set text in post body to find in post rss spec

spec/views/posts/index.rss.haml_spec.rb

@@ -4,21 +4,21 @@ describe 'posts/index.rss.haml', type: "view" do
   before do
     controller.stub(:current_user) { nil }
     author = FactoryBot.create(:member)
-    @post1 = FactoryBot.create(:post, id: 1, author: author)
+    @post1 = FactoryBot.create(:post, id: 1, author: author, body: 'This is some text.')
     @post2 = FactoryBot.create(:post, id: 2, author: author)
     assign(:posts, [@post1, @post2])
     render
   end
 
   it 'shows RSS feed title' do
-    rendered.should have_content "Recent posts from all members"
+    expect(rendered).to have_content "Recent posts from all members"
   end
 
   it 'shows content of posts' do
-    rendered.should have_content "This is some text."
+    expect(rendered).to have_content "This is some text."
   end
 
   it 'gives the author in the item title' do
-    rendered.should have_content "#{@post1.subject} by #{@post1.author}"
+    expect(rendered).to have_content "#{@post1.subject} by #{@post1.author}"
   end
 end