diff --git a/rest_framework/routers.py b/rest_framework/routers.py
index 850bb408e..7bbfc12ec 100644
--- a/rest_framework/routers.py
+++ b/rest_framework/routers.py
@@ -68,16 +68,18 @@ class RouteTree:
         been set or if the path doesn't exist.
         """
         routes = self.routes
+        parent_path = []
 
         for part in path:
             if part not in routes:
-                # TODO: invalid path error message
-                raise KeyError('')
-            routes = routes[path].routes
+                on_path = (' on path %s' % parent_path) if len(parent_path) > 0 else ''
+                raise KeyError('Parent route "%s"%s was not registred' % (part, on_path))
+            parent_path.append(part)
+            routes = routes[part].routes
 
         if name in routes:
-            # TODO: route name already exists error message
-            raise KeyError('')
+            on_path = (' on path %s' % path) if len(path) > 0 else ''
+            raise KeyError('Route "%s" already set%s' % (name, on_path))
 
         routes[name] = self.Node({}, value)
 
diff --git a/tests/test_routers.py b/tests/test_routers.py
index f45039f80..351a0f61e 100644
--- a/tests/test_routers.py
+++ b/tests/test_routers.py
@@ -10,7 +10,7 @@ from django.test import TestCase, override_settings
 from rest_framework import permissions, serializers, viewsets
 from rest_framework.decorators import detail_route, list_route
 from rest_framework.response import Response
-from rest_framework.routers import DefaultRouter, SimpleRouter
+from rest_framework.routers import DefaultRouter, RouteTree, SimpleRouter
 from rest_framework.test import APIRequestFactory
 
 factory = APIRequestFactory()
@@ -89,6 +89,53 @@ class BasicViewSet(viewsets.ViewSet):
         return Response({'method': 'link2'})
 
 
+class TestRouteTree(TestCase):
+    def setUp(self):
+        self.tree = RouteTree()
+
+    def test_set(self):
+        """
+        Should set the value for the given name and path.
+        """
+        self.tree.set(1, [], 'A')
+        self.tree.set(2, ['A'], 'B')
+        self.tree.set(3, ['A', 'B'], 'C')
+
+        root = self.tree.routes
+        self.assertEqual(list(root.keys()), ['A'])
+        self.assertEqual(root['A'].value, 1)
+        self.assertEqual(list(root['A'].routes.keys()), ['B'])
+        self.assertEqual(root['A'].routes['B'].value, 2)
+        self.assertEqual(list(root['A'].routes['B'].routes.keys()), ['C'])
+        self.assertEqual(root['A'].routes['B'].routes['C'].value, 3)
+
+    def test_set_invalid(self):
+        """
+        A KeyError should be raised for an invalid name or path.
+        """
+        self.tree.set(1, [], 'A')
+        self.tree.set(2, ['A'], 'B')
+
+        with self.assertRaises(KeyError):
+            self.tree.set(5, ['A', 'B', 'C', 'C'], 'E')
+
+        with self.assertRaises(KeyError):
+            self.tree.set(20, ['A'], 'B')
+
+    def test_get(self):
+        """
+        Should return a list of (name, value) for each node on
+        the path.
+        """
+        self.tree.set(1, [], 'A')
+        self.tree.set(2, ['A'], 'B')
+        self.tree.set(3, ['A', 'B'], 'C')
+
+        self.assertEqual(self.tree.get(['A', 'B'], 'C'), [
+            ('A', 1), ('B', 2), ('C', 3)
+        ])
+
+
 class TestSimpleRouter(TestCase):
     def setUp(self):
         self.router = SimpleRouter()