Multichannel instrument consistency for optical spectrum analyzer

src/instruments/abstract_instruments/optical_spectrum_analyzer.py

@@ -5,10 +5,10 @@
 
 # IMPORTS #####################################################################
 
-
 import abc
 
 from instruments.abstract_instruments import Instrument
+from instruments.util_fns import ProxyList
 
 # CLASSES #####################################################################
 
@@ -21,14 +21,29 @@ class OpticalSpectrumAnalyzer(Instrument, metaclass=abc.ABCMeta):
     provide a consistent interface to the user.
     """
 
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self._channel_count = 1
+
     class Channel(metaclass=abc.ABCMeta):
         """
         Abstract base class for physical channels on an optical spectrum analyzer.
 
         All applicable concrete instruments should inherit from this ABC to
         provide a consistent interface to the user.
+
+        Optical spectrum analyzers that only have a single channel do not need to
+        define their own concrete implementation of this class. Ones with
+        multiple channels need their own definition of this class, where
+        this class contains the concrete implementations of the below
+        abstract methods. Instruments with 1 channel have their concrete
+        implementations at the parent instrument level.
         """
 
+        def __init__(self, parent, name):
+            self._parent = parent
+            self._name = name
+
         # METHODS #
 
         @abc.abstractmethod
@@ -42,7 +57,10 @@ def wavelength(self, bin_format=True):
             :return: The wavelength component of the waveform.
             :rtype: `numpy.ndarray`
             """
-            raise NotImplementedError
+            if self._parent._channel_count == 1:
+                return self._parent.wavelength(bin_format=bin_format)
+            else:
+                raise NotImplementedError
 
         @abc.abstractmethod
         def data(self, bin_format=True):
@@ -55,22 +73,23 @@ def data(self, bin_format=True):
             :return: The y-component of the waveform.
             :rtype: `numpy.ndarray`
             """
-            raise NotImplementedError
+            if self._parent._channel_count == 1:
+                return self._parent.data(bin_format=bin_format)
+            else:
+                raise NotImplementedError
 
     # PROPERTIES #
 
     @property
-    @abc.abstractmethod
     def channel(self):
         """
         Gets an iterator or list for easy Pythonic access to the various
         channel objects on the OSA instrument. Typically generated
         by the `~instruments.util_fns.ProxyList` helper.
         """
-        raise NotImplementedError
+        return ProxyList(self, self.Channel, range(self._channel_count))
 
     @property
-    @abc.abstractmethod
     def start_wl(self):
         """
         Gets/sets the the start wavelength of the OSA. This is
@@ -81,12 +100,10 @@ def start_wl(self):
         raise NotImplementedError
 
     @start_wl.setter
-    @abc.abstractmethod
     def start_wl(self, newval):
         raise NotImplementedError
 
     @property
-    @abc.abstractmethod
     def stop_wl(self):
         """
         Gets/sets the the stop wavelength of the OSA. This is
@@ -97,12 +114,10 @@ def stop_wl(self):
         raise NotImplementedError
 
     @stop_wl.setter
-    @abc.abstractmethod
     def stop_wl(self, newval):
         raise NotImplementedError
 
     @property
-    @abc.abstractmethod
     def bandwidth(self):
         """
         Gets/sets the the bandwidth of the OSA. This is
@@ -113,7 +128,6 @@ def bandwidth(self):
         raise NotImplementedError
 
     @bandwidth.setter
-    @abc.abstractmethod
     def bandwidth(self, newval):
         raise NotImplementedError
 
@@ -125,3 +139,33 @@ def start_sweep(self):
         Forces a start sweep on the attached OSA.
         """
         raise NotImplementedError
+
+    def wavelength(self, bin_format=True):
+        """
+        Gets the x-axis of the specified data source channel. This is an
+        abstract property.
+
+        :param bool bin_format: If the waveform should be transfered in binary
+            (``True``) or ASCII (``False``) formats.
+        :return: The wavelength component of the waveform.
+        :rtype: `numpy.ndarray`
+        """
+        if self._channel_count > 1:
+            return self.channel[0].wavelength(bin_format=bin_format)
+        else:
+            raise NotImplementedError
+
+    def data(self, bin_format=True):
+        """
+        Gets the y-axis of the specified data source channel. This is an
+        abstract property.
+
+        :param bool bin_format: If the waveform should be transfered in binary
+            (``True``) or ASCII (``False``) formats.
+        :return: The y-component of the waveform.
+        :rtype: `numpy.ndarray`
+        """
+        if self._channel_count > 1:
+            return self.channel[0].data(bin_format=bin_format)
+        else:
+            raise NotImplementedError

