[rail_inspector] Extract Configuring::Document

In preparation for extracting more parsing behavior into this class and
some related classes. Parsing is currently distributed in the individual
checks, which makes them harder to test.

Author: skipkayhil

tools/rail_inspector/lib/rail_inspector/configuring.rb

@@ -3,6 +3,7 @@
 require "pathname"
 require_relative "./configuring/check/general_configuration"
 require_relative "./configuring/check/framework_defaults"
+require_relative "./configuring/document"
 
 module RailInspector
   class Configuring
@@ -43,29 +44,6 @@ def method_missing(name, ...)
       end
     end
 
-    class Doc
-      attr_accessor :general_config, :versioned_defaults
-
-      def initialize(content)
-        @before, @versioned_defaults, @general_config, @after =
-          content
-            .split("\n")
-            .slice_before do |line|
-              [
-                "### Versioned Default Values",
-                "### Rails General Configuration",
-                "### Configuring Assets"
-              ].include?(line)
-            end
-            .to_a
-      end
-
-      def to_s
-        (@before + @versioned_defaults + @general_config + @after).join("\n") +
-          "\n"
-      end
-    end
-
     attr_reader :errors, :files
 
     def initialize(rails_path)
@@ -88,7 +66,7 @@ def check
     end
 
     def doc
-      @doc ||= Configuring::Doc.new(files.doc_path.read)
+      @doc ||= Configuring::Document.parse(files.doc_path.read)
     end
 
     def rails_version

tools/rail_inspector/lib/rail_inspector/configuring/document.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+module RailInspector
+  class Configuring
+    class Document
+      class << self
+        def parse(text)
+          before, versioned_defaults, general_config, after =
+            text
+              .split("\n")
+              .slice_before do |line|
+                [
+                  "### Versioned Default Values",
+                  "### Rails General Configuration",
+                  "### Configuring Assets"
+                ].include?(line)
+              end
+              .to_a
+
+          new(before, versioned_defaults, general_config, after)
+        end
+      end
+
+      attr_accessor :general_config, :versioned_defaults
+
+      def initialize(before, versioned_defaults, general_config, after)
+        @before, @versioned_defaults, @general_config, @after =
+          before, versioned_defaults, general_config, after
+      end
+
+      def to_s
+        (@before + @versioned_defaults + @general_config + @after).join("\n") +
+          "\n"
+      end
+    end
+  end
+end