Improve test suite performance with aruba wrapper:

* Implement ArubaProgramWrapper in cucumber env;
* Tag a few features to not use the wrapper as aruba doesn't support yet
  interactive testing with in process mode, and reported program name
  will not be the correct one;
* Assign required standard streams to CLI and Env classes.

features/cli_usage.feature

@@ -1,5 +1,6 @@
 Feature: CLI usage
 
+  @exec
   Scenario: prints the usage when an argument is missing
     When I run `producer`
     Then the exit status must be 64

features/recipe_ask.feature

@@ -1,5 +1,6 @@
 Feature: `ask' recipe keyword
 
+  @exec
   Scenario: prompts user with a list of choices on standard output
     Given a recipe with:
       """

features/support/env.rb

@@ -1,2 +1,34 @@
 require 'aruba/cucumber'
+require 'aruba/in_process'
 require 'cucumber/sshd/cucumber'
+require 'producer/core'
+
+
+class ArubaProgramWrapper
+  def initialize(argv, stdin = $stdin, stdout = $stdout, stderr = $stderr,
+    kernel = Kernel)
+    @argv   = argv
+    @stdin  = stdin
+    @stdout = stdout
+    @stderr = stderr
+    @kernel = kernel
+  end
+
+  def execute!
+    Producer::Core::CLI.run!(
+      @argv.dup, stdin: @stdin, stdout: @stdout, stderr: @stderr
+    )
+  rescue SystemExit => e
+    @kernel.exit(e.status)
+  end
+end
+
+
+Before('@exec') do
+  Aruba.process = Aruba::SpawnProcess
+end
+
+Before('~@exec') do
+  Aruba::InProcess.main_class = ArubaProgramWrapper
+  Aruba.process = Aruba::InProcess
+end

lib/producer/core/cli.rb

@@ -9,27 +9,28 @@ module Producer
       EX_SOFTWARE = 70
 
       class << self
-        def run!(arguments, output: $stderr)
-          cli = new(arguments)
+        def run!(arguments, stdin: $stdin, stdout: $stdout, stderr: $stderr)
+          cli = new(arguments, stdin: stdin, stdout: stdout, stderr: stderr)
           begin
             cli.parse_arguments!
             cli.run
           rescue ArgumentError
-            output.puts USAGE
+            stderr.puts USAGE
             exit EX_USAGE
           rescue RuntimeError => e
-            output.puts "#{e.class.name.split('::').last}: #{e.message}"
+            stderr.puts "#{e.class.name.split('::').last}: #{e.message}"
             exit EX_SOFTWARE
           end
         end
       end
 
-      attr_reader :arguments, :stdout, :env
+      attr_reader :arguments, :stdin, :stdout, :stderr, :env
 
-      def initialize(args, stdout: $stdout)
+      def initialize(args, stdin: $stdin, stdout: $stdout, stderr: $stderr)
         @arguments  = args
+        @stdin      = stdin
         @stdout     = stdout
-        @env        = Env.new(output: stdout)
+        @env        = Env.new(input: stdin, output: stdout)
       end
 
       def parse_arguments!

spec/producer/core/cli_spec.rb

@@ -8,19 +8,30 @@ module Producer::Core
     let(:recipe_file) { fixture_path_for 'recipes/some_recipe.rb' }
     let(:options)     { [] }
     let(:arguments)   { [*options, recipe_file] }
+    let(:stdin)       { StringIO.new}
     let(:stdout)      { StringIO.new }
+    let(:stderr)      { StringIO.new }
 
-    subject(:cli)     { CLI.new(arguments, stdout: stdout) }
+    subject(:cli)     { CLI.new(arguments, stdin: stdin, stdout: stdout) }
 
     describe '.run!' do
       let(:cli) { double('cli').as_null_object }
-      let(:output)    { StringIO.new }
-      subject(:run)   { described_class.run! arguments, output: output }
+
+      subject(:run) do
+        described_class.run! arguments,
+          stdin:  stdin,
+          stdout: stdout,
+          stderr: stderr
+      end
 
       before { allow(described_class).to receive(:new) { cli } }
 
-      it 'builds a new CLI with given arguments' do
-        expect(described_class).to receive(:new).with(arguments)
+      it 'builds a new CLI with given arguments and streams' do
+        expect(described_class).to receive(:new).with(arguments,
+          stdin:  stdin,
+          stdout: stdout,
+          stderr: stderr
+        )
         run
       end
 
@@ -46,9 +57,9 @@ module Producer::Core
           end
         end
 
-        it 'prints the usage' do
+        it 'prints the usage on the error stream' do
           trap_exit { run }
-          expect(output.string).to match /\AUsage: .+/
+          expect(stderr.string).to match /\AUsage: .+/
         end
       end
 
@@ -64,26 +75,24 @@ module Producer::Core
           end
         end
 
-        it 'prints exception name and message' do
+        it 'prints exception name and message and the error stream' do
           trap_exit { run }
-          expect(output.string).to match /\ARuntimeError: some message/
+          expect(stderr.string).to match /\ARuntimeError: some message/
         end
       end
     end
 
     describe '#initialize' do
-      it 'assigns the env with CLI output' do
-        expect(cli.env.output).to be stdout
-      end
-
-      context 'without options' do
       subject(:cli) { described_class.new(arguments) }
 
+      it 'assigns $stdin as the default standard input' do
+        expect(cli.stdin).to be $stdin
+      end
+
       it 'assigns $stdout as the default standard output' do
         expect(cli.stdout).to be $stdout
       end
     end
-    end
 
     describe '#arguments' do
       it 'returns the assigned arguments' do
@@ -101,6 +110,14 @@ module Producer::Core
       it 'returns the assigned env' do
         expect(cli.env).to be_an Env
       end
+
+      it 'assigns CLI stdin as the env input' do
+        expect(cli.env.input).to be stdin
+      end
+
+      it 'assigns CLI stdout as the env output' do
+        expect(cli.env.output).to be stdout
+      end
     end
 
     describe '#parse_arguments!' do