[Telemetry] Allow the Monsoon to power the device under test.

tools/telemetry/telemetry/core/platform/power_monitor/monsoon_power_monitor.py

Index: tools/telemetry/telemetry/core/platform/power_monitor/monsoon_power_monitor.py
diff --git a/tools/telemetry/telemetry/core/platform/power_monitor/monsoon_power_monitor.py b/tools/telemetry/telemetry/core/platform/power_monitor/monsoon_power_monitor.py
index 872f2176826fe7a2e1e6f2b87e9a56406a777c5a..00343e731252982a051d59b8048fb2fe4ec6249c 100644
--- a/tools/telemetry/telemetry/core/platform/power_monitor/monsoon_power_monitor.py
+++ b/tools/telemetry/telemetry/core/platform/power_monitor/monsoon_power_monitor.py
@@ -103,15 +103,16 @@ class MonsoonPowerMonitor(power_monitor.PowerMonitor):
     """
     power_samples = []
     total_energy_consumption_mwh = 0
+
     result = json.loads(powermonitor_output)
-    timedelta_h = result['duration_s'] / len(result['samples']) / 3600
-    for (current_a, voltage_v) in result['samples']:
-      energy_consumption_mw = current_a * voltage_v * 10**3
-      total_energy_consumption_mwh += energy_consumption_mw * timedelta_h
-      power_samples.append(energy_consumption_mw)
-    # -------- Collect and Process Data -------------
+    if result['samples']:
+      timedelta_h = result['duration_s'] / len(result['samples']) / 3600
+      for (current_a, voltage_v) in result['samples']:
+        energy_consumption_mw = current_a * voltage_v * 10**3
+        total_energy_consumption_mwh += energy_consumption_mw * timedelta_h
+        power_samples.append(energy_consumption_mw)
+
     out_dict = {}
-    # Raw power usage samples.
     out_dict['identifier'] = 'monsoon'
     out_dict['power_samples_mw'] = power_samples
     out_dict['energy_consumption_mwh'] = total_energy_consumption_mwh