Added set_p and set_r methods

Along with full support for them in set_tmpcfg, and a bunch of test
cases.

pdbuddy/__init__.py

         if len(out):
             raise ValueError(out[0])
 
+    def set_p(self, mw):
+        """Sets the power of the configuration buffer, in milliwatts"""
+        out = self.send_command("set_p {}".format(mw))
+        # If that command gave any output, that indicates an error.  Raise an
+        # exception to make that clear.
+        if len(out):
+            raise ValueError(out[0])
+
+    def set_r(self, mr):
+        """Sets the resistance of the configuration buffer, in milliohms"""
+        out = self.send_command("set_r {}".format(mr))
+        # If that command gave any output, that indicates an error.  Raise an
+        # exception to make that clear.
+        if len(out):
+            raise ValueError(out[0])
+
     def identify(self):
         """Blinks the LED quickly"""
         self.send_command("identify")
         # Set voltage range
         self.set_vrange(sc.vmin, sc.vmax)
         
-        # Set current
-        self.set_i(sc.i)
+        if sc.idim is SinkDimension.CURRENT:
+            # Set current
+            self.set_i(sc.i)
+        elif sc.idim is SinkDimension.POWER:
+            # Set power
+            self.set_p(sc.i)
+        elif sc.idim is SinkDimension.RESISTANCE:
+            # Set resistance
+            self.set_r(sc.i)
 
     @classmethod
     def get_devices(cls):

test_pdbuddy/__init__.py

         self.obj_range = pdbuddy.SinkConfig(status=pdbuddy.SinkStatus.VALID,
                 flags=pdbuddy.SinkFlags.HV_PREFERRED, v=13800, vmin=12000,
                 vmax=16000, i=2000, idim=pdbuddy.SinkDimension.CURRENT)
+        self.obj_valid_p = pdbuddy.SinkConfig(status=pdbuddy.SinkStatus.VALID,
+                flags=pdbuddy.SinkFlags.NONE, v=15000, vmin=None, vmax=None,
+                i=35000, idim=pdbuddy.SinkDimension.POWER)
+        self.obj_valid_r = pdbuddy.SinkConfig(status=pdbuddy.SinkStatus.VALID,
+                flags=pdbuddy.SinkFlags.NONE, v=15000, vmin=None, vmax=None,
+                i=10000, idim=pdbuddy.SinkDimension.RESISTANCE)
 
         self.obj_huge_v = pdbuddy.SinkConfig(status=pdbuddy.SinkStatus.VALID,
                 flags=pdbuddy.SinkFlags.NONE, v=65536, vmin=None, vmax=None,
                 flags=pdbuddy.SinkFlags.NONE, v=5000, vmin=None, vmax=None,
                 i=-1, idim=pdbuddy.SinkDimension.CURRENT)
 
+        self.obj_neg_p = pdbuddy.SinkConfig(status=pdbuddy.SinkStatus.VALID,
+                flags=pdbuddy.SinkFlags.NONE, v=15000, vmin=None, vmax=None,
+                i=-1, idim=pdbuddy.SinkDimension.POWER)
+        self.obj_neg_r = pdbuddy.SinkConfig(status=pdbuddy.SinkStatus.VALID,
+                flags=pdbuddy.SinkFlags.NONE, v=15000, vmin=None, vmax=None,
+                i=-1, idim=pdbuddy.SinkDimension.RESISTANCE)
+
     def tearDown(self):
         # Close the connection to the PD Buddy Sink
         self.pdbs.close()
         self.pdbs.set_tmpcfg(self.obj_range)
         self.assertEqual(self.pdbs.get_tmpcfg(), self.obj_range)
 
+    def test_set_tmpcfg_valid_p(self):
+        self.pdbs.set_tmpcfg(self.obj_valid_p)
+        self.assertEqual(self.pdbs.get_tmpcfg(), self.obj_valid_p)
+
+    def test_set_tmpcfg_valid_r(self):
+        self.pdbs.set_tmpcfg(self.obj_valid_r)
+        self.assertEqual(self.pdbs.get_tmpcfg(), self.obj_valid_r)
+
     def test_set_tmpcfg_huge_v(self):
         with self.assertRaises(ValueError):
             self.pdbs.set_tmpcfg(self.obj_huge_v)
         with self.assertRaises(ValueError):
             self.pdbs.set_tmpcfg(self.obj_neg_i)
 
+    def test_set_tmpcfg_neg_p(self):
+        with self.assertRaises(ValueError):
+            self.pdbs.set_tmpcfg(self.obj_neg_p)
+
+    def test_set_tmpcfg_neg_r(self):
+        with self.assertRaises(ValueError):
+            self.pdbs.set_tmpcfg(self.obj_neg_r)
+
     def test_write(self):
         self.test_set_tmpcfg_valid()
         self.pdbs.write()