SystemCommand wrapper

app/services/system_command.rb

@@ -0,0 +1,37 @@
+require "null_logger"
+
+class SystemCommand
+  attr_reader :program
+  attr_reader :args
+  attr_reader :logger
+
+  def initialize(program, args, logger: NullLogger.new)
+    @program = program
+    @args = Array.wrap(args)
+    @logger = logger
+  end
+
+  def execute
+    logger.log :before_command, syscmd
+
+    raw = `syscmd`
+
+    logger.log :after_command, raw
+
+    raw
+  end
+
+  def syscmd
+    escaped_args = args.map { |arg|
+      '"' + escape_arg(arg) + '"'
+    }
+
+    [program, escaped_args].join(" ")
+  end
+
+  private
+
+  def escape_arg(arg)
+    arg.to_s.gsub('"') { '\"' }
+  end
+end

test/services/system_command_test.rb

@@ -0,0 +1,21 @@
+require "test_helper"
+require "system_command"
+
+class SystemCommandTest < ActiveSupport::TestCase
+  test "should execute and log a command" do
+    mock_logger = Minitest::Mock.new
+    expected = 'whois "example.org"'
+
+    mock_logger.expect(:log, nil, [:before_command, expected])
+    mock_logger.expect(:log, nil, [:after_command, "my result"])
+
+    command = SystemCommand.new("whois", "example.org", logger: mock_logger)
+    assert_equal expected, command.syscmd
+
+    command.stub(:`, "my result") do
+      assert_equal "my result", command.execute
+    end
+
+    mock_logger.verify
+  end
+end