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@@ -0,0 +1,7 b'' | |||
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1 | Update IPython event triggering to ensure callback registration and | |
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2 | unregistration only affects the set of callbacks the *next* time that event is | |
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3 | triggered. See :ghissue:`9447` and :ghpull:`9453`. | |
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4 | ||
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5 | This is a change to the existing semantics, wherein one callback registering a | |
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6 | second callback when triggered for an event would previously be invoked for | |
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7 | that same event. |
@@ -1,131 +1,131 b'' | |||
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1 | 1 | """Infrastructure for registering and firing callbacks on application events. |
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2 | 2 | |
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3 | 3 | Unlike :mod:`IPython.core.hooks`, which lets end users set single functions to |
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4 | 4 | be called at specific times, or a collection of alternative methods to try, |
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5 | 5 | callbacks are designed to be used by extension authors. A number of callbacks |
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6 | 6 | can be registered for the same event without needing to be aware of one another. |
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7 | 7 | |
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8 | 8 | The functions defined in this module are no-ops indicating the names of available |
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9 | 9 | events and the arguments which will be passed to them. |
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10 | 10 | |
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11 | 11 | .. note:: |
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12 | 12 | |
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13 | 13 | This API is experimental in IPython 2.0, and may be revised in future versions. |
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14 | 14 | """ |
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15 | 15 | from __future__ import print_function |
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16 | 16 | |
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17 | 17 | class EventManager(object): |
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18 | 18 | """Manage a collection of events and a sequence of callbacks for each. |
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19 | 19 | |
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20 | 20 | This is attached to :class:`~IPython.core.interactiveshell.InteractiveShell` |
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21 | 21 | instances as an ``events`` attribute. |
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22 | 22 | |
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23 | 23 | .. note:: |
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24 | 24 | |
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25 | 25 | This API is experimental in IPython 2.0, and may be revised in future versions. |
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26 | 26 | """ |
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27 | 27 | def __init__(self, shell, available_events): |
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28 | 28 | """Initialise the :class:`CallbackManager`. |
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29 | 29 | |
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30 | 30 | Parameters |
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31 | 31 | ---------- |
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32 | 32 | shell |
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33 | 33 | The :class:`~IPython.core.interactiveshell.InteractiveShell` instance |
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34 | 34 | available_callbacks |
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35 | 35 | An iterable of names for callback events. |
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36 | 36 | """ |
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37 | 37 | self.shell = shell |
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38 | 38 | self.callbacks = {n:[] for n in available_events} |
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39 | 39 | |
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40 | 40 | def register(self, event, function): |
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41 | 41 | """Register a new event callback |
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42 | 42 | |
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43 | 43 | Parameters |
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44 | 44 | ---------- |
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45 | 45 | event : str |
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46 | 46 | The event for which to register this callback. |
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47 | 47 | function : callable |
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48 | 48 | A function to be called on the given event. It should take the same |
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49 | 49 | parameters as the appropriate callback prototype. |
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50 | 50 | |
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51 | 51 | Raises |
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52 | 52 | ------ |
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53 | 53 | TypeError |
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54 | 54 | If ``function`` is not callable. |
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55 | 55 | KeyError |
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56 | 56 | If ``event`` is not one of the known events. |
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57 | 57 | """ |
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58 | 58 | if not callable(function): |
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59 | 59 | raise TypeError('Need a callable, got %r' % function) |
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60 | 60 | self.callbacks[event].append(function) |
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61 | 61 | |
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62 | 62 | def unregister(self, event, function): |
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63 | 63 | """Remove a callback from the given event.""" |
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64 | 64 | self.callbacks[event].remove(function) |
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65 | 65 | |
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66 | 66 | def trigger(self, event, *args, **kwargs): |
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67 | 67 | """Call callbacks for ``event``. |
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68 | 68 | |
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69 | 69 | Any additional arguments are passed to all callbacks registered for this |
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70 | 70 | event. Exceptions raised by callbacks are caught, and a message printed. |
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71 | 71 | """ |
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72 | for func in self.callbacks[event]: | |
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72 | for func in self.callbacks[event][:]: | |
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73 | 73 | try: |
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74 | 74 | func(*args, **kwargs) |
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75 | 75 | except Exception: |
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76 | 76 | print("Error in callback {} (for {}):".format(func, event)) |
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77 | 77 | self.shell.showtraceback() |
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78 | 78 | |
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79 | 79 | # event_name -> prototype mapping |
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80 | 80 | available_events = {} |
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81 | 81 | |
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82 | 82 | def _define_event(callback_proto): |
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83 | 83 | available_events[callback_proto.__name__] = callback_proto |
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84 | 84 | return callback_proto |
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85 | 85 | |
