Fix tests

test/controllers/link_categories_controller_test.rb

@@ -3,8 +3,24 @@
 require "test_helper"
 
 class LinkCategoriesControllerTest < ActionDispatch::IntegrationTest
+  def login(email, password)
+    post "/login", params: { email: email, password: password }
+    assert_redirected_to "/"
+  end
+
+  def logout
+    post "/logout"
+    assert_redirected_to "/"
+  end
+
+  teardown do
+    logout
+  end
+
   setup do
     @link_category = link_categories(:one)
+    Account.create(email: "test@example.com", password: "password")
+    login("test@example.com", "password")
   end
 
   test "should get index" do