diff --git a/tests/test__frame_helper.py b/tests/test__frame_helper.py
index 1bf60ed..092e1b8 100644
--- a/tests/test__frame_helper.py
+++ b/tests/test__frame_helper.py
@@ -41,6 +41,16 @@ from .conftest import get_mock_connection_params
 PREAMBLE = b"\x00"
 
 
+def _make_noise_hello_pkt(hello_pkt: bytes) -> bytes:
+    """Make a noise hello packet."""
+    preamble = 1
+    hello_pkg_length = len(hello_pkt)
+    hello_pkg_length_high = (hello_pkg_length >> 8) & 0xFF
+    hello_pkg_length_low = hello_pkg_length & 0xFF
+    hello_header = bytes((preamble, hello_pkg_length_high, hello_pkg_length_low))
+    return hello_header + hello_pkt
+
+
 def _mock_responder_proto(psk_bytes: bytes) -> NoiseConnection:
     proto = NoiseConnection.from_name(
         b"Noise_NNpsk0_25519_ChaChaPoly_SHA256", backend=ESPHOME_NOISE_BACKEND
@@ -446,13 +456,7 @@ async def test_noise_frame_helper_handshake_failure():
     decrypted = proto.read_message(encrypted_payload)
     assert decrypted == b""
 
-    hello_pkt = b"\x01servicetest\0"
-    preamble = 1
-    hello_pkg_length = len(hello_pkt)
-    hello_pkg_length_high = (hello_pkg_length >> 8) & 0xFF
-    hello_pkg_length_low = hello_pkg_length & 0xFF
-    hello_header = bytes((preamble, hello_pkg_length_high, hello_pkg_length_low))
-    hello_pkt_with_header = hello_header + hello_pkt
+    hello_pkt_with_header = _make_noise_hello_pkt(b"\x01servicetest\0")
     mock_data_received(helper, hello_pkt_with_header)
 
     error_pkt = b"\x01forced to fail"
@@ -513,13 +517,7 @@ async def test_noise_frame_helper_handshake_success_with_single_packet():
     decrypted = proto.read_message(encrypted_payload)
     assert decrypted == b""
 
-    hello_pkt = b"\x01servicetest\0"
-    preamble = 1
-    hello_pkg_length = len(hello_pkt)
-    hello_pkg_length_high = (hello_pkg_length >> 8) & 0xFF
-    hello_pkg_length_low = hello_pkg_length & 0xFF
-    hello_header = bytes((preamble, hello_pkg_length_high, hello_pkg_length_low))
-    hello_pkt_with_header = hello_header + hello_pkt
+    hello_pkt_with_header = _make_noise_hello_pkt(b"\x01servicetest\0")
     mock_data_received(helper, hello_pkt_with_header)
 
     handshake = proto.write_message(b"")
@@ -630,13 +628,7 @@ async def test_noise_frame_helper_empty_hello():
     )
 
     handshake_task = asyncio.create_task(helper.perform_handshake(30))
-    empty_hello_pkt = b""
-    preamble = 1
-    hello_pkg_length = len(empty_hello_pkt)
-    hello_pkg_length_high = (hello_pkg_length >> 8) & 0xFF
-    hello_pkg_length_low = hello_pkg_length & 0xFF
-    hello_header = bytes((preamble, hello_pkg_length_high, hello_pkg_length_low))
-    hello_pkt_with_header = hello_header + empty_hello_pkt
+    hello_pkt_with_header = _make_noise_hello_pkt(b"")
 
     mock_data_received(helper, hello_pkt_with_header)
 
@@ -644,6 +636,30 @@ async def test_noise_frame_helper_empty_hello():
         await handshake_task
 
 
+@pytest.mark.asyncio
+async def test_noise_frame_helper_wrong_protocol():
+    """Test noise with the wrong protocol."""
+    connection, _ = _make_mock_connection()
+    helper = MockAPINoiseFrameHelper(
+        connection=connection,
+        noise_psk="QRTIErOb/fcE9Ukd/5qA3RGYMn0Y+p06U58SCtOXvPc=",
+        expected_name="servicetest",
+        client_info="my client",
+        log_name="test",
+    )
+
+    handshake_task = asyncio.create_task(helper.perform_handshake(30))
+    # wrong protocol 5 instead of 1
+    hello_pkt_with_header = _make_noise_hello_pkt(b"\x05servicetest\0")
+
+    mock_data_received(helper, hello_pkt_with_header)
+
+    with pytest.raises(
+        HandshakeAPIError, match="Unknown protocol selected by client 5"
+    ):
+        await handshake_task
+
+
 @pytest.mark.asyncio
 async def test_init_noise_attempted_when_esp_uses_plaintext(
     noise_conn: APIConnection,