Silence console output in tests

* Rspec callback that assigns IO objects to collect and silence all output of the SUT and Rake, driven by example metadata.
* Consistent cleanup in the test for print-config-variables option.
* Requiring necessary lib, which was missing in scm-resolver spec file.

spec/lib/capistrano/application_spec.rb

@@ -5,46 +5,40 @@ describe Capistrano::Application do
 
   it "provides a --format option which enables the choice of output formatting"
 
-  let(:help_output) do
-    out, _err = capture_io do
+  it "displays documentation URL as help banner", capture_io: true do
     flags "--help", "-h"
-    end
-    out
-  end
-
-  it "displays documentation URL as help banner" do
-    expect(help_output.lines.first).to match(/capistranorb.com/)
+    expect($stdout.string.each_line.first).to match(/capistranorb.com/)
   end
 
   %w(quiet silent verbose).each do |switch|
-    it "doesn't include --#{switch} in help" do
-      expect(help_output).not_to match(/--#{switch}/)
+    it "doesn't include --#{switch} in help", capture_io: true do
+      flags "--help", "-h"
+      expect($stdout.string).not_to match(/--#{switch}/)
     end
   end
 
-  it "overrides the rake method, but still prints the rake version" do
-    out, _err = capture_io do
+  it "overrides the rake method, but still prints the rake version", capture_io: true do
     flags "--version", "-V"
-    end
+    out = $stdout.string
     expect(out).to match(/\bCapistrano Version\b/)
     expect(out).to match(/\b#{Capistrano::VERSION}\b/)
     expect(out).to match(/\bRake Version\b/)
     expect(out).to match(/\b#{Rake::VERSION}\b/)
   end
 
-  it "overrides the rake method, and sets the sshkit_backend to SSHKit::Backend::Printer" do
-    capture_io do
+  it "overrides the rake method, and sets the sshkit_backend to SSHKit::Backend::Printer", capture_io: true do
     flags "--dry-run", "-n"
-    end
     sshkit_backend = Capistrano::Configuration.fetch(:sshkit_backend)
     expect(sshkit_backend).to eq(SSHKit::Backend::Printer)
   end
 
-  it "enables printing all config variables on command line parameter" do
-    capture_io do
+  it "enables printing all config variables on command line parameter", capture_io: true do
+    begin
       flags "--print-config-variables", "-p"
-    end
       expect(Capistrano::Configuration.fetch(:print_config_variables)).to be true
+    ensure
+      Capistrano::Configuration.reset!
+    end
   end
 
   def flags(*sets)
@@ -63,22 +57,4 @@ describe Capistrano::Application do
     subject.run
     subject.options
   end
-
-  def capture_io
-    require "stringio"
-
-    orig_stdout = $stdout
-    orig_stderr = $stderr
-    captured_stdout = StringIO.new
-    captured_stderr = StringIO.new
-    $stdout = captured_stdout
-    $stderr = captured_stderr
-
-    yield
-
-    return captured_stdout.string, captured_stderr.string
-  ensure
-    $stdout = orig_stdout
-    $stderr = orig_stderr
-  end
 end

spec/lib/capistrano/configuration/plugin_installer_spec.rb

@@ -49,7 +49,7 @@ module Capistrano
           expect(task.prerequisites).to eq([:example_prerequisite])
         end
 
-        it "sets defaults when load:defaults is invoked" do
+        it "sets defaults when load:defaults is invoked", capture_io: true do
           expect(fetch(:example_variable)).to be_nil
           invoke "load:defaults"
           expect(fetch(:example_variable)).to eq("foo")

spec/lib/capistrano/configuration/question_spec.rb

@@ -58,7 +58,7 @@ module Capistrano
           end
         end
 
-        context "tty unavailable" do
+        context "tty unavailable", capture_io: true do
           before do
             $stdin.expects(:gets).never
             $stdin.expects(:tty?).returns(false)

spec/lib/capistrano/configuration/scm_resolver_spec.rb

@@ -1,4 +1,5 @@
 require "spec_helper"
+require "capistrano/scm"
 
 module Capistrano
   class Configuration
@@ -24,12 +25,12 @@ module Capistrano
           expect { resolver.resolve }.to output(/will not load the git scm/i).to_stderr
         end
 
-        it "activates the git scm" do
+        it "activates the git scm", capture_io: true do
           resolver.resolve
           expect(Rake::Task["git:wrapper"]).not_to be_nil
         end
 
-        it "sets :scm to :git" do
+        it "sets :scm to :git", capture_io: true do
           resolver.resolve
           expect(fetch(:scm)).to eq(:git)
         end

spec/lib/capistrano/doctor/environment_doctor_spec.rb

@@ -29,7 +29,7 @@ module Capistrano
           Rake::Task.clear
         end
 
-        it "has an doctor:environment task that calls EnvironmentDoctor" do
+        it "has an doctor:environment task that calls EnvironmentDoctor", capture_io: true do
           EnvironmentDoctor.any_instance.expects(:call)
           Rake::Task["doctor:environment"].invoke
         end

spec/lib/capistrano/doctor/gems_doctor_spec.rb

@@ -53,7 +53,7 @@ module Capistrano
           Rake::Task.clear
         end
 
-        it "has an doctor:gems task that calls GemsDoctor" do
+        it "has an doctor:gems task that calls GemsDoctor", capture_io: true do
           GemsDoctor.any_instance.expects(:call)
           Rake::Task["doctor:gems"].invoke
         end

