Add warning/critical thresholds for PSU power (sonic-net#304)

Add warning/critical thresholds for PSU power

Signed-off-by: Stephen Sun <[email protected]>

sonic_platform_base/psu_base.py

@@ -223,6 +223,26 @@ def get_maximum_supplied_power(self):
         """
         raise NotImplementedError
 
+    def get_psu_power_warning_suppress_threshold(self):
+        """
+        Retrieve the warning suppress threshold of the power on this PSU
+        The value can be volatile, so the caller should call the API each time it is used.
+
+        Returns:
+            A float number, the warning suppress threshold of the PSU in watts.
+        """
+        raise NotImplementedError
+
+    def get_psu_power_critical_threshold(self):
+        """
+        Retrieve the critical threshold of the power on this PSU
+        The value can be volatile, so the caller should call the API each time it is used.
+
+        Returns:
+            A float number, the critical threshold of the PSU in watts.
+        """
+        raise NotImplementedError
+
     @classmethod
     def get_status_master_led(cls):
         """

tests/psu_base_test.py

@@ -0,0 +1,29 @@
+from sonic_platform_base.psu_base import PsuBase
+
+class TestPsuBase:
+
+    def test_psu_base(self):
+        psu = PsuBase()
+        not_implemented_methods = [
+            psu.get_voltage,
+            psu.get_current,
+            psu.get_power,
+            psu.get_powergood_status,
+            psu.get_temperature,
+            psu.get_temperature_high_threshold,
+            psu.get_voltage_high_threshold,
+            psu.get_voltage_low_threshold,
+            psu.get_maximum_supplied_power,
+            psu.get_psu_power_warning_suppress_threshold,
+            psu.get_psu_power_critical_threshold,
+            psu.get_input_voltage,
+            psu.get_input_current]
+
+        for method in not_implemented_methods:
+            exception_raised = False
+            try:
+                method()
+            except NotImplementedError:
+                exception_raised = True
+
+            assert exception_raised