src/instruments/yokogawa/yokogawa6370.py

@@ -7,7 +7,6 @@
 
 
 from enum import IntEnum, Enum
-import hashlib
 
 from instruments.units import ureg as u
 
@@ -46,6 +45,7 @@ class Yokogawa6370(OpticalSpectrumAnalyzer):
 
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
+        self._channel_count = len(self.Traces)
 
         if isinstance(self._file, SocketCommunicator):
             self.terminator = "\r\n"  # TCP IP connection terminator

tests/test_abstract_inst/test_optical_spectrum_analyzer.py

@@ -19,15 +19,9 @@
 def osa(monkeypatch):
     """Patch and return Optical Spectrum Analyzer class for access."""
     inst = ik.abstract_instruments.OpticalSpectrumAnalyzer
+    chan = ik.abstract_instruments.OpticalSpectrumAnalyzer.Channel
     monkeypatch.setattr(inst, "__abstractmethods__", set())
-    return inst
-
-
-@pytest.fixture
-def osc(monkeypatch):
-    """Patch and return OSAChannel class for access."""
-    inst = ik.abstract_instruments.OpticalSpectrumAnalyzer.Channel
-    monkeypatch.setattr(inst, "__abstractmethods__", set())
+    monkeypatch.setattr(chan, "__abstractmethods__", set())
     return inst
 
 
@@ -37,8 +31,8 @@ def osc(monkeypatch):
 def test_osa_channel(osa):
     """Get channel: ensure existence."""
     with expected_protocol(osa, [], []) as inst:
-        with pytest.raises(NotImplementedError):
-            _ = inst.channel
+        ch = inst.channel[0]
+        assert isinstance(ch, ik.abstract_instruments.OpticalSpectrumAnalyzer.Channel)
 
 
 def test_osa_start_wl(osa):
@@ -78,15 +72,25 @@ def test_osa_start_sweep(osa):
 # OSAChannel #
 
 
-def test_osa_channel_wavelength(osc):
+@pytest.mark.parametrize("num_ch", [1, 5])
+def test_osa_channel_wavelength(osa, num_ch):
     """Channel wavelength method: ensure existence."""
-    inst = osc()
-    with pytest.raises(NotImplementedError):
-        inst.wavelength()
+    with expected_protocol(osa, [], []) as inst:
+        inst._channel_count = num_ch
+        ch = inst.channel[0]
+        with pytest.raises(NotImplementedError):
+            ch.wavelength()
+        with pytest.raises(NotImplementedError):
+            inst.wavelength()  # single channel instrument
 
 
-def test_osa_channel_data(osc):
+@pytest.mark.parametrize("num_ch", [1, 5])
+def test_osa_channel_data(osa, num_ch):
     """Channel data method: ensure existence."""
-    inst = osc()
-    with pytest.raises(NotImplementedError):
-        inst.data()
+    with expected_protocol(osa, [], []) as inst:
+        inst._channel_count = num_ch
+        ch = inst.channel[0]
+        with pytest.raises(NotImplementedError):
+            ch.data()
+        with pytest.raises(NotImplementedError):
+            inst.data()  # single channel instrument

tests/test_yokogawa/test_yokogawa_6370.py

@@ -5,7 +5,6 @@
 
 # IMPORTS #####################################################################
 
-import hashlib
 import struct
 
 from hypothesis import (
@@ -15,7 +14,6 @@
 import socket
 
 import instruments as ik
-from instruments.abstract_instruments.comm import SocketCommunicator
 from instruments.optional_dep_finder import numpy
 from tests import (
     expected_protocol,
@@ -31,6 +29,7 @@
 
 def test_channel_is_channel_class():
     inst = ik.yokogawa.Yokogawa6370.open_test()
+    assert inst._channel_count == len(inst.Traces)
     assert isinstance(inst.channel["A"], inst.Channel) is True