diff --git a/code/capture3_with_timeout.rb b/code/capture3_with_timeout.rb
index f09baf41..141e887b 100644
--- a/code/capture3_with_timeout.rb
+++ b/code/capture3_with_timeout.rb
@@ -14,7 +14,7 @@ def initialize(context)
   def run(command, max_seconds, tgz_in)
     result = { timed_out: false }
     pid = nil
-    waiter = OpenStruct.new(value: nil)
+    waiter = Struct.new(:value).new(nil)
     pipes = make_binary_pipes
     stdout_reader = threaded('stdout-reader') { pipes[:stdout].in.read }
     stderr_reader = threaded('stderr-reader') { pipes[:stderr].in.read }
diff --git a/test/client/json_responder_test.rb b/test/client/json_responder_test.rb
index 4dc95de8..45d103e2 100644
--- a/test/client/json_responder_test.rb
+++ b/test/client/json_responder_test.rb
@@ -92,11 +92,11 @@ def initialize(body)
     end
 
     def get(_path, _args)
-      OpenStruct.new(body: @body)
+      Struct.new(:body).new(@body)
     end
 
     def post(_path, _args)
-      OpenStruct.new(body: @body)
+      Struct.new(:body).new(@body)
     end
   end
 
diff --git a/test/doubles/rack_request_stub.rb b/test/doubles/rack_request_stub.rb
index 42d83c55..574300ba 100644
--- a/test/doubles/rack_request_stub.rb
+++ b/test/doubles/rack_request_stub.rb
@@ -7,7 +7,7 @@ def initialize(env)
   end
 
   def body
-    OpenStruct.new(read: @env[:body])
+    Struct.new(:read).new(@env[:body])
   end
 
   def path_info