diff --git a/test/sub_function_codes/test_all_messages.py b/test/pdu/test_all_messages.py
similarity index 100%
rename from test/sub_function_codes/test_all_messages.py
rename to test/pdu/test_all_messages.py
diff --git a/test/sub_function_codes/test_bit_read_messages.py b/test/pdu/test_bit_read_messages.py
similarity index 99%
rename from test/sub_function_codes/test_bit_read_messages.py
rename to test/pdu/test_bit_read_messages.py
index 85f807e37a..ff892438e3 100644
--- a/test/sub_function_codes/test_bit_read_messages.py
+++ b/test/pdu/test_bit_read_messages.py
@@ -15,7 +15,7 @@
     ReadCoilsRequest,
     ReadDiscreteInputsRequest,
 )
-from test.conftest import MockContext
+from ..conftest import MockContext
 
 
 res = [True] * 21
diff --git a/test/sub_function_codes/test_bit_write_messages.py b/test/pdu/test_bit_write_messages.py
similarity index 99%
rename from test/sub_function_codes/test_bit_write_messages.py
rename to test/pdu/test_bit_write_messages.py
index 54cae8b41a..9d50307de2 100644
--- a/test/sub_function_codes/test_bit_write_messages.py
+++ b/test/pdu/test_bit_write_messages.py
@@ -13,7 +13,7 @@
     WriteSingleCoilRequest,
     WriteSingleCoilResponse,
 )
-from test.conftest import FakeList, MockContext
+from ..conftest import FakeList, MockContext
 
 
 # ---------------------------------------------------------------------------#
diff --git a/test/sub_function_codes/test_diag_messages.py b/test/pdu/test_diag_messages.py
similarity index 100%
rename from test/sub_function_codes/test_diag_messages.py
rename to test/pdu/test_diag_messages.py
diff --git a/test/sub_function_codes/test_mei_messages.py b/test/pdu/test_mei_messages.py
similarity index 100%
rename from test/sub_function_codes/test_mei_messages.py
rename to test/pdu/test_mei_messages.py
diff --git a/test/sub_function_codes/test_other_messages.py b/test/pdu/test_other_messages.py
similarity index 100%
rename from test/sub_function_codes/test_other_messages.py
rename to test/pdu/test_other_messages.py
diff --git a/test/sub_function_codes/test_register_read_messages.py b/test/pdu/test_register_read_messages.py
similarity index 99%
rename from test/sub_function_codes/test_register_read_messages.py
rename to test/pdu/test_register_read_messages.py
index ce5504e656..251d8dfe9c 100644
--- a/test/sub_function_codes/test_register_read_messages.py
+++ b/test/pdu/test_register_read_messages.py
@@ -10,7 +10,8 @@
     ReadWriteMultipleRegistersRequest,
     ReadWriteMultipleRegistersResponse,
 )
-from test.conftest import FakeList, MockContext
+
+from ..conftest import FakeList, MockContext
 
 
 TEST_MESSAGE = b"\x06\x00\x0a\x00\x0b\x00\x0c"
diff --git a/test/sub_function_codes/test_register_write_messages.py b/test/pdu/test_register_write_messages.py
similarity index 99%
rename from test/sub_function_codes/test_register_write_messages.py
rename to test/pdu/test_register_write_messages.py
index 8d702fb77b..313ef0350d 100644
--- a/test/sub_function_codes/test_register_write_messages.py
+++ b/test/pdu/test_register_write_messages.py
@@ -9,7 +9,7 @@
     WriteSingleRegisterRequest,
     WriteSingleRegisterResponse,
 )
-from test.conftest import MockContext, MockLastValuesContext
+from ..conftest import MockContext, MockLastValuesContext
 
 
 # ---------------------------------------------------------------------------#