Add mutant environment irb subcommand

Changelog.md

@@ -1,3 +1,10 @@
+# v0.10.35 2021-10-17
+
+* [#1269](https://github.com/mbj/mutant/pull/1269)
+  Add `mutant environment irb` command. Starts an IRB session for the
+  configured mutant environment. Very useful for iterating on environment
+  setup issues.
+
 # v0.10.34 2021-08-30
 
 * [#1252](https://github.com/mbj/mutant/pull/1252)

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    mutant (0.10.34)
+    mutant (0.10.35)
       diff-lcs (~> 1.3)
       parser (~> 3.0.0)
       regexp_parser (~> 2.0, >= 2.0.3)
@@ -69,4 +69,4 @@ DEPENDENCIES
   rubocop (~> 1.7)
 
 BUNDLED WITH
-   2.2.25
+   2.2.29

lib/mutant.rb

@@ -4,6 +4,7 @@
 require 'diff/lcs/hunk'
 require 'digest/sha1'
 require 'etc'
+require 'irb'
 require 'json'
 require 'open3'
 require 'optparse'
@@ -194,6 +195,7 @@ module Mutant
 require 'mutant/cli/command'
 require 'mutant/cli/command/subscription'
 require 'mutant/cli/command/environment'
+require 'mutant/cli/command/environment/irb'
 require 'mutant/cli/command/environment/run'
 require 'mutant/cli/command/environment/show'
 require 'mutant/cli/command/environment/subject'

lib/mutant/cli/command/environment/irb.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+module Mutant
+  module CLI
+    class Command
+      class Environment
+        class IRB < self
+          NAME              = 'irb'
+          SHORT_DESCRIPTION = 'Run irb with mutant environment loaded'
+          SUBCOMMANDS       = EMPTY_ARRAY
+
+        private
+
+          def action
+            bootstrap.fmap { TOPLEVEL_BINDING.irb }
+          end
+        end # IRB
+      end # Environment
+    end # Command
+  end # CLI
+end # Mutant

lib/mutant/cli/command/root.rb

@@ -4,7 +4,7 @@ module Mutant
   module CLI
     class Command
       class Environment < self
-        SUBCOMMANDS = [Environment::Subject, Environment::Show, Environment::Test].freeze
+        SUBCOMMANDS = [Environment::Subject, Environment::Show, Environment::IRB, Environment::Test].freeze
       end # Environment
 
       class Root < self

lib/mutant/version.rb

@@ -2,5 +2,5 @@
 
 module Mutant
   # Current mutant version
-  VERSION = '0.10.34'
+  VERSION = '0.10.35'
 end # Mutant

spec/unit/mutant/cli_spec.rb

@@ -557,6 +557,39 @@ def self.main_body
       end
     end
 
+    context 'environment irb' do
+      include_context 'environment'
+
+      before do
+        allow(TOPLEVEL_BINDING).to receive(:irb) do
+          events << :irb_execution
+        end
+      end
+
+      let(:arguments) { %w[environment irb] }
+
+      context 'without additional arguments' do
+        let(:expected_exit) { true }
+
+        let(:expected_events) do
+          [
+            [
+              :load_config_file,
+              world
+            ],
+            [
+              :bootstrap,
+              world,
+              bootstrap_config.inspect
+            ],
+            :irb_execution
+          ]
+        end
+
+        include_examples 'CLI run'
+      end
+    end
+
     context 'environment test list' do
       include_context 'environment'