Let's see what happens.

Makefile

@@ -14,7 +14,7 @@ services-down:
 
 test-python:
 	@echo "Running Python tests"
-	wait-for-it --service httpbin.local:443 --service localhost:6379 --timeout 5 -- pytest tests/ || exit 1
+	wait-for-it --service httpbin.local:443 --service localhost:6379 --timeout 5 -- pytest --doctest-modules || exit 1
 	@echo ""
 
 lint-python:

mocket/mocket.py

@@ -22,14 +22,7 @@
     urllib3_wrap_socket = None
 
 from .compat import basestring, byte_type, decode_from_bytes, encode_to_bytes, text_type
-from .utils import (
-    SSL_PROTOCOL,
-    MocketMode,
-    MocketSocketCore,
-    get_mocketize,
-    hexdump,
-    hexload,
-)
+from .utils import SSL_PROTOCOL, MocketMode, get_mocketize, hexdump, hexload
 
 xxh32 = None
 try:
@@ -176,6 +169,10 @@ class MocketSocket:
     _mode = None
     _bufsize = None
     _secure_socket = False
+    _did_handshake = False
+    _sent_non_empty_bytes = False
+    r_fd = None
+    w_fd = None
 
     def __init__(
         self, family=socket.AF_INET, type=socket.SOCK_STREAM, proto=0, **kwargs
@@ -187,8 +184,6 @@ def __init__(
         self.type = int(type)
         self.proto = int(proto)
         self._truesocket_recording_dir = None
-        self._did_handshake = False
-        self._sent_non_empty_bytes = False
         self.kwargs = kwargs
 
     def __str__(self):
@@ -205,7 +200,7 @@ def __exit__(self, exc_type, exc_val, exc_tb):
     @property
     def fd(self):
         if self._fd is None:
-            self._fd = MocketSocketCore()
+            self._fd = io.BytesIO()
         return self._fd
 
     def gettimeout(self):
@@ -264,12 +259,11 @@ def unwrap(self):
     def write(self, data):
         return self.send(encode_to_bytes(data))
 
-    @staticmethod
-    def fileno():
-        if Mocket.r_fd is not None:
-            return Mocket.r_fd
-        Mocket.r_fd, Mocket.w_fd = os.pipe()
-        return Mocket.r_fd
+    def fileno(self):
+        if self.r_fd:
+            return self.r_fd
+        self.r_fd, self.w_fd = os.pipe()
+        return self.r_fd
 
     def connect(self, address):
         self._address = self._host, self._port = address
@@ -297,6 +291,8 @@ def sendall(self, data, entry=None, *args, **kwargs):
             response = self.true_sendall(data, *args, **kwargs)
 
         if response is not None:
+            if self.r_fd and self.w_fd:
+                os.write(self.w_fd, response)
             self.fd.seek(0)
             self.fd.write(response)
             self.fd.truncate()
@@ -320,8 +316,8 @@ def recv_into(self, buffer, buffersize=None, flags=None):
         return len(data)
 
     def recv(self, buffersize, flags=None):
-        if Mocket.r_fd and Mocket.w_fd:
-            return os.read(Mocket.r_fd, buffersize)
+        if self.r_fd and self.w_fd:
+            return os.read(self.r_fd, buffersize)
         data = self.read(buffersize)
         if data:
             return data
@@ -438,9 +434,13 @@ def close(self):
         if self.true_socket and not self.true_socket._closed:
             self.true_socket.close()
         self._fd = None
+        if self.r_fd:
+            os.close(self.r_fd)
+        if self.w_fd:
+            os.close(self.w_fd)
 
     def __getattr__(self, name):
-        """Do nothing catchall function, for methods like close() and shutdown()"""
+        """Do nothing catchall function, for methods like shutdown()"""
 
         def do_nothing(*args, **kwargs):
             pass
@@ -454,8 +454,6 @@ class Mocket:
     _requests = []
     _namespace = text_type(id(_entries))
     _truesocket_recording_dir = None
-    r_fd = None
-    w_fd = None
 
     @classmethod
     def register(cls, *entries):
@@ -477,12 +475,6 @@ def collect(cls, data):
 
     @classmethod
     def reset(cls):
-        if cls.r_fd is not None:
-            os.close(cls.r_fd)
-            cls.r_fd = None
-        if cls.w_fd is not None:
-            os.close(cls.w_fd)
-            cls.w_fd = None
         cls._entries = collections.defaultdict(list)
         cls._requests = []
 

mocket/utils.py

@@ -1,6 +1,4 @@
 import binascii
-import io
-import os
 import ssl
 from typing import Tuple, Union
 
@@ -10,16 +8,6 @@
 SSL_PROTOCOL = ssl.PROTOCOL_TLSv1_2
 
 
-class MocketSocketCore(io.BytesIO):
-    def write(self, content):
-        super(MocketSocketCore, self).write(content)
-
-        from mocket import Mocket
-
-        if Mocket.r_fd and Mocket.w_fd:
-            os.write(Mocket.w_fd, content)
-
-
 def hexdump(binary_string):
     r"""
     >>> hexdump(b"bar foobar foo") == decode_from_bytes(encode_to_bytes("62 61 72 20 66 6F 6F 62 61 72 20 66 6F 6F"))