test-runner: remove special case for "root" namespace

This was a placeholder at one point but modules grew to depend on it
being a string. Fix these dependencies and set the root namespace
name to None so there is no more special case needed to handle both
a named namespace and the original 'root' namespace.

autotests/util/hwsim.py

@@ -301,15 +301,15 @@ class Hwsim(iwd.AsyncOpAbstract):
     _instances = WeakValueDictionary()
 
     def __new__(cls, namespace=ctx):
-        name = namespace.name
+        key = id(namespace)
 
-        if name not in cls._instances.keys():
+        if key not in cls._instances.keys():
             obj = object.__new__(cls)
             obj._initialized = False
 
-            cls._instances[name] = obj
+            cls._instances[key] = obj
 
-        return cls._instances[name]
+        return cls._instances[key]
 
     def __init__(self, namespace=ctx):
         if self._initialized:

autotests/util/iwd.py

@@ -1053,7 +1053,7 @@ class IWD(AsyncOpAbstract):
         # reference so that __del__ gets called when it's released. This is only
         # done for the root namespace in order to allow testutil to function
         # correctly in non-namespace tests.
-        if self.namespace.name == "root":
+        if self.namespace.name is None:
             IWD._default_instance = weakref.ref(self)
 
     def __del__(self):

tools/test-runner

@@ -599,12 +599,6 @@ class Namespace:
 		return self._bus
 
 	def start_process(self, args, env=None, **kwargs):
-		# Special case for 'root' namespace (aka TestContext)
-		if self.name == "root":
-			ns = None
-		else:
-			ns = self.name
-
 		if not env:
 			env = os.environ.copy()
 
@@ -612,7 +606,7 @@ class Namespace:
 			# In case this process needs DBus...
 			env['DBUS_SYSTEM_BUS_ADDRESS'] = self.dbus_address
 
-		p = Process(args, namespace=ns, env=env, **kwargs)
+		p = Process(args, namespace=self.name, env=env, **kwargs)
 
 		if not kwargs.get('wait', False):
 			self.processes.append(p)
@@ -791,7 +785,7 @@ class TestContext(Namespace):
 		such as processes, radios, interfaces and test results.
 	'''
 	def __init__(self, args):
-		self.name = "root"
+		self.name = None
 		self.processes = []
 		self.args = args
 		self.hw_config = None