Generalize smartdevice child support (#775)

* Initialize children's modules (and features) using the child component negotiation results
* Set device_type based on the device response
* Print out child features in cli 'state'
* Add --child option to cli 'command' to allow targeting child devices
* Guard "generic" features like rssi, ssid, etc. only to devices which have this information

Note, we do not currently perform queries on child modules so some data may not be available. At the moment, a stop-gap solution to use parent's data is used but this is not always correct; even if the device shares the same clock and cloud connectivity, it may have its own firmware updates.

kasa/tests/test_smartdevice.py

@@ -37,6 +37,7 @@ from .conftest import (
     lightstrip,
     no_emeter_iot,
     plug,
+    strip,
     turn_on,
 )
 from .fakeprotocol_iot import FakeIotProtocol
@@ -201,13 +202,12 @@ async def test_representation(dev):
     assert pattern.match(str(dev))
 
 
-@device_iot
-async def test_childrens(dev):
-    """Make sure that children property is exposed by every device."""
-    if dev.is_strip:
-        assert len(dev.children) > 0
-    else:
-        assert len(dev.children) == 0
+@strip
+def test_children_api(dev):
+    """Test the child device API."""
+    first = dev.children[0]
+    first_by_get_child_device = dev.get_child_device(first.device_id)
+    assert first == first_by_get_child_device
 
 
 @device_iot
@@ -215,10 +215,8 @@ async def test_children(dev):
     """Make sure that children property is exposed by every device."""
     if dev.is_strip:
         assert len(dev.children) > 0
-        assert dev.has_children is True
     else:
         assert len(dev.children) == 0
-        assert dev.has_children is False
 
 
 @device_iot
@@ -260,7 +258,9 @@ async def test_device_class_ctors(device_class_name_obj):
     klass = device_class_name_obj[1]
     if issubclass(klass, SmartChildDevice):
         parent = SmartDevice(host, config=config)
-        dev = klass(parent, 1)
+        dev = klass(
+            parent, {"dummy": "info", "device_id": "dummy"}, {"dummy": "components"}
+        )
     else:
         dev = klass(host, config=config)
     assert dev.host == host