Remove instance variables in generated specs

RSpec/InstanceVariable rule of rubocop-rspec gem prefers
no instance variable usages in specs by default, at least v2.10.0

Author: nekketsuuu

lib/generators/rspec/scaffold/templates/edit_spec.rb

@@ -2,18 +2,22 @@
 
 <% output_attributes = attributes.reject{|attribute| [:datetime, :timestamp, :time, :date].index(attribute.type) } -%>
 RSpec.describe "<%= ns_table_name %>/edit", <%= type_metatag(:view) %> do
-  before(:each) do
-    @<%= ns_file_name %> = assign(:<%= ns_file_name %>, <%= class_name %>.create!(<%= '))' if output_attributes.empty? %>
+  let(:<%= ns_file_name %>) {
+    <%= class_name %>.create!(<%= ')' if output_attributes.empty? %>
 <% output_attributes.each_with_index do |attribute, attribute_index| -%>
       <%= attribute.name %>: <%= attribute.default.inspect %><%= attribute_index == output_attributes.length - 1 ? '' : ','%>
 <% end -%>
-<%= output_attributes.empty? ? "" : "    ))\n" -%>
+<%= "    )\n" unless output_attributes.empty? -%>
+  }
+
+  before(:each) do
+    assign(:<%= ns_file_name %>, <%= ns_file_name %>)
   end
 
   it "renders the edit <%= ns_file_name %> form" do
     render
 
-    assert_select "form[action=?][method=?]", <%= ns_file_name %>_path(@<%= ns_file_name %>), "post" do
+    assert_select "form[action=?][method=?]", <%= ns_file_name %>_path(<%= ns_file_name %>), "post" do
 <% for attribute in output_attributes -%>
       <%- name = attribute.respond_to?(:column_name) ? attribute.column_name : attribute.name %>
       assert_select "<%= attribute.input_type -%>[name=?]", "<%= ns_file_name %>[<%= name %>]"

lib/generators/rspec/scaffold/templates/show_spec.rb

@@ -3,7 +3,7 @@
 <% output_attributes = attributes.reject{|attribute| [:datetime, :timestamp, :time, :date].index(attribute.type) } -%>
 RSpec.describe "<%= ns_table_name %>/show", <%= type_metatag(:view) %> do
   before(:each) do
-    @<%= ns_file_name %> = assign(:<%= ns_file_name %>, <%= class_name %>.create!(<%= '))' if output_attributes.empty? %>
+    assign(:<%= ns_file_name %>, <%= class_name %>.create!(<%= '))' if output_attributes.empty? %>
 <% output_attributes.each_with_index do |attribute, attribute_index| -%>
       <%= attribute.name %>: <%= value_for(attribute) %><%= attribute_index == output_attributes.length - 1 ? '' : ','%>
 <% end -%>