Push down details of strategy plugin loading

lib/mutant.rb

@@ -178,7 +178,6 @@ require 'mutant/mutator/node/splat'
 require 'mutant/mutator/node/resbody'
 require 'mutant/mutator/node/rescue'
 require 'mutant/mutator/node/match_current_line'
-require 'mutant/config'
 require 'mutant/loader'
 require 'mutant/context'
 require 'mutant/context/scope'
@@ -206,6 +205,7 @@ require 'mutant/test'
 require 'mutant/integration'
 require 'mutant/selector'
 require 'mutant/selector/expression'
+require 'mutant/config'
 require 'mutant/cli'
 require 'mutant/color'
 require 'mutant/diff'

lib/mutant/cli.rb

@@ -128,8 +128,7 @@ module Mutant
     # @api private
     #
     def setup_integration(name)
-      require "mutant/integration/#{name}"
-      update(integration: Integration.lookup(name))
+      update(integration: Integration.setup(name))
     rescue LoadError
       raise Error, "Could not load integration #{name.inspect} (you may want to try installing the gem mutant-#{name})"
     end

lib/mutant/integration.rb

@@ -6,6 +6,19 @@ module Mutant
 
     REGISTRY = {}
 
+    # Setup integration
+    #
+    # @param [String] name
+    #
+    # @return [Integration]
+    #
+    # @api private
+    #
+    def self.setup(name)
+      require "mutant/integration/#{name}"
+      lookup(name)
+    end
+
     # Lookup integration for name
     #
     # @param [String] name