diff --git a/tests/test_components.py b/tests/test_components.py
index e37e10b9..e5b6138e 100644
--- a/tests/test_components.py
+++ b/tests/test_components.py
@@ -17,6 +17,7 @@
 
 import signal
 import unittest
+import unittest.mock
 from contextlib import contextmanager
 
 import numpy as np
@@ -197,6 +198,41 @@ def test_samecomponent(self):
         self.assertFalse(g.samecomponent(g[1], g[2]))
 
 
+class TestNotRecomputed(unittest.TestCase):
+    """The traversal runs once, and again only after the graph has changed"""
+
+    def traversals(self, g, ask):
+        calls = []
+        original = type(g[0]).adjacent
+
+        def spy(vertex, *args, **kwargs):
+            calls.append(vertex)
+            return original(vertex, *args, **kwargs)
+
+        with unittest.mock.patch.object(type(g[0]), "adjacent", spy):
+            ask()
+        return len(calls)
+
+    def check(self, cls):
+        g = build(cls, 4, [(0, 1), (2, 3)])
+        ask = lambda: (g.nc, g.component(g[0]), g.samecomponent(g[0], g[1]), g[2].label)
+
+        self.assertGreater(self.traversals(g, ask), 0)  # first time: does the work
+        self.assertEqual(self.traversals(g, ask), 0)  # nothing changed: none
+        self.assertEqual(self.traversals(g, ask), 0)
+
+        g.add_edge(g[1], g[2])  # a change: once more, and the answer is new
+        self.assertGreater(self.traversals(g, ask), 0)
+        self.assertEqual(g.nc, 1)
+        self.assertEqual(self.traversals(g, ask), 0)
+
+    def test_undirected(self):
+        self.check(UGraph)
+
+    def test_directed(self):
+        self.check(DGraph)
+
+
 class TestUndirectedComponents(_Components, unittest.TestCase):
     cls = UGraph
 
diff --git a/tests/test_export.py b/tests/test_export.py
index 52df2ec2..8afec4c5 100644
--- a/tests/test_export.py
+++ b/tests/test_export.py
@@ -408,6 +408,8 @@ def test_dotfile_prints_to_console(self):
             g.dotfile()
         self.assertEqual(out.getvalue(), g.export(format="dot", costs=False))
         self.assertNotIn("label=", out.getvalue())
+        # writing to the console must leave it usable (0.6.5 closed it)
+        self.assertFalse(out.closed)
 
     def test_dotfile_to_path_and_stream(self):
         g, *_ = line_graph(UGraph)
diff --git a/tests/test_graph.py b/tests/test_graph.py
index f8d6204d..c0249c25 100644
--- a/tests/test_graph.py
+++ b/tests/test_graph.py
@@ -298,6 +298,24 @@ def test_edge_vertices_deprecated(self):
             verts = e.vertices()
         self.assertEqual(verts, e.endpoints)
 
+    def test_planners_validate_start_and_goal(self):
+        # 0.6.5 checked the type of the start twice and never the goal
+        g = UGraph()
+        a = g.add_vertex(coord=[0, 0], name="a")
+        b = g.add_vertex(coord=[1, 0], name="b")
+        g.add_edge(a, b)
+
+        for planner in (g.path_BFS, g.path_UCS, g.path_Astar):
+            with self.subTest(planner=planner.__name__):
+                with self.assertRaises(TypeError):
+                    planner(a, 42)
+                with self.assertRaises(TypeError):
+                    planner(42, b)
+                with self.assertRaises(KeyError):
+                    planner(a, "no such vertex")
+                # by name and by reference both work
+                self.assertEqual(planner("a", "b")[0], [a, b])
+
     def test_edge3(self):
 
         g = UGraph()