Refactor command execution mocking helper to be more self-contained a…

…nd to be allowed per rspec context

spec/helpers/command_mocking_helpers.rb

@@ -1,34 +1,53 @@
-class CommandExecutionNotAllowed < ::StandardError
+module CommandExecutionMock
   COMMAND_EXECUTORS = %i(system exec spawn `).freeze
 
-  attr_reader :method_name, :args
-  def initialize(method_name, *args)
-    @method_name = method_name
-    @args        = args
+  def self.included(_base)
+    define_custom_matchers
+    disallow_command_execution
   end
 
-  def to_s
-    "Command execution is not allowed. Please stub the following call: #{method_name}(#{args.map(&:inspect).join(', ')})"
+  def define_custom_matchers
+    RSpec::Matchers.define :execute_nothing do
+      match do
+        COMMAND_EXECUTORS.each do |command_executor|
+          expect(Kernel).to_not receive(command_executor)
+        end
+      end
+    end
   end
-end
 
-RSpec.configure do |config|
-  config.before(:each) do
-    CommandExecutionNotAllowed::COMMAND_EXECUTORS.each do |command_executor|
-      allow_any_instance_of(Object).to receive(command_executor).and_wrap_original do |method, *args|
-        raise CommandExecutionNotAllowed.new(method.name, *args)
-      end
-      allow(Kernel).to receive(command_executor).and_wrap_original do |method, *args|
-        raise CommandExecutionNotAllowed.new(method.name, *args)
+  def disallow_command_execution
+    RSpec.configuration.before(:each) do |example|
+      unless example.metadata[:command_execution].to_s == 'allowed'
+        COMMAND_EXECUTORS.each do |executor|
+          stub_command_executor(executor)
+        end
       end
     end
   end
-end
 
-RSpec::Matchers.define :execute_nothing do |_expected|
-  match do |_actual|
-    CommandExecutionNotAllowed::COMMAND_EXECUTORS.each do |command_executor|
-      expect(Kernel).to_not receive(command_executor)
+  def stub_command_executor(executor)
+    allow_any_instance_of(Object).to receive(executor).and_wrap_original do |method, *args|
+      raise CommandExecutionNotAllowed.new(method.name, *args)
+    end
+    allow(Kernel).to receive(executor).and_wrap_original do |method, *args|
+      raise CommandExecutionNotAllowed.new(method.name, *args)
     end
   end
+
+  class CommandExecutionNotAllowed < ::StandardError
+    attr_reader :method_name, :args
+    def initialize(method_name, *args)
+      @method_name = method_name
+      @args        = args
+    end
+
+    def to_s
+      "Command execution is not allowed. Please stub the following call: #{method_name}(#{args.map(&:inspect).join(', ')})"
+    end
+  end
+end
+
+RSpec.configure do
+  include CommandExecutionMock
 end

spec/integration/unison_strategy_spec.rb

@@ -1,6 +1,6 @@
 require 'spec_helper'
 
-RSpec.describe 'Unison strategy' do
+RSpec.describe 'Unison strategy', command_execution: :allowed do
   include Rspec::Bash
 
   let(:bin) { 'bin/docker-sync' }