Extract methods in votes components

This way we can make the view code a bit easier to read.

We're also changing the order of the conditions a little bit so we only
check for the presence of a current user once.

To make sure we aren't breaking anything with these changes, we're
adding some tests. We're also replacing one system test checking content
with a component test, since component tests are much faster.

spec/components/proposals/votes_component_spec.rb

@@ -0,0 +1,77 @@
+require "rails_helper"
+
+describe Proposals::VotesComponent do
+  let(:proposal) { create(:proposal, title: "Create a monthly transport ticket") }
+  let(:component) { Proposals::VotesComponent.new(proposal) }
+
+  describe "support proposal link" do
+    it "is shown as plain text to unverified users" do
+      sign_in(create(:user))
+
+      render_inline component
+
+      expect(page).to have_content "Support"
+      expect(page).not_to have_link "Support"
+    end
+
+    it "is shown to verified users" do
+      sign_in(create(:user, :level_two))
+
+      render_inline component
+
+      expect(page).to have_link count: 1
+      expect(page).to have_link "Support", title: "Support this proposal"
+      expect(page).not_to have_content "You have already supported this proposal. Share it!"
+    end
+
+    it "is replaced with a success message when the proposal is already supported" do
+      sign_in(create(:user, :level_two, votables: [proposal]))
+
+      render_inline component
+
+      expect(page).to have_content "You have already supported this proposal. Share it!"
+      expect(page).not_to have_link "Support"
+    end
+  end
+
+  describe "participation not allowed" do
+    it "asks anonymous users to sign in or sign up" do
+      render_inline component
+
+      expect(page).to have_link "sign in", visible: :hidden
+      expect(page).to have_link "sign up", visible: :hidden
+    end
+
+    it "says voting is not allowed to organizations" do
+      sign_in(create(:organization, user: create(:user, :level_two)).user)
+
+      render_inline component
+
+      expect(page).to have_content "Organizations are not permitted to vote"
+      expect(page).not_to have_link "sign in", visible: :all
+      expect(page).not_to have_link "sign up", visible: :all
+    end
+
+    it "says only verified users can vote to unverified users" do
+      sign_in(create(:user))
+
+      render_inline component
+
+      expect(page).to have_content "Only verified users can vote on proposals"
+      expect(page).to have_link "verify your account", visible: :hidden
+      expect(page).not_to have_link "sign in", visible: :all
+      expect(page).not_to have_link "sign up", visible: :all
+    end
+
+    it "is not rendered for verified users" do
+      sign_in(create(:user, :level_two))
+
+      render_inline component
+
+      expect(page).not_to have_css ".participation-not-allowed"
+      expect(page).not_to have_link "verify your account", visible: :all
+      expect(page).not_to have_link "sign in", visible: :all
+      expect(page).not_to have_link "sign up", visible: :all
+    end
+  end
+end