Add tests for callback infrastructure

IPython/core/tests/test_callbacks.py

@@ -0,0 +1,46 b''
+import unittest
+try:  # Python 3.3 +
+    from unittest.mock import Mock
+except ImportError:
+    from mock import Mock
+
+from IPython.core import callbacks
+import IPython.testing.tools as tt
+
+def ping_received():
+    pass
+
+class CallbackTests(unittest.TestCase):
+    def setUp(self):
+        self.cbm = callbacks.CallbackManager(get_ipython(), {'ping_received': ping_received})
+    
+    def test_register_unregister(self):
+        cb = Mock()
+
+        self.cbm.register('ping_received', cb)        
+        self.cbm.fire('ping_received')
+        self.assertEqual(cb.call_count, 1)
+        
+        self.cbm.unregister('ping_received', cb)
+        self.cbm.fire('ping_received')
+        self.assertEqual(cb.call_count, 1)
+    
+    def test_reset(self):
+        cb = Mock()
+        self.cbm.register('ping_received', cb)
+        self.cbm.reset('ping_received')
+        self.cbm.fire('ping_received')
+        assert not cb.called
+    
+    def test_reset_all(self):
+        cb = Mock()
+        self.cbm.register('ping_received', cb)
+        self.cbm.reset_all()
+        self.cbm.fire('ping_received')
+        assert not cb.called
+    
+    def test_cb_error(self):
+        cb = Mock(side_effect=ValueError)
+        self.cbm.register('ping_received', cb)
+        with tt.AssertPrints("Error in callback"):
+            self.cbm.fire('ping_received')
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