Add regression test for custom trace class

Author: swalkinshaw

spec/graphql/tracing/trace_modes_spec.rb

@@ -248,4 +248,27 @@ def initialize(arg2:, **kwargs)
       assert ModeOptionsSchema.new_trace(mode: :extra)
     end
   end
+
+  module SomeTraceMod
+    def execute_query(query)
+      super
+    end
+  end
+
+  CustomTraceClass = Class.new(GraphQL::Tracing::Trace)
+
+  class BaseSchemaWithCustomTraceClass < GraphQL::Schema
+    use(GraphQL::Batch)
+    trace_class(CustomTraceClass)
+    trace_with(SomeTraceMod)
+  end
+
+  ChildSchema = Class.new(BaseSchemaWithCustomTraceClass)
+
+  describe "custom trace class supports trace module inheritance" do
+    it "inherits parent trace modules" do
+      assert_equal [GraphQL::Batch::SetupMultiplex::Trace, SomeTraceMod], ChildSchema.trace_modules_for(:default)
+      assert ChildSchema.new_trace.instance_variable_defined?(:@executor_class)
+    end
+  end
 end