Hide test_unit generators when using other test framework

Author: eval

railties/lib/rails/generators.rb

@@ -157,7 +157,9 @@ def hidden_namespaces
             "action_text:install",
             "action_mailbox:install",
             "devcontainer"
-          ]
+          ].tap do |h|
+            h << "test_unit" if test.to_s != "test_unit"
+          end
         end
       end
 

railties/test/application/generators_test.rb

@@ -203,6 +203,15 @@ def check_expected
       end
     end
 
+    test "help hides test_unit when using another test_framework" do
+      add_to_config <<-RUBY
+        config.generators.test_framework :rspec
+      RUBY
+
+      output = rails("generate", "--help")
+      assert_no_match "test_unit", output
+    end
+
     test "skip collision check" do
       rails("generate", "model", "post", "title:string")