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Project: Aruba 0.11.0

Publisher: Cucumber

Run commands in ruby process

Running a lot of scenarios where each scenario uses Aruba
to spawn a new ruby process can be time consuming.

Aruba lets you plug in your own process class that can
run a command in the same ruby process as Cucumber/Aruba.

We expect that the command supports the following API. It needs to accept:
argv, stdin, stdout, stderr and kernel on #initialize and it needs to have
an execute!-method.

module Cli
  module App
    class Runner
      def initialize(argv, stdin, stdout, stderr, kernel)
        \@argv   = argv
        \@stdin  = stdin
        \@stdout = stdout
        \@stderr = stderr
        \@kernel = kernel
      end

      def execute!
      end
    end
  end
end

The switch to the working directory takes place around the execute!-method.
If needed make sure, that you determine the current working directory within
code called by the execute!-method or just use Dir.getwd during "runtime"
and not during "loadtime", when the ruby-interpreter reads in you class
files.

WARNING: Using :in_process interactively is not supported

Background
Given
I use a fixture named "cli-app"
And
a file named "features/support/cli_app.rb" with: 
require 'cli/app/runner'
And
a file named "features/support/in_proccess.rb" with: 
require 'aruba/cucumber'

Before('@in-process') do
  aruba.config.command_launcher = :in_process
  aruba.config.main_class = Cli::App::Runner
end

After('@in-process') do
  aruba.config.command_launcher = :spawn
end
Scenarios
  1. Run custom code
  2. Mixing custom code and normal cli
  3. The current working directory is changed as well
  4. The PWD environment is changed to current working directory
  5. Set runner via "Aruba.process ="-method (deprecated)
  6. Set runner via "Aruba.process ="-method and use old class name Aruba::InProcess (deprecated)
  7. Use $stderr, $stdout and $stdin to access IO
  8. Use $kernel to use Kernel to capture exit code
  9. Using `:in_process` interactively is not supported
Run custom code
Given
a file named "lib/cli/app/runner.rb" with: 
module Cli
  module App
    class Runner
      def initialize(argv, stdin, stdout, stderr, kernel)
        @argv   = argv
        @stdin  = stdin
        @stdout = stdout
        @stderr = stderr
        @kernel = kernel
      end

      def execute!
        @stdout.puts(@argv.map(&:reverse).join(' '))
      end
    end
  end
end
And
a file named "features/in_process.feature" with: 
Feature: Run a command in process
  @in-process
  Scenario: Run command
    When I run reverse.rb Hello World
    Then the output should contain:
    """
    olleH dlroW
    """
When
I run cucumber
Then
the features should all pass
Mixing custom code and normal cli
Given
an executable named "bin/cli" with: 
#!/bin/bash
echo $*
And
a file named "lib/cli/app/runner.rb" with: 
module Cli
  module App
    class Runner
      def initialize(argv, stdin, stdout, stderr, kernel)
        @argv   = argv
        @stdin  = stdin
        @stdout = stdout
        @stderr = stderr
        @kernel = kernel
      end

      def execute!
        @stdout.puts(@argv.map(&:reverse).join(' '))
      end
    end
  end
end
And
a file named "features/in_process.feature" with: 
Feature: Run a command in process
  @in-process
  Scenario: Run command in process
    When I run reverse.rb Hello World
    Then the output should contain:
    """
    olleH dlroW
    """

  Scenario: Run command
    When I run cli Hello World
    Then the output should contain:
    """
    Hello World
    """
When
I run cucumber
Then
the features should all pass
The current working directory is changed as well
Given
a file named "lib/cli/app/runner.rb" with: 
module Cli
  module App
    class Runner
      def initialize(argv, stdin, stdout, stderr, kernel)
        @argv   = argv
        @stdin  = stdin
        @stdout = stdout
        @stderr = stderr
        @kernel = kernel
      end

      def execute!
        @stdout.puts("PWD-ENV is " + Dir.getwd)
      end
    end
  end
end
And
a file named "features/in_process.feature" with: 
Feature: Run a command in process
  @in-process
  Scenario: Run command
    When I run pwd.rb
    Then the output should match %r<PWD-ENV.*tmp/aruba>
When
I run cucumber
Then
the features should all pass
The PWD environment is changed to current working directory
Given
a file named "lib/cli/app/runner.rb" with: 
module Cli
  module App
    class Runner
      def initialize(argv, stdin, stdout, stderr, kernel)
        @argv   = argv
        @stdin  = stdin
        @stdout = stdout
        @stderr = stderr
        @kernel = kernel
      end

      def execute!
        @stdout.puts("PWD-ENV is " + ENV['PWD'])
      end
    end
  end
end
And
a file named "features/in_process.feature" with: 
Feature: Run a command in process
  @in-process
  Scenario: Run command
    When I run pwd.rb
    Then the output should match %r<PWD-ENV.*tmp/aruba>
When
I run cucumber
Then
the features should all pass
Set runner via "Aruba.process ="-method (deprecated)
Given
a file named "features/support/in_proccess.rb" with: 
require 'aruba/cucumber'
require 'aruba/processes/in_process'

Before('@in-process') do
  Aruba.process = Aruba::Processes::InProcess
  Aruba.process.main_class = Cli::App::Runner
end

