' do
       context 'and does not respond to #tty?' do
         let(:output) { nil }
 
-        it { should eql(described_class.new(format: format, output: output)) }
+        it { should eql(described_class.new(format: format, output: output, print_warnings: false)) }
       end
 
       context 'and does respond to #tty?' do
-        it { should eql(described_class.new(format: format, output: output)) }
+        it { should eql(described_class.new(format: format, output: output, print_warnings: false)) }
       end
     end
   end
@@ -47,7 +47,15 @@ def self.it_reports(expected_content)
 
     let(:message) { 'message' }
 
-    it_reports("message\n")
+    context 'when print warnings is disabled' do
+      it_reports('')
+    end
+
+    context 'when print warnings is enabled' do
+      let(:object) { super().with(print_warnings: true) }
+
+      it_reports("message\n")
+    end
   end
 
   describe '#delay' do