Set the current page as active

This only has an affect on pages using the design system (which currently, is just the what's new page).

Adds some tests around the navigation links.

app/helpers/navigation_helper.rb

@@ -1,8 +1,8 @@
 module NavigationHelper
   def navigation_links_internal
     [
-      { text: "Manuals", href: manuals_path },
-      { text: "What's new", href: whats_new_path },
+      { text: "Manuals", href: manuals_path, active: request.path == manuals_path },
+      { text: "What's new", href: whats_new_path, active: request.path == whats_new_path },
     ]
   end
 

spec/helpers/navigation_helper_spec.rb

@@ -0,0 +1,42 @@
+require "spec_helper"
+describe NavigationHelper, type: :helper do
+  describe "#navigation_links_internal" do
+    it "returns a list of internal links" do
+      expect(navigation_links_internal).to be_an_instance_of(Array)
+    end
+
+    it "includes a link to manuals" do
+      expect(navigation_links_internal).to include(a_hash_including(text: "Manuals", href: manuals_path))
+    end
+
+    it "includes a link to what's new" do
+      expect(navigation_links_internal).to include(a_hash_including(text: "What's new", href: whats_new_path))
+    end
+
+    it "sets the link to the current page as active" do
+      request.path = manuals_path
+      expect(navigation_links_internal).to include(a_hash_including(text: "Manuals", active: true))
+      expect(navigation_links_internal).to include(a_hash_including(text: "What's new", active: false))
+    end
+  end
+
+  describe "#navigation_links_auth" do
+    let(:current_user) { User.create!(name: "John Doe") }
+
+    it "returns a list of auth links" do
+      expect(navigation_links_auth).to be_an_instance_of(Array)
+    end
+
+    it "includes a link to the user's profile" do
+      expect(navigation_links_auth).to include(
+        a_hash_including(text: "John Doe", href: Plek.external_url_for("signon")),
+      )
+    end
+
+    it "includes a link to sign out" do
+      expect(navigation_links_auth).to include(
+        a_hash_including(text: "Log out", href: gds_sign_out_path),
+      )
+    end
+  end
+end