1 files changed, 51 insertions, 1 deletions
diff --git a/Lib/tkinter/test/test_tkinter/test_variables.py b/Lib/tkinter/test/test_tkinter/test_variables.py
index d8ba9cea74..2eb1e12671 100644
--- a/Lib/tkinter/test/test_tkinter/test_variables.py
+++ b/Lib/tkinter/test/test_tkinter/test_variables.py
@@ -87,7 +87,8 @@ class TestVariable(TestBase):
         v.set("value")
         self.assertTrue(v.side_effect)
 
-    def test_trace(self):
+    def test_trace_old(self):
+        # Old interface
         v = Variable(self.root)
         vname = str(v)
         trace = []
@@ -136,6 +137,55 @@ class TestVariable(TestBase):
         gc.collect()
         self.assertEqual(trace, [('write', vname, '', 'u')])
 
+    def test_trace(self):
+        v = Variable(self.root)
+        vname = str(v)
+        trace = []
+        def read_tracer(*args):
+            trace.append(('read',) + args)
+        def write_tracer(*args):
+            trace.append(('write',) + args)
+        tr1 = v.trace_add('read', read_tracer)
+        tr2 = v.trace_add(['write', 'unset'], write_tracer)
+        self.assertEqual(sorted(v.trace_info()), [
+                         (('read',), tr1),
+                         (('write', 'unset'), tr2)])
+        self.assertEqual(trace, [])
+
+        v.set('spam')
+        self.assertEqual(trace, [('write', vname, '', 'write')])
+
+        trace = []
+        v.get()
+        self.assertEqual(trace, [('read', vname, '', 'read')])
+
+        trace = []
+        info = sorted(v.trace_info())
+        v.trace_remove('write', tr1)  # Wrong mode
+        self.assertEqual(sorted(v.trace_info()), info)
+        with self.assertRaises(TclError):
+            v.trace_remove('read', 'spam')  # Wrong command name
+        self.assertEqual(sorted(v.trace_info()), info)
+        v.get()
+        self.assertEqual(trace, [('read', vname, '', 'read')])
+
+        trace = []
+        v.trace_remove('read', tr1)
+        self.assertEqual(v.trace_info(), [(('write', 'unset'), tr2)])
+        v.get()
+        self.assertEqual(trace, [])
+
+        trace = []
+        del write_tracer
+        gc.collect()
+        v.set('eggs')
+        self.assertEqual(trace, [('write', vname, '', 'write')])
+
+        trace = []
+        del v
+        gc.collect()
+        self.assertEqual(trace, [('write', vname, '', 'unset')])
+
 
 class TestStringVar(TestBase):