diff --git a/changelog.d/402.misc b/changelog.d/402.misc
new file mode 100644
index 00000000..73d2ff3f
--- /dev/null
+++ b/changelog.d/402.misc
@@ -0,0 +1 @@
+Fix unit tests by adding `setTcpNoDelay` to `FakeTransport`.
\ No newline at end of file
diff --git a/tests/twisted_test_helpers.py b/tests/twisted_test_helpers.py
index ea2b328c..f8fc3ab8 100644
--- a/tests/twisted_test_helpers.py
+++ b/tests/twisted_test_helpers.py
@@ -165,6 +165,9 @@ def flush(self, maxbytes=None):
             logger.info("FakeTransport: Buffer now empty, completing disconnect")
             self.disconnected = True
 
+    def setTcpNoDelay(self, new: bool) -> None:
+        pass
+
 
 def get_test_https_policy():
     """Get a test IPolicyForHTTPS which trusts the test CA cert