2 files changed, 10 insertions, 7 deletions
diff --git a/actionpack/test/dispatch/routing_test.rb b/actionpack/test/dispatch/routing_test.rb
index 6ba52e37b6..9b6e060955 100644
--- a/actionpack/test/dispatch/routing_test.rb
+++ b/actionpack/test/dispatch/routing_test.rb
@@ -4684,22 +4684,25 @@ class TestUrlGenerationErrors < ActionDispatch::IntegrationTest
 
   include Routes.url_helpers
 
-  test "url helpers raise a helpful error message when generation fails" do
+  test "url helpers raise a 'missing keys' error for a nil param with optimized helpers" do
     url, missing = { action: "show", controller: "products", id: nil }, [:id]
-    message = "No route matches #{url.inspect} missing required keys: #{missing.inspect}"
+    message = "No route matches #{url.inspect}, missing required keys: #{missing.inspect}"
 
-    # Optimized url helper
     error = assert_raises(ActionController::UrlGenerationError) { product_path(nil) }
     assert_equal message, error.message
+  end
+
+  test "url helpers raise a 'constraint failure' error for a nil param with non-optimized helpers" do
+    url, missing = { action: "show", controller: "products", id: nil }, [:id]
+    message = "No route matches #{url.inspect}, possible unmatched constraints: #{missing.inspect}"
 
-    # Non-optimized url helper
     error = assert_raises(ActionController::UrlGenerationError, message) { product_path(id: nil) }
     assert_equal message, error.message
   end
 
-  test "url helpers raise message with mixed parameters when generation fails " do
+  test "url helpers raise message with mixed parameters when generation fails" do
     url, missing = { action: "show", controller: "products", id: nil, "id"=>"url-tested" }, [:id]
-    message = "No route matches #{url.inspect} missing required keys: #{missing.inspect}"
+    message = "No route matches #{url.inspect}, possible unmatched constraints: #{missing.inspect}"
 
     # Optimized url helper
     error = assert_raises(ActionController::UrlGenerationError) { product_path(nil, "id"=>"url-tested") }
diff --git a/actionpack/test/journey/router_test.rb b/actionpack/test/journey/router_test.rb
index 2b99637f56..7b5916eb72 100644
--- a/actionpack/test/journey/router_test.rb
+++ b/actionpack/test/journey/router_test.rb
@@ -297,7 +297,7 @@ module ActionDispatch
         }
         request_parameters = primarty_parameters.merge(redirection_parameters).merge(missing_parameters)
 
-        message = "No route matches #{Hash[request_parameters.sort_by { |k,v|k.to_s }].inspect} missing required keys: #{[missing_key.to_sym].inspect}"
+        message = "No route matches #{Hash[request_parameters.sort_by { |k,v|k.to_s }].inspect}, missing required keys: #{[missing_key.to_sym].inspect}"
 
         error = assert_raises(ActionController::UrlGenerationError) do
           @formatter.generate(