After('@in-process') do
  Aruba.process = Aruba::Processes::SpawnProcess
end
Given
a file named "lib/cli/app/runner.rb" with: 
module Cli
  module App
    class Runner
      def initialize(argv, stdin, stdout, stderr, kernel)
        @argv   = argv
        @stdin  = stdin
        @stdout = stdout
        @stderr = stderr
        @kernel = kernel
      end

      def execute!
        @stdout.puts(@argv.map(&:reverse).join(' '))
      end
    end
  end
end
And
a file named "features/in_process.feature" with: 
Feature: Run a command in process
  @in-process
  Scenario: Run command
    When I run reverse.rb Hello World
    Then the output should contain:
    """
    olleH dlroW
    """
When
I run cucumber
Then
the features should all pass
Set runner via "Aruba.process ="-method and use old class name Aruba::InProcess (deprecated)
Given
a file named "features/support/in_proccess.rb" with: 
require 'aruba/cucumber'
require 'aruba/in_process'
require 'aruba/spawn_process'

Before('@in-process') do
  Aruba.process = Aruba::InProcess
  Aruba.process.main_class = Cli::App::Runner
end

After('@in-process') do
  Aruba.process = Aruba::SpawnProcess
end
Given
a file named "lib/cli/app/runner.rb" with: 
module Cli
  module App
    class Runner
      def initialize(argv, stdin, stdout, stderr, kernel)
        @argv   = argv
        @stdin  = stdin
        @stdout = stdout
        @stderr = stderr
        @kernel = kernel
      end

      def execute!
        @stdout.puts(@argv.map(&:reverse).join(' '))
      end
    end
  end
end
And
a file named "features/in_process.feature" with: 
Feature: Run a command in process
  @in-process
  Scenario: Run command
    When I run reverse.rb Hello World
    Then the output should contain:
    """
    olleH dlroW
    """
When
I run cucumber
Then
the features should all pass
Use $stderr, $stdout and $stdin to access IO

May may need/want to use the default STDERR, STDOUT, STDIN-constants
to access IO from within your script. Unfortunately this does not work with
the :in_process-command launcher. You need to use $stderr, $stdout
and $stdin instead.

For this example I chose thor to parse ARGV. Its .start-method accepts
an "Array" as ARGV and a "Hash" for some other options – .start <ARGV>, <OPTIONS>

Given
a file named "lib/cli/app/runner.rb" with: 
require 'cli/app/cli_parser'

module Cli
  module App
    class Runner
      def initialize(argv, stdin, stdout, stderr, kernel)
        @argv   = argv
        $kernel = kernel
        $stdin  = stdin
        $stdout = stdout
        $stderr = stderr
      end

      def execute!
        Cli::App::CliParser.start @argv
      end
    end
  end
end
And
a file named "lib/cli/app/cli_parser.rb" with: 
require 'thor'

module Cli
  module App
    class CliParser < Thor
      def self.exit_on_failure?
        true
      end

      desc 'do_it', 'Reverse input'
      def do_it(*args)
        $stderr.puts 'Hey ya, Hey ya, check, check, check'
        $stdout.puts(args.flatten.map(&:reverse).join(' '))
      end
    end
  end
end
And
a file named "features/in_process.feature" with: 
Feature: Run a command in process
  @in-process
  Scenario: Run command
    When I run reverse.rb do_it Hello World
    Then the stdout should contain:
    """
    olleH dlroW
    """
    And the stderr should contain:
    """
    Hey ya, Hey ya, check, check, check
    """
When
I run cucumber
Then
the features should all pass
Use $kernel to use Kernel to capture exit code

Ruby's Kernel-module provides some helper methods like exit.
Unfortunately running #exit with :in_process would make the whole ruby
interpreter exit. So you might want to use our FakeKernel-module module
instead which overwrites #exit. This will also make our tests for
checking the exit code work. This example also uses the thor-library.

Given
a file named "lib/cli/app/runner.rb" with: 
require 'cli/app/cli_parser'

module Cli
  module App
    class Runner
      def initialize(argv, stdin, stdout, stderr, kernel)
        @argv   = argv
        $kernel = kernel
        $stdin  = stdin
        $stdout = stdout
        $stderr = stderr
      end

      def execute!
        Cli::App::CliParser.start @argv
      end
    end
  end
end
And
a file named "lib/cli/app/cli_parser.rb" with: 
require 'thor'

module Cli
  module App
    class CliParser < Thor
      def self.exit_on_failure?
        true
      end

      desc 'do_it', 'Reverse input'
      def do_it(*args)
        $kernel.exit 5
      end
    end
  end
end
And
a file named "features/in_process.feature" with: 
Feature: Run a command in process
  @in-process
  Scenario: Run command
    When I run reverse.rb do_it
    Then the exit status should be 5
When
I run cucumber
Then
the features should all pass
Using `:in_process` interactively is not supported

Reading from STDIN blocks ruby from going on. But writing to STDIN - e.g.
type some letters on keyboard - can only appear later, but this point is
never reached, because ruby is blocked.

Given
the default aruba exit timeout is 5 seconds
And
a file named "lib/cli/app/runner.rb" with: 
module Cli
  module App
    class Runner
      def initialize(argv, stdin, stdout, stderr, kernel)
        @stdin  = stdin
      end

      def execute!
        while res = @stdin.gets.to_s.chomp
          break if res == 'quit'
          puts res.reverse
        end
      end
    end
  end
end
And
a file named "features/in_process.feature" with: 
Feature: Run a command in process
  @in-process
  Scenario: Run command
    Given the default aruba exit timeout is 2 seconds
    When I run reverse.rb do_it interactively
    When I type "hello"
    Then the output should contain:
    """
    hello
    """
When
I run cucumber
Then
the exit status should not be 0

Last published about 6 years ago by Max Meyer.