DEV: Slight refactor and add specs for composer peek (#142)

Followup cf9fd864dd

spec/system/composer_peek_spec.rb

@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+describe "Composer peek", type: :system do
+  fab!(:current_user) { Fabricate(:user, refresh_auto_groups: true) }
+  fab!(:topic) { Fabricate(:topic_with_op) }
+
+  let(:topic_page) { PageObjects::Pages::Topic.new }
+  let(:composer) { PageObjects::Components::Composer.new }
+
+  before do
+    upload_theme
+    sign_in(current_user)
+  end
+
+  it "does not show composer peek for small windows" do
+    topic_page.visit_topic(topic)
+    topic_page.click_footer_reply
+    expect(composer).to be_opened
+
+    resize_window(width: 600) { expect(page).to have_no_css(".peek-mode-toggle") }
+  end
+
+  it "turns on composer peek and remembers this preference on page load" do
+    topic_page.visit_topic(topic)
+    topic_page.click_footer_reply
+    expect(composer).to be_opened
+
+    resize_window(width: 1380) do
+      find(".peek-mode-toggle").click
+      expect(page).to have_css("body.peek-mode-active")
+
+      topic_page.visit_topic(topic)
+      topic_page.click_footer_reply
+      expect(composer).to be_opened
+      expect(page).to have_css("body.peek-mode-active")
+
+      find(".peek-mode-toggle").click
+      expect(page).to have_no_css("body.peek-mode-active")
+    end
+  end
+
+  it "hides the composer preview when toggling" do
+    topic_page.visit_topic(topic)
+    topic_page.click_footer_reply
+    expect(composer).to be_opened
+    expect(composer).to have_composer_preview
+
+    resize_window(width: 1380) do
+      find(".peek-mode-toggle").click
+      expect(page).to have_css("body.peek-mode-active")
+      expect(composer).to have_no_composer_preview
+    end
+  end
+end