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86 | 86 | # ------------------------------------------------------------------------------ |
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87 | 87 | # Callback prototypes |
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88 | 88 | # |
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89 | 89 | # No-op functions which describe the names of available events and the |
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90 | 90 | # signatures of callbacks for those events. |
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91 | 91 | # ------------------------------------------------------------------------------ |
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92 | 92 | |
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93 | 93 | @_define_event |
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94 | 94 | def pre_execute(): |
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95 | 95 | """Fires before code is executed in response to user/frontend action. |
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96 | 96 | |
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97 | 97 | This includes comm and widget messages and silent execution, as well as user |
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98 | 98 | code cells.""" |
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99 | 99 | pass |
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100 | 100 | |
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101 | 101 | @_define_event |
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102 | 102 | def pre_run_cell(): |
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103 | 103 | """Fires before user-entered code runs.""" |
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104 | 104 | pass |
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105 | 105 | |
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106 | 106 | @_define_event |
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107 | 107 | def post_execute(): |
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108 | 108 | """Fires after code is executed in response to user/frontend action. |
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109 | 109 | |
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110 | 110 | This includes comm and widget messages and silent execution, as well as user |
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111 | 111 | code cells.""" |
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112 | 112 | pass |
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113 | 113 | |
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114 | 114 | @_define_event |
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115 | 115 | def post_run_cell(): |
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116 | 116 | """Fires after user-entered code runs.""" |
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117 | 117 | pass |
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118 | 118 | |
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119 | 119 | @_define_event |
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120 | 120 | def shell_initialized(ip): |
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121 | 121 | """Fires after initialisation of :class:`~IPython.core.interactiveshell.InteractiveShell`. |
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122 | 122 | |
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123 | 123 | This is before extensions and startup scripts are loaded, so it can only be |
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124 | 124 | set by subclassing. |
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125 | 125 | |
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126 | 126 | Parameters |
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127 | 127 | ---------- |
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128 | 128 | ip : :class:`~IPython.core.interactiveshell.InteractiveShell` |
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129 | 129 | The newly initialised shell. |
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130 | 130 | """ |
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131 | 131 | pass |
@@ -1,32 +1,54 b'' | |||
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1 | 1 | import unittest |
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2 | 2 | try: # Python 3.3 + |
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3 | 3 | from unittest.mock import Mock |
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4 | 4 | except ImportError: |
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5 | 5 | from mock import Mock |
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6 | 6 | |
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7 | 7 | from IPython.core import events |
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8 | 8 | import IPython.testing.tools as tt |
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9 | 9 | |
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10 | 10 | def ping_received(): |
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11 | 11 | pass |
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12 | 12 | |
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13 | 13 | class CallbackTests(unittest.TestCase): |
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14 | 14 | def setUp(self): |
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15 | 15 | self.em = events.EventManager(get_ipython(), {'ping_received': ping_received}) |
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16 | 16 | |
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17 | 17 | def test_register_unregister(self): |
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18 | 18 | cb = Mock() |
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19 | 19 | |
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20 | 20 | self.em.register('ping_received', cb) |
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21 | 21 | self.em.trigger('ping_received') |
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22 | 22 | self.assertEqual(cb.call_count, 1) |
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23 | 23 | |
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24 | 24 | self.em.unregister('ping_received', cb) |
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25 | 25 | self.em.trigger('ping_received') |
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26 | 26 | self.assertEqual(cb.call_count, 1) |
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27 | 27 | |
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28 | 28 | def test_cb_error(self): |
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29 | 29 | cb = Mock(side_effect=ValueError) |
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30 | 30 | self.em.register('ping_received', cb) |
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31 | 31 | with tt.AssertPrints("Error in callback"): |
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32 | 32 | self.em.trigger('ping_received') |
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33 | ||
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34 | def test_unregister_during_callback(self): | |
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35 | invoked = [False] * 3 | |
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36 | ||
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37 | def func1(*_): | |
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38 | invoked[0] = True | |
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39 | self.em.unregister('ping_received', func1) | |
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40 | self.em.register('ping_received', func3) | |
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41 | ||
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42 | def func2(*_): | |
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43 | invoked[1] = True | |
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44 | self.em.unregister('ping_received', func2) | |
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45 | ||
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46 | def func3(*_): | |
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47 | invoked[2] = True | |
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48 | ||
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49 | self.em.register('ping_received', func1) | |
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50 | self.em.register('ping_received', func2) | |
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51 | ||
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52 | self.em.trigger('ping_received') | |
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53 | self.assertEqual([True, True, False], invoked) | |
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54 | self.assertEqual([func3], self.em.callbacks['ping_received']) |
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