Prohibit duplicate memberships

test/controllers/memberships/unlink_controller_test.rb

@@ -0,0 +1,30 @@
+require "test_helper"
+
+class Memberships::UnlinkControllerTest < ActionDispatch::IntegrationTest
+  test "show" do
+    untenanted do
+      sign_in_as :kevin
+
+      membership = memberships(:kevin_in_37signals)
+      signed_id = membership.signed_id(purpose: :unlinking)
+
+      get unlink_membership_path(membership_id: signed_id)
+      assert_response :success
+    end
+  end
+
+  test "create" do
+    untenanted do
+      sign_in_as :kevin
+
+      membership = memberships(:kevin_in_37signals)
+      signed_id = membership.signed_id(purpose: :unlinking)
+
+      assert_difference -> { Membership.count }, -1 do
+        post unlink_membership_path(membership_id: signed_id)
+      end
+
+      assert_redirected_to session_menu_path
+    end
+  end
+end