Move tests related with attached documents from documentable shared specs to nested documentable file

Note that we moved some system tests to component tests, since they don't involve user interaction and can
be fully covered at the component level.

spec/components/documents/document_component_spec.rb

@@ -0,0 +1,37 @@
+require "rails_helper"
+
+describe Documents::DocumentComponent do
+  let(:user) { create(:user) }
+  let(:proposal) { create(:proposal, author: user) }
+  let(:document) { create(:document, documentable: proposal) }
+  let(:component) { Documents::DocumentComponent.new(document, show_destroy_link: true) }
+
+  describe "Delete document button" do
+    it "is not shown when no user is logged in" do
+      render_inline component
+
+      expect(page).not_to have_button "Delete document"
+    end
+
+    it "is shown when the author is logged in" do
+      sign_in(user)
+      render_inline component
+
+      expect(page).to have_button "Delete document"
+    end
+
+    it "is not shown when an administrator that isn't the author is logged in", :admin do
+      render_inline component
+
+      expect(page).not_to have_button "Delete document"
+    end
+
+    it "is not shown when a user that isn't the author is logged in" do
+      login_as(create(:user))
+
+      render_inline component
+
+      expect(page).not_to have_button "Delete document"
+    end
+  end
+end