spec/lib/capistrano/doctor/servers_doctor_spec.rb

@@ -71,7 +71,7 @@ module Capistrano
           Rake::Task.clear
         end
 
-        it "has an doctor:servers task that calls ServersDoctor" do
+        it "has an doctor:servers task that calls ServersDoctor", capture_io: true do
           ServersDoctor.any_instance.expects(:call)
           Rake::Task["doctor:servers"].invoke
         end

spec/lib/capistrano/doctor/variables_doctor_spec.rb

@@ -74,7 +74,7 @@ module Capistrano
           Rake::Task.clear
         end
 
-        it "has an doctor:variables task that calls VariablesDoctor" do
+        it "has an doctor:variables task that calls VariablesDoctor", capture_io: true do
           VariablesDoctor.any_instance.expects(:call)
           Rake::Task["doctor:variables"].invoke
         end

spec/lib/capistrano/dsl/task_enhancements_spec.rb

@@ -35,7 +35,7 @@ module Capistrano
         end
       end
 
-      it "invokes in proper order if define after than before" do
+      it "invokes in proper order if define after than before", capture_io: true do
         task_enhancements.after("task", "after_task")
         task_enhancements.before("task", "before_task")
 
@@ -44,7 +44,7 @@ module Capistrano
         expect(order).to eq(%w(before_task task after_task))
       end
 
-      it "invokes in proper order if define before than after" do
+      it "invokes in proper order if define before than after", capture_io: true do
         task_enhancements.before("task", "before_task")
         task_enhancements.after("task", "after_task")
 
@@ -53,7 +53,7 @@ module Capistrano
         expect(order).to eq(%w(before_task task after_task))
       end
 
-      it "invokes in proper order when referring to as-yet undefined tasks" do
+      it "invokes in proper order when referring to as-yet undefined tasks", capture_io: true do
         task_enhancements.after("task", "not_loaded_task")
 
         Rake::Task.define_task("not_loaded_task") do
@@ -65,7 +65,7 @@ module Capistrano
         expect(order).to eq(%w(task not_loaded_task))
       end
 
-      it "invokes in proper order and with arguments and block" do
+      it "invokes in proper order and with arguments and block", capture_io: true do
         task_enhancements.after("task", "after_task_custom", :order) do |_t, _args|
           order.push "after_task"
         end
@@ -79,7 +79,7 @@ module Capistrano
         expect(order).to eq(%w(before_task task after_task))
       end
 
-      it "invokes using the correct namespace when defined within a namespace" do
+      it "invokes using the correct namespace when defined within a namespace", capture_io: true do
         Rake.application.in_namespace("namespace") do
           Rake::Task.define_task("task") do |t|
             order.push(t.name)
@@ -99,7 +99,7 @@ module Capistrano
         )
       end
 
-      it "raises a sensible error if the task isn't found" do
+      it "raises a sensible error if the task isn't found", capture_io: true do
         task_enhancements.after("task", "non_existent_task")
         expect { Rake::Task["task"].invoke order }.to raise_error(ArgumentError, 'Task "non_existent_task" not found')
       end

spec/lib/capistrano/dsl_spec.rb

@@ -60,7 +60,7 @@ module Capistrano
           end
         end
 
-        it "prints helpful message to stderr" do
+        it "prints helpful message to stderr", capture_io: true do
           expect do
             expect do
               task.invoke
@@ -72,7 +72,7 @@ module Capistrano
 
     describe "#invoke" do
       context "reinvoking" do
-        it "will not reenable invoking task" do
+        it "will not reenable invoking task", capture_io: true do
           counter = 0
 
           Rake::Task.define_task("A") do
@@ -85,7 +85,7 @@ module Capistrano
           end.to change { counter }.by(1)
         end
 
-        it "will print a message on stderr" do
+        it "will print a message on stderr", capture_io: true do
           Rake::Task.define_task("B")
 
           expect do
@@ -98,7 +98,7 @@ module Capistrano
 
     describe "#invoke!" do
       context "reinvoking" do
-        it "will reenable invoking task" do
+        it "will reenable invoking task", capture_io: true do
           counter = 0
 
           Rake::Task.define_task("C") do
@@ -111,7 +111,7 @@ module Capistrano
           end.to change { counter }.by(2)
         end
 
-        it "will not print a message on stderr" do
+        it "will not print a message on stderr", capture_io: true do
           Rake::Task.define_task("D")
 
           expect do

spec/lib/capistrano/plugin_spec.rb

@@ -62,14 +62,14 @@ module Capistrano
       dummy.expects(:set_defaults).never
     end
 
-    it "calls set_defaults during load:defaults" do
+    it "calls set_defaults during load:defaults", capture_io: true do
       dummy = DummyPlugin.new
       dummy.expects(:set_defaults).once
       install_plugin(dummy)
       Rake::Task["load:defaults"].invoke
     end
 
-    it "is able to load tasks from a .rake file" do
+    it "is able to load tasks from a .rake file", capture_io: true do
       install_plugin(ExternalTasksPlugin)
       Rake::Task["plugin_test"].invoke
       expect(fetch(:plugin_result)).to eq("hello")

spec/spec_helper.rb

@@ -13,4 +13,17 @@ RSpec.configure do |config|
   config.raise_errors_for_deprecations!
   config.mock_framework = :mocha
   config.order = "random"
+
+  config.around(:example, capture_io: true) do |example|
+    begin
+      Rake.application.options.trace_output = StringIO.new
+      $stdout = StringIO.new
+      $stderr = StringIO.new
+      example.run
+    ensure
+      Rake.application.options.trace_output = STDERR
+      $stdout = STDOUT
+      $stderr = STDERR
+    end
+  end
 end