DOM for flat memory transceiver modules (sonic-net#3950)

* Fix: show interface transceiver info Ethernet0 command fails for CMIS SFP

* Fix variable name error.

* Return DOM for flat memory modules if it's available.

* Update unit tests.

* Update unit tests.

* Update unit tests.

* Update unit tests.

Author: az-pz

sfputil/main.py

@@ -695,10 +695,6 @@ def eeprom(port, dump_dom, namespace):
                         output += "API is none while getting DOM info!\n"
                         click.echo(output)
                         sys.exit(ERROR_NOT_IMPLEMENTED)
-                    else:
-                        if api.is_flat_memory():
-                            output += "DOM values not supported for flat memory module\n"
-                            continue
                     try:
                         xcvr_dom_info = platform_chassis.get_sfp(physical_port).get_transceiver_dom_real_value()
                     except NotImplementedError:

tests/sfputil_test.py

@@ -60,6 +60,13 @@
         Vendor Rev: A2
         Vendor SN: MT1636VS10561
 """
+EMPTY_DOM_VALUES = """        ChannelMonitorValues:
+        ChannelThresholdValues:
+        ModuleMonitorValues:
+        ModuleThresholdValues:
+
+
+"""
 
 class TestSfputil(object):
     def test_format_dict_value_to_string(self):
@@ -676,7 +683,7 @@ def test_show_eeprom_RJ45(self, mock_chassis):
     @patch('sfputil.main.platform_sfputil', MagicMock(is_logical_port=MagicMock(return_value=1)))
     @patch('sfputil.main.is_port_type_rj45', MagicMock(return_value=False))
     @pytest.mark.parametrize("exception, xcvr_api_none, expected_output", [
-        (None, False, '''DOM values not supported for flat memory module\n\n'''),
+        (None, False, EMPTY_DOM_VALUES),
         (NotImplementedError, False, '''API is currently not implemented for this platform\n\n'''),
         (None, True, '''API is none while getting DOM info!\n\n''')
     ])