diff --git a/tests/test_network.py b/tests/test_network.py
index f16b984..457ffda 100644
--- a/tests/test_network.py
+++ b/tests/test_network.py
@@ -32,6 +32,7 @@ from pytest_mock import MockerFixture
 
 from secret_handshake import SHSClient, SHSServer
 from secret_handshake.boxstream import BoxStreamKeys
+from secret_handshake.network import SHSDuplexStream
 
 from .helpers import AsyncBuffer
 
@@ -169,3 +170,30 @@ async def test_server(mocker: MockerFixture) -> None:
 
     await server.listen()
     await wait_for(resolve.wait(), 5)
+
+
+def test_duplex_write(mocker: MockerFixture) -> None:
+    """Test the writing capabilities of the duplex stream"""
+
+    d_stream = SHSDuplexStream()
+    d_stream.write_stream = mocker.AsyncMock()
+    d_stream.write(b"thing")
+
+    d_stream.write_stream.write.assert_called_once_with(b"thing")
+
+
+def test_duplex_close_no_write_stream() -> None:
+    """Test if SHSDuplexStream’s close method doesn’t fail if there is no write stream"""
+
+    d_stream = SHSDuplexStream()
+    assert d_stream.write_stream is None
+    d_stream.close()
+
+    # We cannot really do assertions here. If there is not set (it is None), the above call would fail
+
+
+def test_duplex_stream_aiter() -> None:
+    """Test if the __aiter__ method of SHSDuplexStream returns the stream itself"""
+
+    d_stream = SHSDuplexStream()
+    assert d_stream.__aiter__() is d_stream  # pylint: disable=unnecessary-dunder-call