From 5fa019d46b755078aea791cd569b64ef7cc92edc Mon Sep 17 00:00:00 2001
From: Gary Yendell <gary.yendell@diamond.ac.uk>
Date: Tue, 16 Apr 2024 11:42:26 +0100
Subject: [PATCH] Add epics_signal_rw_rbv helper function

Add tests for all signal creation helpers
---
 src/ophyd_async/epics/signal/signal.py | 19 ++++++++++++++
 tests/core/test_signal.py              | 34 ++++++++++++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/src/ophyd_async/epics/signal/signal.py b/src/ophyd_async/epics/signal/signal.py
index d4259c66c8..3aa071ad0d 100644
--- a/src/ophyd_async/epics/signal/signal.py
+++ b/src/ophyd_async/epics/signal/signal.py
@@ -58,6 +58,25 @@ def epics_signal_rw(
     return SignalRW(backend)
 
 
+def epics_signal_rw_rbv(
+    datatype: Type[T],
+    write_pv: Optional[str] = None,
+    read_suffix: str = "_RBV",
+) -> SignalRW[T]:
+    """Create a `SignalRW` backed by 1 or 2 EPICS PVs, with a suffix on the readback pv
+
+    Parameters
+    ----------
+    datatype:
+        Check that the PV is of this type
+    write_pv:
+        The PV to write to
+    read_suffix:
+        Append this suffix to the write pv to create the readback pv
+    """
+    return epics_signal_rw(datatype, f"{write_pv}{read_suffix}", write_pv)
+
+
 def epics_signal_r(datatype: Type[T], read_pv: str) -> SignalR[T]:
     """Create a `SignalR` backed by 1 EPICS PV
 
diff --git a/tests/core/test_signal.py b/tests/core/test_signal.py
index 5393cb1a78..e7460ac4a9 100644
--- a/tests/core/test_signal.py
+++ b/tests/core/test_signal.py
@@ -14,6 +14,13 @@
     wait_for_value,
 )
 from ophyd_async.core.utils import DEFAULT_TIMEOUT
+from ophyd_async.epics.signal.signal import (
+    epics_signal_r,
+    epics_signal_rw,
+    epics_signal_rw_rbv,
+    epics_signal_w,
+    epics_signal_x,
+)
 
 
 class MySignal(Signal):
@@ -119,3 +126,30 @@ async def test_set_and_wait_for_value():
     assert not st.done
     set_sim_put_proceeds(sim_signal, True)
     assert await time_taken_by(st) < 0.1
+
+
+def test_signal_helpers():
+    read_write = epics_signal_rw(int, "ReadWrite")
+    assert read_write._backend.read_pv == "ReadWrite"
+    assert read_write._backend.write_pv == "ReadWrite"
+
+    read_write_rbv_manual = epics_signal_rw(int, "ReadWrite_RBV", "ReadWrite")
+    assert read_write_rbv_manual._backend.read_pv == "ReadWrite_RBV"
+    assert read_write_rbv_manual._backend.write_pv == "ReadWrite"
+
+    read_write_rbv = epics_signal_rw_rbv(int, "ReadWrite")
+    assert read_write_rbv._backend.read_pv == "ReadWrite_RBV"
+    assert read_write_rbv._backend.write_pv == "ReadWrite"
+
+    read_write_rbv_suffix = epics_signal_rw_rbv(int, "ReadWrite", read_suffix=":RBV")
+    assert read_write_rbv_suffix._backend.read_pv == "ReadWrite:RBV"
+    assert read_write_rbv_suffix._backend.write_pv == "ReadWrite"
+
+    read = epics_signal_r(int, "Read")
+    assert read._backend.read_pv == "Read"
+
+    write = epics_signal_w(int, "Write")
+    assert write._backend.write_pv == "Write"
+
+    execute = epics_signal_x("Execute")
+    assert execute._backend.write_pv == "Execute"